For an aviation industry that takes pride in learning lessons from experience and taking timely corrective action, a series of operational events is surprising to say the least.
Today’s large aircraft do look much the same. The tricycle undercarriage has become universal. A set of steerable wheels at the front and a heavy set of landing gear, each side, to the rear. When parked, a nose gear collapse or inadvertent retraction on a large aircraft is not catastrophic. The aircraft can be recovered, inspected, and repaired. This undesirable event can be dangerous for anyone in the vicinity. It has the potential to be fatal. Fortunately, so far, there has been no fatalities.
For an aircraft operator such an event at an airport gate is a massive expense. Putting an in-service aircraft out of action for a considerable time.
To date, several damaging nose gear collapse (and alike) events have occurred to large aircraft[1]. Detailed analysis of these events exists and corrective actions are proposed.
One conclusion is to say that this is about people not following procedures. That is the instruction is to put a pin in one place but instead it gets put in the wrong place. So, this dramatic unintended event is written up as a maintenance error. It’s an outcome that no one intended. That’s fine. There’s no doubt that an error was made. Accepting that an error occurred is not a reason to blame. That is if there are no signs of negligence.
The trouble is the simple question – how easy was it to make that error?
Then we get into that grey area of the gap between aircraft design and operations. In a design office it may be reasonably assumed that a procedure will be followed in an almost robotic manner. No need for the people in operations to think beyond taking the same action day-after-day. This would surely become widespread practice.
As we know the actual environment of aircraft operations can be more demanding than the original equipment manufactures might imagine. Pressure to turn around an aircraft can be high, working conditions can be poor and fatigue can play a part.
There are lines of communication between the aircraft design and operations organisations, and such difficulties are regularly discussed.
Faced with an event categorised as maintenance error then what next? Redesign the aircraft? Change a procedure or require more training? Those are three of the options, there are more.
This is where the possible discussion gets reactive. Now, it would be extremely costly to redesign an aircraft for the sake of an event that is rare or for which the consequences are minor. It is possible to put numbers on each of these. The rarity, the cost, and the impact.
Modifying or rewriting a procedure, on the other hand, can be less costly and it may be quite sufficient as a corrective action. That said, any procedure that can be written can be subject to error. In fact, the original procedure may have been straightforward and well thought out.
Then there is the fall-back position. Give the people in aircraft operations more training. The assumption being that more training means less errors. It is a crude assumption because this is not a linear relationship. So many other factors come into play.
Discussions surround the above possibilities can become protracted. There’s a call for more analysis and more data. There’s the proposal for a study to be conducted. Once in that loop a year can go by as if it was a month.
There’s always the argument that highlights dozens of aircraft operators haven’t had this event occur and therefore the finger is pointed at those who have. This argument gets an outing, but it is foolish. It’s like saying – I haven’t had an accident yet, and therefore I’m safe. Foolish.
There are a lot of detailed discussions and a million and one opinions. Taking the big picture, this is a problem that is solvable[2]. What is surprising is the reoccurrence of the problem.
[1] https://www.gov.uk/government/news/aaib-special-bulletin-g-zbjb-inadvertent-nose-landing-gear-retraction-during-pre-flight-maintenance
[2] https://www.federalregister.gov/documents/2019/12/12/2019-26734/airworthiness-directives-the-boeing-company-airplanes
John Vincent 