This post is inspired by a recent event that lead to temporary closure of Milano Linate, which is Milano second airport, so may be not a major one, but not exactly the municipal airport.
Linate had to be closed, in a planned way, for several hours, for the purpose of chasing hares that were living here. This operation involved many kilometers of nets, and hundred of people to hunt the furry ones. You can find a complete coverage of this event by CBS.
Hare control is really an issue, but most of time the "Faune control units" at the airports deal with birds. The big issue is that large birds can not be easily ingested by engines, and could cause some damages to windshields, wings, and any part of an aircraft.
There is a whole business in chasing birds from airports, with various equipment, including, but not limited to:
-) Remote guns (producing sounds only)
-) Mini fireworks, silent and screaming
-) Loudspeakers prodcasting other birds noises (predator noises)
Part of the problem is also that many airports have open fields where they leave some grass for decoration or ease of maintenance purposes, and this attracts small animals (mice, rats, ...), and when the grass gets its periodical cutting, it does in turn attarcts more birds looking for easy food.
I know a place where they recently tried to leave the grass get longer, but then larger animals started to live here... and to eat the lighting system cables !
To fight against these problems all airports have some "Faune control", patrolling all day long, looking for birds, and trying to chase them.
Wednesday 27 June 2007
Tuesday 26 June 2007
May we have your attention for the following presentation about safety on board
You all have heard at least one these standard safety briefings. They contain however at least two important points that can save your life once.
The first is about not inflating your life jacket before leaving the aircraft. You probably noticed how bloddy long the boarding can be, so imagine what a de-boarding of scared passengenrs can be. Add to that a thick and impractical inflated jacket, and you understand why. The only possible exception to this rule is when the plane is already filled up with water.
To be certified, any airliner must fulfill an evacuation test, consisting in evacuating the total number of passengers via half of the emergency exits within 90 seconds. Sounds crazy ? Recently, an AirFrance Airbus 340 did crash in Toronto, in a survivable way, but caught fire on one side, so they were exactly in the 50% of exits available. And they made it in time. I was quite surprised, because certification always takes place with trained pseudo-passengers, in a relaxed mood.
The other important point in the safety briefing is to put your own oxygen mask first in case of depressurization. This is really a life saver. In case of sudden depressurization at cruise altitude, your lungs won't have enough air pressure to continue transferring oxygen in your blood, hence the masks. The issue is that you have approximately 18 seconds before being so dizzy that you become helpless to anybody or yourself.
Given the noise, sudden drop in temperature and potential fog within the cabin, 18 seconds is not so long to find and put your mask in place. You can then help anyone else, but if you start by helping someone, there are strong chances than you will be incapacited before achieving anything.
One more remark, which is really common sense. Keep your seatbelt fastend after landing until the engines are off and the sign is switched off. First, you won't save any time buckling off early, or may be half a second. But if the pilot has to brake sudenly, you could have a close and unpleasant encounter with the seat in front of you. Beleive me or not, but dozen of people have broken arms, or strong neck injuries yearly because of that... How silly is that ?
To close this post, a sample of safety announcement. The text is the original united one, but the picture...
The first is about not inflating your life jacket before leaving the aircraft. You probably noticed how bloddy long the boarding can be, so imagine what a de-boarding of scared passengenrs can be. Add to that a thick and impractical inflated jacket, and you understand why. The only possible exception to this rule is when the plane is already filled up with water.
To be certified, any airliner must fulfill an evacuation test, consisting in evacuating the total number of passengers via half of the emergency exits within 90 seconds. Sounds crazy ? Recently, an AirFrance Airbus 340 did crash in Toronto, in a survivable way, but caught fire on one side, so they were exactly in the 50% of exits available. And they made it in time. I was quite surprised, because certification always takes place with trained pseudo-passengers, in a relaxed mood.
The other important point in the safety briefing is to put your own oxygen mask first in case of depressurization. This is really a life saver. In case of sudden depressurization at cruise altitude, your lungs won't have enough air pressure to continue transferring oxygen in your blood, hence the masks. The issue is that you have approximately 18 seconds before being so dizzy that you become helpless to anybody or yourself.
Given the noise, sudden drop in temperature and potential fog within the cabin, 18 seconds is not so long to find and put your mask in place. You can then help anyone else, but if you start by helping someone, there are strong chances than you will be incapacited before achieving anything.
One more remark, which is really common sense. Keep your seatbelt fastend after landing until the engines are off and the sign is switched off. First, you won't save any time buckling off early, or may be half a second. But if the pilot has to brake sudenly, you could have a close and unpleasant encounter with the seat in front of you. Beleive me or not, but dozen of people have broken arms, or strong neck injuries yearly because of that... How silly is that ?
To close this post, a sample of safety announcement. The text is the original united one, but the picture...
Monday 25 June 2007
Captain on the bridge - Handcuffs and tigers
Ok, this old naval idiom is no longer used when a flight captain enters or leaves a cockpit, but some captain prerogatives survived the time when they change from boats to planes.
Let me first be a bit disapointing for all romantic readers... a flight captain can not get passenger married. This stopped when the move from ship to boat took place... sorry.
Amongst his trendemous responsibilities, the captain is sole responsible for the safety of all passengers and crew on board. This means that he can take any action he think is needed to protect aircraft and passenger safety, even if this violates each and every other rules ! Be sure he would have to report to ATC, aviation authorities, and his airline, but this will be later on. In the action, the captain is really the one deciding things.
Now, something else we heard a lot in the media recently as a french TV producer created an incident on board a flight from South Africa to Paris. The captain of a flight can decide to put a passenger under arrest, and if deemed necessary, to have the crew restraining the passenger freedom of movement, by using handcuffs.
