In its final report on the Germanwings crash last year, French accident investigation agency BEA has pointed out the previously unstated (if obvious) fact that having two pilots in charge of an airliner may be a defence against the physical incapacitation of one of them, but it is not a guaranteed defence against pilot mental incapacitation.

This is an official acceptance of the fact that one of the industry’s primary fail-safe provisions for the safety of airline passengers can be rendered invalid under those circumstances.

The report, published today, removes any doubt that might still have remained about why the aircraft crashed. There was nothing wrong with the aeroplane or its systems, it states, and the copilot crashed the Airbus A320 deliberately by preventing the captain from re-entering the cockpit after taking a toilet break and programming the autopilot to aim the aircraft at the ground in a rapid descent.

So that’s that.

But can something be done to prevent such an occurrence? The BEA thinks so.

Unusually for an accident report, the recommendations are nothing to do with the aircraft or with operational procedures, and all to do with the detection and mitigation of the effects of pilot mental health.

Briefly, it says, it would be pointless and ineffective to submit all pilots who have no history of mental health issues to regular psychological or psychiatric tests. But at the time any pilot begins to train for a commercial pilot licence, says the BEA, the individual’s entire medical history – including mental health issues – should be scrutinised, and re-examined periodically.

A history of some forms of mental illness need not, alone, become a barrier to progress as a professional pilot, says the BEA. But where there has been a record of – say – depressive illness, that should become part of the pilot’s regular medical review, and if necessary the required regularity of review could be increased.

One of the things that prevented Germanwings, in this case, taking precautionary action regarding their copilot – who had a known history of depressive illness – is the existence of German law regarding medical confidentiality. The airline was not informed that the copilot had received recent treatment, advice and medication because of a return of his depressive state.

The BEA says law must be changed to allow medical doctors to breach confidentiality where patients with safety-critical jobs are concerned if the public might be endangered.

It also appeals for a statutory basis for systems of peer review to be set up at airlines. This is not a new idea and is just plain common sense, but most airlines do not use it.

The safety agency also wants airlines to do something about the state of affairs that, it reckons, prevented this copilot approaching his airline for help following medical advice: the fear of losing his livelihood.

Frankly, what it recommends is that airlines should be good, caring employers of their pilots, and play an active part in fostering their wellbeing.

That sounds like a good idea for any kind of business where safety-critical employees are concerned.