PlasticPilot.net

The recent accident with the chinese Boeing 737 that was destroyed by fire in Osaka is a good opportunity to talk about what the authorities are doing when a technical risk is discovered.

The Federal Aviation Administration, which regulates the civil aviation in the USA, recently issued a paper called “Airworthiness Directive”, or AD. This paper describes a problem, and a way to identify and / or solve it.

Each time a national authority publishes an AD, it’s sent to all companies operating the concerned type of aircraft, as well as authorities of other countries for similar action. It is then the airline responsibility to comply with the AD.

Depending on how critical the problem is, an AD can be mandatory or not, and the authority can also publish a due date for its application. Any company not complying takes the risk of severe fines, and possibly withdrawal of operation certificates.

In this particular case, the AD is about a nut located close to the slats (the part of the leading edge that is mobile, helping to generate more lift at low speeds), which can apparently fall, and then perforate the fuel tanks. Yes, just in case you don’t know, the fuel tanks are in the wings. Here is the link to this particular AD: B737 AD2007-18-52.

As you will see, it contains a description of the problem, and a way to check and solve it. The delay is 10 days, which is quite short

This AD system ensures that any potential problem will be fixed on all planes of a given type, and that no operator would be tempted to “hide” events, making the whole system unsafe… even if the flames in Osaka would have been quite hard to hide.