A final word to close this post, about policemen flying on airliners. In the industry wording, they are called "tigers". Even the crew does not know them, and they interveine only if the safety of the flight is endangered by unlawful interference. They won't move if something only looks suspicious, or if a passenger is misbehaving under influence of alcohol or so.
This restriction in their actions is to protect their identity. There are not so many of them, and if they had to act for any small incident, it would be easy for terrorists to identify them, even by creating incidents with the sole purpose of then neutralize the tigers.
Be sure that many airliner seats daily are occupied by tigers, and this helps passenger safety.
Let me first be a bit disapointing for all romantic readers... a flight captain can not get passenger married. This stopped when the move from ship to boat took place... sorry.
Amongst his trendemous responsibilities, the captain is sole responsible for the safety of all passengers and crew on board. This means that he can take any action he think is needed to protect aircraft and passenger safety, even if this violates each and every other rules ! Be sure he would have to report to ATC, aviation authorities, and his airline, but this will be later on. In the action, the captain is really the one deciding things.
Now, something else we heard a lot in the media recently as a french TV producer created an incident on board a flight from South Africa to Paris. The captain of a flight can decide to put a passenger under arrest, and if deemed necessary, to have the crew restraining the passenger freedom of movement, by using handcuffs.
A final word to close this post, about policemen flying on airliners. In the industry wording, they are called "tigers". Even the crew does not know them, and they interveine only if the safety of the flight is endangered by unlawful interference. They won't move if something only looks suspicious, or if a passenger is misbehaving under influence of alcohol or so.
This restriction in their actions is to protect their identity. There are not so many of them, and if they had to act for any small incident, it would be easy for terrorists to identify them, even by creating incidents with the sole purpose of then neutralize the tigers.
Be sure that many airliner seats daily are occupied by tigers, and this helps passenger safety.
Sunday 24 June 2007
Planes and cell-phones
You certainly all know that it is forbidden to use cell phones on board planes. Let's talk about that, as this is something some people find frustrating, let's have a look at that. This is a particularly hot topic as some airlines (including Air France) are now allowing this, via their own antenna on board.
As a cell-phone owner, you probably already noticed that when you put it beside a radio or a tv, when someone's calling you, the tv / radio speakers are disturbed and emitt loud cracks. But as soon as you get your cell-phone away, the cracks diminish quickly.
These cracks come from the interference between your sound system and the microwave-like waves used by the cell phone technology. In a plane, the same could occur. And as the plane antenna are dispatched under the fuselage at various places, a cell-phone could potentially generate the same cracks in the radio used by pilots to communicate with air-traffic control, or for with the radio-navigation system.
From a technical point of view, the probability is extremely remote, but hey, would you like to take a chance ? Imagine for a second that your phone creates an interference with the instrument landing receiver while the plane is following its signal, 30 meters above groud, and give then an incorrect indication to the autopilot. This phone call could have been delayed... no ?
So the easiest is to switch off your phone while boarding the plane. You will then avoid dancing while seated to find it in your pockets, and have a longer "phone off relaxation" time.
As a cell-phone owner, you probably already noticed that when you put it beside a radio or a tv, when someone's calling you, the tv / radio speakers are disturbed and emitt loud cracks. But as soon as you get your cell-phone away, the cracks diminish quickly.
These cracks come from the interference between your sound system and the microwave-like waves used by the cell phone technology. In a plane, the same could occur. And as the plane antenna are dispatched under the fuselage at various places, a cell-phone could potentially generate the same cracks in the radio used by pilots to communicate with air-traffic control, or for with the radio-navigation system.
From a technical point of view, the probability is extremely remote, but hey, would you like to take a chance ? Imagine for a second that your phone creates an interference with the instrument landing receiver while the plane is following its signal, 30 meters above groud, and give then an incorrect indication to the autopilot. This phone call could have been delayed... no ?
So the easiest is to switch off your phone while boarding the plane. You will then avoid dancing while seated to find it in your pockets, and have a longer "phone off relaxation" time.
Saturday 23 June 2007
What planes can and can't do - Wind
One important thing when talking about aerodynamics is that the speed which is relevant in lift generation is the relative speed between air and wing. Speed relatively to ground has no influence, except for take-off and landing.
If wind is blowing, planes will take-off and land in opposite direction, so for the same air speed (needed to generate lift) the ground speed will be less, so the ground roll will be shorter, and more controllable.
The problem with wind start when they are fluctuating. If there is a sudden change in wind speed during an approach (what is called a "windshear"), the relative airspeed could be significantly changed, leading to potentailly strong changes in lift, then in vertical speed.
By chance, modern airliners have computers that know the airspeed from airspeed sensors, and groundspeed from GPS, so they can detect any windshear and notify them to pilots. The only "cure" is just to apply full power, and go arround for a second approach.
The other major issue with wind is when it is not blowing parallel to the runway. As the plane is moving relatively to air, the only way to maintain a straight ground track (needed for landing, isn'it ?) is to fly with the nose in the wind direction, flying in a "crabby" fashion.
This is perfectly ok to maintain a trajectory relatively to ground, but raises an issue, as the landing gear are not orientable, so immediately before (in some case after...) landing, the plane must be put in line with the runway.
Some examples of this technique are shows in the following video. Please understand that clearly, what you will see is indeed very good pilot skills, not bloody pilots missing their landings.
The next video is from a simulator (no airline will ever allow its pilots to even try such an approach), but it is very good for demonstration, as it shows the same approach from outsite and inside the planes, with angles that would be impossible to shoot from in reality.
The next time you will have a firm landing in crosswind conditions, or a go arround, please remind that this is how to do. And a go arround is never a bad option.
