Now, we know more about the most tragic aviation accident of recent years. The report by India’s Aircraft Accident Investigation Bureau (AAIB) about the June 12 fatal accident of a Boeing 787 raises new questions.
The careful wording of the preliminary report[1] is eminently sensible. The facts are what they are, but it remains difficult to construct a scenario around these facts. I suspect that all the parties involved in this fatal accident investigation had a hand in ensuring that the words used where as clear as can be at this early stage. As I said, the facts are what they are.
It’s good that the report shuts down some of the fervent and erroneous speculation that was filling the international media. For this accident, fuel supply being the substantive issue, decisions around flying controls and other aircraft performance issues can be put to one side.
The crew encountered, or were responsible for a situation that once established led to one inevitable sad outcome. The time available to react, at such low altitude, was less than that which was needed to continue a safe flight.
A focus at this point is on the Boeing 787 aircraft’s fuel control switches. These switches are installed in the flight deck and used by a pilot to cutoff fuel to the engines. When correctly installed, these fuel control switches have a locking feature to prevent inadvertent operation.
Clearly unintended switch movement between the fuel supply and fuel cutoff positions can be hazardous. Inadvertent operation of one or both switches could result in an unintended consequence, e.g. engine(s) shutdown. What we know is that sufficient fuel was supplied to the aircraft engines to conduct a take-off. Then for some unknown reason that fuel supply did not continue as it should.
So far, the respectable technical speculation I’ve read (pilot and aircraft engineer led), raises a limited number of possibilities.
One being that the crew acted in an inappropriate or inadvertent manner. Another being that the aircraft’s fuel control switches failed or were caused to fail. Another being that aircraft’s fuel control system (including wiring) failed or were caused to fail. The movement of the flight deck switches may or may not have been involved. What we know is that the record on the accident flight recorder shows a condition occurred that should not occur.
There is no doubt that this would have been a highly stressful situation in the cockpit whatever the root cause. Normally, immediately after the aircraft is leaving the runway the pilot-in-command would have no good reason to look at the aircraft’s fuel control switches. They would be looking forward at the aircraft instruments.
We can take it that every aviation authority/agency/administration with a Boeing aircraft on its aircraft register will be closely watching the progress of this accident investigation. Since, to date, no Airworthiness Directive (AD) has been issued, related this fatal accident, it is reasonable to assume that aircraft systems and equipment failure or maintenance error has not been found. That said, it is worth noting FAA Special Airworthiness Information Bulletin (SAIB) No. NM-18-33 dated December 17, 2018.
We cannot rule out the possibility that this fatal accident was intentional. However, in the whole history of civil aviation this is one of the most extreme explanations. Looking at evidence, a situation when a competent and sane pilot is found to choose to act in an irrational manner is hard to diagnose.
POST: Just over 3-years ago, I wrote “The case for video”. That case to update the rules is now stronger than ever. The case for video.
[1] https://aaib.gov.in/
John Vincent 