Archives For Germanwings

Interesting documentary on SBS about the Germanwings tragedy, if you want a deeper insight see my post on the dirty little secret of civilian aviation. By the way, the two person rule only works if both those people are alive.

The enigmatic face of HALThe problem of people

The Hal effect, named after the eponymous anti-hero of Stanley Kubrick and Arthur C. Clarke’s film 2001, is the tendency for designers to implicitly embed their cultural biases into automation. While such biases are undoubtedly a very uncertain guide it might also be worthwhile to look at the 2001 Odyssey mission from Hal’s perspective for a moment. Continue Reading…

Comet (Image source: Public domain)

Amidst all the soul searching, and pontificating about how to deal with the problem of pilot’s ‘suiciding by airliner’, you are unlikely to find any real consideration of how we have arrived at this pass. There is as it turns out a simple one word answer, and that word is efficiency. back when airliner’s first started to fly  they needed a big aircrew, for example  on the Comet airliner you’d find a pilot, copilot, navigator and flight engineer. Now while that’s a lot of manpower to pay for it did possess one hidden advantage, and that was with a crew size greater than three it’s very, very difficult (OK effectively impossible) for any one member of the flight crew to attempt to commit suicide. If you think I exaggerate then go see if there has ever been a successful suicide by airliner where there were three or more aircrew in the cockpit. Nope, none. But, the aviation industry is one driven by cost. Each new generation of aircraft needs to be cheaper to operate which means that the airlines and airline manufacturers are locked in a ruthless evolutionary arms race to do more with less. One of the easiest ways to reduce operating costs is to reduce the number of aircrew needed to fly the big jets. Fewer aircrew, greater automation is an equation that delivers more efficient operations. And before you the traveller get too judgemental about all this just remember that the demand for cost reduction is in turn driven by our expectation as consumers that airlines can provide cheap mass airfare for the common man.

So we’ve seen the number of aircrew slowly reduce over the years, first the navigator went and then the flight engineer until we finally arrived at our current standard two man flight crew. There’s just one small problem with this, if one of those pilots wants to dispose of the other there’s not a whole lot that can be done to prevent it. In our relentless pursuit of efficiency we have inadvertently eliminated a safety margin that we didn’t even realise was there. So what can we really do about it? Well the simple ‘we know it works’ answer is to go back to three crew in the cockpit, which effectively eliminates the hazard, of course that’s also a solution that’s unlikely to be taken up. In the absence of going back to three man crews well, we get what we’re currently getting, aspirational statements about better management of stress and depression in aircrew, or the use of cabin crew to enforce no go alone rules. But when that cockpit door is closed it’s still one on one, and all such measures do in the final analysis is reduce the likelihood of the hazard, by some hard to quantify amount, they don’t eliminate it. As long as we fly two man crews behind armoured doors unfortunately the possibility and therefore the hazard remains.

Happy flying 🙂

Germanwings crash

Another A320 crash

25/03/2015 — 4 Comments

Germanwings crash (Image source: AFP)

The Germanwings A320 crash

At this stage there’s not more that can be said about the particulars of this tragedy that has claimed a 150 lives in a mountainous corner of France. Disturbingly again we have an A320 aircraft descending rapidly and apparently out of control, without the crew having any time to issue a distress call. Yet more disturbing is the though that the crash might be due to the crew failing to carry out the workaround for two blocked AoA probes promulgated in this Emergency Airworthiness Directive (EAD) that was issued in December of last year. And, as the final and rather unpleasant icing on this particular cake, there is the followup question as to whether the problem covered by the directive might also have been a causal factor in the AirAsia flight 8501 crash. That, if it be the case, would be very, very nasty indeed.

Unfortunately at this stage the answer to all of the above questions is that no one knows the answer, especially as the Indonesian investigators have declined to issue any further information on the causes of the Air Asia crash. However what we can be sure of is that given the highly dependable nature of aircraft systems the answer when it comes will comprise an apparently unlikely combinations of events, actions and circumstance, because that is the nature of accidents that occur in high dependability systems. One thing that’s also for sure, there’ll be little sleep in Toulouse until the FDRs are recovered, and maybe not much after that….

Postscript

if having read the EAD your’e left wondering why it directed that two ADR’s be turned off it’s simply that by doing so you push the aircraft out of what’s called Normal law, where Alpha protection is trying to drive the nose down, into Alternate law, where the (erroneous) Alpha protection is removed. Of course in order to do so you need to be able to recognise, diagnose and apply the correct action, which also generally requires training.