If wind is blowing, planes will take-off and land in opposite direction, so for the same air speed (needed to generate lift) the ground speed will be less, so the ground roll will be shorter, and more controllable.
The problem with wind start when they are fluctuating. If there is a sudden change in wind speed during an approach (what is called a "windshear"), the relative airspeed could be significantly changed, leading to potentailly strong changes in lift, then in vertical speed.
By chance, modern airliners have computers that know the airspeed from airspeed sensors, and groundspeed from GPS, so they can detect any windshear and notify them to pilots. The only "cure" is just to apply full power, and go arround for a second approach.
The other major issue with wind is when it is not blowing parallel to the runway. As the plane is moving relatively to air, the only way to maintain a straight ground track (needed for landing, isn'it ?) is to fly with the nose in the wind direction, flying in a "crabby" fashion.
This is perfectly ok to maintain a trajectory relatively to ground, but raises an issue, as the landing gear are not orientable, so immediately before (in some case after...) landing, the plane must be put in line with the runway.
Some examples of this technique are shows in the following video. Please understand that clearly, what you will see is indeed very good pilot skills, not bloody pilots missing their landings.
The next video is from a simulator (no airline will ever allow its pilots to even try such an approach), but it is very good for demonstration, as it shows the same approach from outsite and inside the planes, with angles that would be impossible to shoot from in reality.
The next time you will have a firm landing in crosswind conditions, or a go arround, please remind that this is how to do. And a go arround is never a bad option.
Friday 22 June 2007
Is that a runway ? Is it the good one ?
These questions look silly to you, don't they ?
You would then be surprised by the number of pilots who approached and / or landing to a wrong runway, a taxiway, a runway at an other airport, or a nearby bridge or motorway.
This could look silly, but it's not always so obvious to identify a runway when taxing at night, especially when it's raining and light is creating tons of reflections...
One business jet pilot once told me about a taxi clearance he got from Brussells ground controller after vacating the runway... it involved about 10 different taxiways !!
One of the latest avionics development concerns runway incursion warning system, based on GPS signals which are accurate enough to know if the place is on a runway or a taxiway.
There is a urban legend about this in Frankfurt, where the controllers are known to be expecting pilots to taxi from runway to their gate on their own, which is quite hard on such a complex airport. The story tells that a british pilot, who converted to airline pilot after world war II did land there... the following dialog then took place:
Controller: Speedbird 1234, taxi to gate 45 via standard taxi route
Speedbird 1234: Sorry Sir, we're not familliar with the airport, request detailled taxi clearance.
Controller (a bit pissy): Speedbird 1234, did you never come to Frankfurt before ?
Speedbird 1234 (with british flegm): Yes Sir, I did, but did not stop and dropped things over
The legend don't says anything about the controller's answer.
You may be noticed big number painted on runways, to identify them. These come from runway angle with respect to magnetic north, rounded by 10 degrees. So a runway 23 has a magnetical orientation between 225 and 235 degrees. This is also why the numbers at each end are different, and always different by 18 !
So, what about parallel runways ? Dialog between pilot and controller must be unambiguous. When an airport has several parallel runways, they are then designated by their number, followed by L (left) or R (right). So if an airport has two runway with an orientation of 70° with respect to magnetic north, they will be 07L and 07R, and in the other direction 25R and 07L respectively.
Final trick, if an airport has 3 parallel runways, the center one will be designated 07C (center).
One note before I stop this already too long post (I told you I'm passionated about that). To be able to operate runways completely independently, that is to be sure there is no influence of traffic on one regarding traffic to the other, their centerlines must be 700 meters apart.
PS: if you see in a movie with Leo Di Caprio and Tom Hanks (Catch me if you can) a plane being cleared to land on runway 59, you'll know that it's not correct !
You would then be surprised by the number of pilots who approached and / or landing to a wrong runway, a taxiway, a runway at an other airport, or a nearby bridge or motorway.
This could look silly, but it's not always so obvious to identify a runway when taxing at night, especially when it's raining and light is creating tons of reflections...
One business jet pilot once told me about a taxi clearance he got from Brussells ground controller after vacating the runway... it involved about 10 different taxiways !!
One of the latest avionics development concerns runway incursion warning system, based on GPS signals which are accurate enough to know if the place is on a runway or a taxiway.
There is a urban legend about this in Frankfurt, where the controllers are known to be expecting pilots to taxi from runway to their gate on their own, which is quite hard on such a complex airport. The story tells that a british pilot, who converted to airline pilot after world war II did land there... the following dialog then took place:
Controller: Speedbird 1234, taxi to gate 45 via standard taxi route
Speedbird 1234: Sorry Sir, we're not familliar with the airport, request detailled taxi clearance.
Controller (a bit pissy): Speedbird 1234, did you never come to Frankfurt before ?
Speedbird 1234 (with british flegm): Yes Sir, I did, but did not stop and dropped things over
The legend don't says anything about the controller's answer.
You may be noticed big number painted on runways, to identify them. These come from runway angle with respect to magnetic north, rounded by 10 degrees. So a runway 23 has a magnetical orientation between 225 and 235 degrees. This is also why the numbers at each end are different, and always different by 18 !
So, what about parallel runways ? Dialog between pilot and controller must be unambiguous. When an airport has several parallel runways, they are then designated by their number, followed by L (left) or R (right). So if an airport has two runway with an orientation of 70° with respect to magnetic north, they will be 07L and 07R, and in the other direction 25R and 07L respectively.
Final trick, if an airport has 3 parallel runways, the center one will be designated 07C (center).
One note before I stop this already too long post (I told you I'm passionated about that). To be able to operate runways completely independently, that is to be sure there is no influence of traffic on one regarding traffic to the other, their centerlines must be 700 meters apart.
