I am a professional pilot and do have training in Failure Modes Effects and Criticality Analysis (FMECA), Certification standards systems failure analysis. I have had to deal with specialist designers who have had more knowledge in their little fingernails than I have in my being on their particular area of expertise (even though I am one of the most highly qualified engineering pilots in the UK).
What some of my colleagues do not realise is that the crew manuals they read are.
1. Written by generic technical authors with little specific systems knowledge (in comparison to their specialist design colleagues).
2. Are, in any case, the "Ladybird book" of aircraft systems (a typical airline 2Systems Description Note for Chapter 28 (Fuel) will take up a couple of metres of shelf space in A4 format). My pilots tech manual (fuel section) has around 0.25% as many words and pictures as the designers reference manuals.
3. As well as being simplified there are often errors in the diagrams and text of our Tech manual "bible".
If anyone wants to kid themselves that they understand the complex interactions in a multiple failure case (especially management fleet managers) then I hope you never have to defend your position in court. Yes there are circumstances where we might have to make a judgement call (where the QRH leaves you stranded) but that is the only time you should ever go outside the designers instructions. QRHs are rigorously checked by experienced design specialists (lip service is often paid to pilots tech manuals).
