The black-box is orange

Each time an aviation accident occurs, the media talk about the black box. This is always presented as kind of a magic tool to solve all issues with the investigation. As I already mentionned in previous posts about the TAM crash in Sao Paolo and others, life is not so easy, and I'd like to unveil some of the black-box mistery with this post.

First of all, there are two black-boxes, not one. The first one is the "Cockpit Voide Recorder", and its name is quite self explanatory. It just records all voice communication, as well as cockpit noises. It can help to explain the human factor part of an accident.

The second one is the "Flight Data Recorder", or more recently, "Digital Flight Data Recorder", or DFDR. This one records several parameters, including but not limited to:
1) Air parameters (speed, altitude, ...)
2) Aircraft configuration (flaps position, gear position, control column inputs, control surfaces position)
3) Engine parameters (power, pressures, temperatures, ...)

Depending the type of operation and the number of seats of the aircraft, it can be mandatory or not to have CVR, FDR, or both. On modern airliners, there are also technical recorders, called "Quick Access Recorder", or QAR, which are used by maintenance teams to monitor the technical status of the aircraft.

If you want to know more about FDRs, the french incident investigation burea produced a very good report about them, including details of their functionning, regulations, and some pictures.

Oh, and by the way, the black-boxes are orange, so as to be easier to locate for rescue / investigation teams. They are in protected cases, supposed to resist a crash, but it frequently happens that they get damaged. This was particularly true with the magnetic tape ones, where the tape tended to melt, or to be damaged by sea water.

It is also quite frequent to not have the very last seconds of recordings, because of communication failures between the aircraft and the recorder, in case the aircraft is broken up, or if electrical cables are damaged by overloads.

The analysis and transcription of black-box contents can be done only be certified and assermented officers.

To close this post, here is a link to the French air incident investigation bureau website, listing some other equivalent organisations. From here you can find many investigation reports. And please remind that these reports are the only one holding established facts. All the rest is journalist work as its best.

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.

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...