PS: if you see in a movie with Leo Di Caprio and Tom Hanks (Catch me if you can) a plane being cleared to land on runway 59, you'll know that it's not correct !
Wednesday 20 June 2007
Airport population - The spotters
The spotters are definetly part of airport population, despite they are not working there (not earning money at least), and they are usually not allowed to get in.
They express their passion for aviation by taking pictures of planes, mostly from the airport fence. On good days, you can have dozen, if not hundreds of them, especially if there are some special planes scheduled.
Some of them are equipped with radio scanners to monitor the traffic, and even some radar-like (ADS-B) receivers to prepare their shots.
This could look like a strange hobby, but I must admit that they are really serious at it. Have a look at www.airliners.net, you will see how good their pictures are.
And please don't think this is useless, it even had strategical issues... do you remind when CIA was accused to illegaly transport war prisonners accross europe ? Some spotters could prove using their pictures that the agency did illegaly used the same plane with different registrations within days. How ? Because the spotters photos are so good that they could unambiguously identify the planes by their antenna locations, and also because of the scratches on the fuselage !
There is also a second kind of spotting activity, which is a bit harder for me to understand, which consists in noting the aircraft registrations seen by the spotter. At some airports with public observation desks, you can see them, with binoculars, looking at planes, then flipping pages of their booklets to tick the registration they just saw... and get very excited if this is a new one.
Some spotters club even require a certain ammount of new registration seen per member, otherwise the "bad" member no seeing enough new planes gets excluded !
During some renovations at Heathrow, the fence was coverd by kind of opaque plastic film, and the authority has been asked and pressured by spotters associations to do some holes in that, so they could continue their favorite activity ! That's how powerfull this funny lobby is.
The guy on this picture is a typical spotter being spotted in action... He is in fact Kurt Gorm Larsen, the editor of www.plane-spotter.com, another spotters website. And yes, that equipment is quite usual amongts spotters as they have to shoot their pictures from quite fare away, behind the fence.
They express their passion for aviation by taking pictures of planes, mostly from the airport fence. On good days, you can have dozen, if not hundreds of them, especially if there are some special planes scheduled.
Some of them are equipped with radio scanners to monitor the traffic, and even some radar-like (ADS-B) receivers to prepare their shots.
This could look like a strange hobby, but I must admit that they are really serious at it. Have a look at www.airliners.net, you will see how good their pictures are.
And please don't think this is useless, it even had strategical issues... do you remind when CIA was accused to illegaly transport war prisonners accross europe ? Some spotters could prove using their pictures that the agency did illegaly used the same plane with different registrations within days. How ? Because the spotters photos are so good that they could unambiguously identify the planes by their antenna locations, and also because of the scratches on the fuselage !
There is also a second kind of spotting activity, which is a bit harder for me to understand, which consists in noting the aircraft registrations seen by the spotter. At some airports with public observation desks, you can see them, with binoculars, looking at planes, then flipping pages of their booklets to tick the registration they just saw... and get very excited if this is a new one.
Some spotters club even require a certain ammount of new registration seen per member, otherwise the "bad" member no seeing enough new planes gets excluded !
During some renovations at Heathrow, the fence was coverd by kind of opaque plastic film, and the authority has been asked and pressured by spotters associations to do some holes in that, so they could continue their favorite activity ! That's how powerfull this funny lobby is.
The guy on this picture is a typical spotter being spotted in action... He is in fact Kurt Gorm Larsen, the editor of www.plane-spotter.com, another spotters website. And yes, that equipment is quite usual amongts spotters as they have to shoot their pictures from quite fare away, behind the fence.
What planes can and can't do - Fog
The final approach of each flight is guided using a so called "Instrument Landing System", allowing planes to be guided laterrally when lined up with runway, and vertically as well, in an automated manner.
There are three categories of ILS approaches, namely I, II, and III :-). The difference between them is what we call the "minimums", which are conditions defining at what point of the approach the crew must have runway in sight, or go arround and take another chance or divert.
I won't explain the working or ILS here, but just give some ideas of the minimums and what is required to go there, and how it looks like.
Most airlines operate with ILS up to category II, which is a minimal ceiling of 100 ft above ground level (30 meters), and an horizontal visibility of 350 meters. I don't know if you realise what that means for a pilot to gain sight of where he will have to land only from 30 meters, and to land at a speed of 150 kts (about 300 km / h) in a visibility of 350 meters !
Category III is even more impressive, as it can be up to ... zero visibility. In this case, the landing is fully automatic, with two autopilots and a third computer managing the power automatically, plus a radio altimeter measuring accurately the vertical distance.
There are a lot of conditions associated to Cat II / III operations, including:
- Crew certification
- Plane certification
- ILS being powered with backup local generators to ensure no interruptions
- No one within the ILS shelter
- No visitor in the cockpit
- No plane / vehicle in close vicinity of the runway to ensure top quality ILS signals
God bless the ILS and autopilots.
But then you will ask... how can fog create so huge delays then ?
This is mostly because all airliners are not operating Cat III, and sometimes fog creates conditions that does not allow for Cat II landings... but the main reason is ground operations then.
To give you an idea of what fog is, what is seen on this picture is not problematic at all. A plane at the category II minimas would gain sight of runway approximately 30 meters above ground, where the approach lights seen on this picture are red !
It is really hard for pilots and ground controllers to manage proper taxi operations within fog. Final approach and landing along the ILS is easy, but there is no guidance other than visual for taxiing, so how would you taxi if you can't see more that 200 meters or even less what's come in front of your 400 tons plane ?
I remind being the tour guide for visitors once in a control tower on a foggy day... they were quite disapointed as the runway was not visible from tower because the fog was so dense. But they could testify that the ground radar was working properly.
There are three categories of ILS approaches, namely I, II, and III :-). The difference between them is what we call the "minimums", which are conditions defining at what point of the approach the crew must have runway in sight, or go arround and take another chance or divert.
I won't explain the working or ILS here, but just give some ideas of the minimums and what is required to go there, and how it looks like.
Most airlines operate with ILS up to category II, which is a minimal ceiling of 100 ft above ground level (30 meters), and an horizontal visibility of 350 meters. I don't know if you realise what that means for a pilot to gain sight of where he will have to land only from 30 meters, and to land at a speed of 150 kts (about 300 km / h) in a visibility of 350 meters !
Category III is even more impressive, as it can be up to ... zero visibility. In this case, the landing is fully automatic, with two autopilots and a third computer managing the power automatically, plus a radio altimeter measuring accurately the vertical distance.
There are a lot of conditions associated to Cat II / III operations, including:
- Crew certification
- Plane certification
- ILS being powered with backup local generators to ensure no interruptions
- No one within the ILS shelter
- No visitor in the cockpit
- No plane / vehicle in close vicinity of the runway to ensure top quality ILS signals
God bless the ILS and autopilots.
But then you will ask... how can fog create so huge delays then ?
This is mostly because all airliners are not operating Cat III, and sometimes fog creates conditions that does not allow for Cat II landings... but the main reason is ground operations then.
To give you an idea of what fog is, what is seen on this picture is not problematic at all. A plane at the category II minimas would gain sight of runway approximately 30 meters above ground, where the approach lights seen on this picture are red !
It is really hard for pilots and ground controllers to manage proper taxi operations within fog. Final approach and landing along the ILS is easy, but there is no guidance other than visual for taxiing, so how would you taxi if you can't see more that 200 meters or even less what's come in front of your 400 tons plane ?
I remind being the tour guide for visitors once in a control tower on a foggy day... they were quite disapointed as the runway was not visible from tower because the fog was so dense. But they could testify that the ground radar was working properly.
Airport's best spot - Lighting system
Before writing this post, I had a long time thinking what my favorite place on an airport it. This is not a easy thing to determine as there are so many different interesting and funny places to be !Driving beside or even on runways (with a clearance, for sure) is good...
Walking arround planes at their stands offers the possiblity to see each and every details of them...
The view from control tower is definetily breathtaking...
But THE place to be is withing the approach light system. You know, this series of lights that extend for 900 meters from runway end, guiding pilots for the very final part of the approach.
Getting there is not an easy thing as this is in the sensitive area, and only people doing maintenance of the lights are allowed to go there, as well as the Instrument Landing System (ILS) technicians. But the place is really good, as it is the closes place in the runway axis you can access.
If you're facing take-offs, depending the runway lenght and type of aircraft taking off, you can have kind of a "face to face" with the pilots, and beleive me, they will see you as well.
But landings seen from there is really a paramount experience, as airplanes pass above you, at a height of about 10 to 15 meters with reduced power, gliding down to the runway, with light on, gear down... really exciting. After the plane passes, you can even hear the wake turbulence moving air arround, and feel those vortexes...
Far far away in time is the era where it was possible to buy a sandwich at noon and go there to eat it looking at planes (the new safety era...) but each opportunity to go there is a good time granted.
Both photos in this post are from the excellent www.airliners.net website, which photo database is fed by spotters worldwide, and has more that 1'000'000 photos in.
More about the spotters in the next post...
Saturday 16 June 2007
What planes can and can't do - Thunderstorms and hail
This post is the first in a series explaining what is possible, and what's not possible for modern airliners. One of the major dangers come from thunderstorms, a.k.a Cumulonimbus, or CB's.
The good thing with thunderstorms is that they are easy to spot, be it visually by day, or by aircraft weather radar when in clouds, or at night.
The very bad thing about the is that they represent an extreme danger to planes, and can not be flown through. Never. The dangers found in them are turbulences, with updrafts and downdrafts strong enough to literally break any plane in pieces. You must imagine that a typical CB is 10 kilometers wide, can be up to 12 km high, and contains an enormous ammount of energy. Winds in in can have vertical speeds of dozen of meters per seconds, and change radically over meters only.
Another danger present in CBs are hailstones. Ok, you just think now of the size of hailstones you know from your ground experience. But the one you can "meet" on ground are already parlty melt because of their descent time. The hailstones within a CB can be as big as grapefruits or ananas... and fly horizontally in strong winds.
Recently, and easyjet boeing 737 has been hit by a hailstorm, without actually flying in a CB. The crew declared emergency and came back for immediate landing. Strangely, neither airborne weather radar nor ground based weather radar did detect that sudden storm.
The following pictures will give you an idea how the plane was damaged. Nevertheless, the crew could fly it back normally, but obviously the co-pilot (sitting right) had to land.
And once again, this plane did not flew through a thunderstorm, it has "only" be hit by a hailstorm.
I have no pictures of planes that flew through a thunderstorm, because they dont. The normal distance that most of the companies require from their pilots is 10 nautical miles from the CB border, this is about 18 kilometers.
My personnal closest encounter with a CB was as a PAX, at night. There was a CB line on our flight path, it was a late flight, and the only alternate would have been one flying hour away. The captain did spot a hole on the weather radar... He used the public address to say "Cabin crew, take your seats... quickly". We had then two minutes of very severe turbulence. It was so severe that if someone had not been with seatbelt fastened, he would probably have been severly injured by hitting the ceiling. The atmosphere in the plane after that was suddenly very silent. After landing, I had a short chat with the captain, and asked him about the distance. His answer (which I beleive is true) is that we were 5 nautical miles (9 kilometers) from the CB's border.
Something additional, a friend operating in a local company told me that he once had a lighting strike while flying 10 miles (18 kilometers) away from the CB. This is usually not a problem, as planes are perfect Faraday cages. The only risk is damage to the radios, but a plane can not explode becose of a lightning strike.
An additional danger that is present in thunderstorms is icing, but I will say more on that on a later post.
One last thing about moderate to severe turbulence. In mid to large size airliners, the wings are flexible by design. Thus it is perfectly normal and safe to see the wings moving up and down in turbulence. There is an enormous safety margin in design, and I know no case of planes the have been "destroyed in the air" by turbulence... except the very few that flew through CBs.
The good thing with thunderstorms is that they are easy to spot, be it visually by day, or by aircraft weather radar when in clouds, or at night.
The very bad thing about the is that they represent an extreme danger to planes, and can not be flown through. Never. The dangers found in them are turbulences, with updrafts and downdrafts strong enough to literally break any plane in pieces. You must imagine that a typical CB is 10 kilometers wide, can be up to 12 km high, and contains an enormous ammount of energy. Winds in in can have vertical speeds of dozen of meters per seconds, and change radically over meters only.
Another danger present in CBs are hailstones. Ok, you just think now of the size of hailstones you know from your ground experience. But the one you can "meet" on ground are already parlty melt because of their descent time. The hailstones within a CB can be as big as grapefruits or ananas... and fly horizontally in strong winds.
Recently, and easyjet boeing 737 has been hit by a hailstorm, without actually flying in a CB. The crew declared emergency and came back for immediate landing. Strangely, neither airborne weather radar nor ground based weather radar did detect that sudden storm.
The following pictures will give you an idea how the plane was damaged. Nevertheless, the crew could fly it back normally, but obviously the co-pilot (sitting right) had to land.
And once again, this plane did not flew through a thunderstorm, it has "only" be hit by a hailstorm.
I have no pictures of planes that flew through a thunderstorm, because they dont. The normal distance that most of the companies require from their pilots is 10 nautical miles from the CB border, this is about 18 kilometers.
My personnal closest encounter with a CB was as a PAX, at night. There was a CB line on our flight path, it was a late flight, and the only alternate would have been one flying hour away. The captain did spot a hole on the weather radar... He used the public address to say "Cabin crew, take your seats... quickly". We had then two minutes of very severe turbulence. It was so severe that if someone had not been with seatbelt fastened, he would probably have been severly injured by hitting the ceiling. The atmosphere in the plane after that was suddenly very silent. After landing, I had a short chat with the captain, and asked him about the distance. His answer (which I beleive is true) is that we were 5 nautical miles (9 kilometers) from the CB's border.
Something additional, a friend operating in a local company told me that he once had a lighting strike while flying 10 miles (18 kilometers) away from the CB. This is usually not a problem, as planes are perfect Faraday cages. The only risk is damage to the radios, but a plane can not explode becose of a lightning strike.
An additional danger that is present in thunderstorms is icing, but I will say more on that on a later post.
One last thing about moderate to severe turbulence. In mid to large size airliners, the wings are flexible by design. Thus it is perfectly normal and safe to see the wings moving up and down in turbulence. There is an enormous safety margin in design, and I know no case of planes the have been "destroyed in the air" by turbulence... except the very few that flew through CBs.
Friday 15 June 2007
Tarmac driving school
One of the most funny, but potentially stressful thing to do on an airport, as an insider, is to drive on the tarmac. There are a few additional rules compared to public roads driving, and it's not such an easy environment.
The first rule is easy. If you've got a plane vs. car incident, the car driver is guilty. Always. Even if the plane pilot is blind, drunk, and sleepy (be relaxed, they're not). The good part is that airliners are so HUGE that you can harldy not see them... except if you're blind, drunk and sleepy ;-)
But light jets, and more generally speaking light aircrafts are much smaller, and can taxi quite fast, so you have to be careful.
Something else that make this exercise not so easy is that there are no roads on airports, at least not on main tarmac. No roads borders, no streets, all what you get is a mixed set of lines on the ground. Even crossings, stops, give-way signs are painted instead of being on signs, to avoid them being obstacles to taxiing planes. Needless to say, only a few traffic lights, not applicable to planes.
Apart from the shame of hitting a plane with your car, the other big risk is jet-blast. To be safe, one must cross behind a plane at a distance equivalent to at least three times the plane length. Except on spots dedicated to engine tests, which can have terrible effects. To be convinced of that, here is a classical training video from United.
This is usually shown during theory training sessions. Yes, there are dedicated driving schools run by the airport authorities, and some require theoretical and practical testing.
These lessons also includes rules on where cars are allowed, where they can park, and special areas with restricted access. These areas, mainly runways and taxiways, can be accessed only with a clearance from the ground controller, according to ground traffic.
One final remark, about firemen flashlights. When looking at an airport, you can nearly always see firemen trucks arround one airplane or another. 95% of the time, they are doing on job training. The easy way to distinguish a true emergency from a routine exercise is to look at the flashlights. Orange means training, or normal movement, whereas blue flashlights are reserved for actual emergencies in progress.
So next time you see a firetruck beside your plane, with orange lights on it, stay cool, but if the blue lights are on......
The first rule is easy. If you've got a plane vs. car incident, the car driver is guilty. Always. Even if the plane pilot is blind, drunk, and sleepy (be relaxed, they're not). The good part is that airliners are so HUGE that you can harldy not see them... except if you're blind, drunk and sleepy ;-)
But light jets, and more generally speaking light aircrafts are much smaller, and can taxi quite fast, so you have to be careful.
Something else that make this exercise not so easy is that there are no roads on airports, at least not on main tarmac. No roads borders, no streets, all what you get is a mixed set of lines on the ground. Even crossings, stops, give-way signs are painted instead of being on signs, to avoid them being obstacles to taxiing planes. Needless to say, only a few traffic lights, not applicable to planes.
Apart from the shame of hitting a plane with your car, the other big risk is jet-blast. To be safe, one must cross behind a plane at a distance equivalent to at least three times the plane length. Except on spots dedicated to engine tests, which can have terrible effects. To be convinced of that, here is a classical training video from United.
This is usually shown during theory training sessions. Yes, there are dedicated driving schools run by the airport authorities, and some require theoretical and practical testing.
These lessons also includes rules on where cars are allowed, where they can park, and special areas with restricted access. These areas, mainly runways and taxiways, can be accessed only with a clearance from the ground controller, according to ground traffic.
One final remark, about firemen flashlights. When looking at an airport, you can nearly always see firemen trucks arround one airplane or another. 95% of the time, they are doing on job training. The easy way to distinguish a true emergency from a routine exercise is to look at the flashlights. Orange means training, or normal movement, whereas blue flashlights are reserved for actual emergencies in progress.
So next time you see a firetruck beside your plane, with orange lights on it, stay cool, but if the blue lights are on......
Airport - Airline and Air traffic control
These are three major actors of airport life, and air transport industry.
From the point of view of a PAX (remember, the "code name" for passenger), the role of the airline is quite easy. Operate the plane safely.
ATC is a bit more mysterious, but anyone already heard about the guys in "tower" giving clerarances to planes. There is much more to tell about ATC, but for the time being, this is enough. Just keep in mind that ATC is responsible to keep planes separated from each other, and in european context to have them respecting their departure time "slots".
The third A - Airport authority - is even more transparent to a PAX, but it plays a major role. These guys are in charge of runing the airport itself, which from operational point of view means airplane parking management, providing power and air-conditionning to planes while they're on ground, and so on.
Short break here for a funny thing to look at during your next trip. Each time a plane taxies (drives in) into its stand (parking place) one off the ground staff plugs an electrical cable below the plane nose. This is not to charge the plane batteries, but to provide it with ground produced power. This frequently occurs even before the engines are stopped... because most of ground services fees are based on how much time power was supplied to the plane, as it is easy to measure. Next time you're waiting, look at the powerplug guys.
Now, look at the various interests of our three actors.
Airlines want short ground times, as they earn money by flying and respecting their schedules.
Airports want to sell services to planes, based on the time they stay... but on the other hand, they are payed per passenger and per landing, so they want to be expeditious, but not too much.
ATC want to keep planes on schedules, and avoid traffic congestion. And under some circumstances, delays are imposed to planes, to avoid congestion at destination or enroute.
Now they all have secondary wishes. Typically, airlines want convenient schedules for their PAX, and possibly easy to memorise. Who would like to leave europe to the states in the evening, and be there at night ? Also take a look once at the departure panels, and try to count the number of flights leaving, let's say, at 08h00. Having 5 or 6 of such flights at airports with a single runway is by far not uncommon, but as ATC has to separate departures by at least one minute (sometimes more), how the hell could it be possible to have 6 departures within the same minute ?
The funny thing is that ATC can not refuse a flight plan, airport authorities can impose airport slots to companies, but no one is co-ordinating all of that by the minute, and in fact this is quite good, because PAX themselves are frequently out of control. How could you expect 200 travellers to reach the plane, all on time, with no boarding problems, no one being "delayed" by shopping, or just being late ?
So airlines, airports and air traffic control all know that all the 08h00 planes won't leave all at the same time, and that's what makes the traffic situation different each and every day. Nothing in common with trains !
One more thing, about slots. When a flight is imposed a slot, it means that the flow control unit managing all of european sky from Brussels computed its departure time to avoid any congestion en route or at destination, but as we've just seen, the departure time can not be by the minute, so a slot is valid for 20 minutes, 5 before the computed take-off time (CTOT) and 15 minutes after. If your captain can not manage that... you need a new slot, which can be 2h later.
This can look bad, but I'm sure that as a PAX, and particularly if you're ecologist, you prefer to wait on ground than in the air, don't you ?
So next time your captain says that you missed your slot, ask yourself if there were delayed passengers, or if you're flying to a busy airport... and if you get off the plane because the new slot is too late, be sure that:
1) Airline is getting mad about not earning money in flight
2) ATC is happy you're not causing congestion and remain safe
3) Airport Authority is really happy to sell more power to your airline, and to welcome you in the shops and bars
A tip to close this post: if you're delayed and not yet on board the plane, don't forget to ask ground staff (airline or handling agent) to give you a drink / sandwich voucher. They will never refuse, but will never offer that spontaneously.
Have a safe flight ;-)
From the point of view of a PAX (remember, the "code name" for passenger), the role of the airline is quite easy. Operate the plane safely.
ATC is a bit more mysterious, but anyone already heard about the guys in "tower" giving clerarances to planes. There is much more to tell about ATC, but for the time being, this is enough. Just keep in mind that ATC is responsible to keep planes separated from each other, and in european context to have them respecting their departure time "slots".
The third A - Airport authority - is even more transparent to a PAX, but it plays a major role. These guys are in charge of runing the airport itself, which from operational point of view means airplane parking management, providing power and air-conditionning to planes while they're on ground, and so on.
Short break here for a funny thing to look at during your next trip. Each time a plane taxies (drives in) into its stand (parking place) one off the ground staff plugs an electrical cable below the plane nose. This is not to charge the plane batteries, but to provide it with ground produced power. This frequently occurs even before the engines are stopped... because most of ground services fees are based on how much time power was supplied to the plane, as it is easy to measure. Next time you're waiting, look at the powerplug guys.
Now, look at the various interests of our three actors.
Airlines want short ground times, as they earn money by flying and respecting their schedules.
Airports want to sell services to planes, based on the time they stay... but on the other hand, they are payed per passenger and per landing, so they want to be expeditious, but not too much.
ATC want to keep planes on schedules, and avoid traffic congestion. And under some circumstances, delays are imposed to planes, to avoid congestion at destination or enroute.
Now they all have secondary wishes. Typically, airlines want convenient schedules for their PAX, and possibly easy to memorise. Who would like to leave europe to the states in the evening, and be there at night ? Also take a look once at the departure panels, and try to count the number of flights leaving, let's say, at 08h00. Having 5 or 6 of such flights at airports with a single runway is by far not uncommon, but as ATC has to separate departures by at least one minute (sometimes more), how the hell could it be possible to have 6 departures within the same minute ?
The funny thing is that ATC can not refuse a flight plan, airport authorities can impose airport slots to companies, but no one is co-ordinating all of that by the minute, and in fact this is quite good, because PAX themselves are frequently out of control. How could you expect 200 travellers to reach the plane, all on time, with no boarding problems, no one being "delayed" by shopping, or just being late ?
So airlines, airports and air traffic control all know that all the 08h00 planes won't leave all at the same time, and that's what makes the traffic situation different each and every day. Nothing in common with trains !
One more thing, about slots. When a flight is imposed a slot, it means that the flow control unit managing all of european sky from Brussels computed its departure time to avoid any congestion en route or at destination, but as we've just seen, the departure time can not be by the minute, so a slot is valid for 20 minutes, 5 before the computed take-off time (CTOT) and 15 minutes after. If your captain can not manage that... you need a new slot, which can be 2h later.
This can look bad, but I'm sure that as a PAX, and particularly if you're ecologist, you prefer to wait on ground than in the air, don't you ?
So next time your captain says that you missed your slot, ask yourself if there were delayed passengers, or if you're flying to a busy airport... and if you get off the plane because the new slot is too late, be sure that:
1) Airline is getting mad about not earning money in flight
2) ATC is happy you're not causing congestion and remain safe
3) Airport Authority is really happy to sell more power to your airline, and to welcome you in the shops and bars
A tip to close this post: if you're delayed and not yet on board the plane, don't forget to ask ground staff (airline or handling agent) to give you a drink / sandwich voucher. They will never refuse, but will never offer that spontaneously.
Have a safe flight ;-)
Thursday 14 June 2007
Set the context...
An airport can hardly be compared to any other activity center... there are thousands of people working there, for hundreds of companies, each with different aims, some can be state operated, other are purely private companies... but by the end of the day, all want to keep the passengers (we call them PAX) happy, and the traffic smooth.
There are certainly bigger companies employing more people, but remind that an airport is not made of a single company, but many of them, typically including:
-Airport authority
-Air traffic control
-Airlines
-Police
-Firemen
-PAX security
-Handling (check-in and boarding)
-Fuel companies
-Catering
-Planes cleaning
-Aicraft maintenance
-Medical services
- ... and I probably forgot many.
and for most of these activities, airports have various companies offering services. Moreover, most airports are now shopping centers as well. A typical mid-size european airport (taking away Heathrow, Frankfurt, Charles-De-Gaule and Madrid) has something like 10'000 to 25'000 on site workers. Hopefully not all at the same time, as many of the services work with irregular schedules, 24 / 7.
What a normal PAX sees is may be 5 to 10% of the total spaces arround, and has no idea of what goes on behind the scene... so I'll reveal some to you...
In the next post, more on three of the most important actors: Airline - Airport - Air traffic control. The three A, with A lot of conflicts.
There are certainly bigger companies employing more people, but remind that an airport is not made of a single company, but many of them, typically including:
-Airport authority
-Air traffic control
-Airlines
-Police
-Firemen
-PAX security
-Handling (check-in and boarding)
-Fuel companies
-Catering
-Planes cleaning
-Aicraft maintenance
-Medical services
- ... and I probably forgot many.
and for most of these activities, airports have various companies offering services. Moreover, most airports are now shopping centers as well. A typical mid-size european airport (taking away Heathrow, Frankfurt, Charles-De-Gaule and Madrid) has something like 10'000 to 25'000 on site workers. Hopefully not all at the same time, as many of the services work with irregular schedules, 24 / 7.
What a normal PAX sees is may be 5 to 10% of the total spaces arround, and has no idea of what goes on behind the scene... so I'll reveal some to you...
In the next post, more on three of the most important actors: Airline - Airport - Air traffic control. The three A, with A lot of conflicts.
Welcome to the airport
I've been working in air travel industry for years now, and disucssing about it with familly and friends always raises tons of questions, and a strong interest. Sometimes I also take them with for a visit of the "airside" part of the airport, and this is a great moment each time.
There is something magic in airplanes, airports, pilots, cabin crew, control tower, and air travel as a whole... To be honest, I feel this as well, despite being in this business for quite a while.
My purpose here is to share this magic with the readers, and to give them an insight view of daily life in an airport.
For obvious and sad security reasons, I can't give any people name, or place, date, company name, but the air travel magic is beyond time, so it should not be problematic.
So, I'm happy to welcome you on this blog, and hope you'll enjoy it.
There is something magic in airplanes, airports, pilots, cabin crew, control tower, and air travel as a whole... To be honest, I feel this as well, despite being in this business for quite a while.
My purpose here is to share this magic with the readers, and to give them an insight view of daily life in an airport.
For obvious and sad security reasons, I can't give any people name, or place, date, company name, but the air travel magic is beyond time, so it should not be problematic.
So, I'm happy to welcome you on this blog, and hope you'll enjoy it.
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