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CAANZ - DESIGN DELEGATION HOLDERS CONFERENCE 2012. Meanderings of an old Engineer’s mind. By Graham Murphy. My background. NZ BE (Mech) 3 yrs ANZ redesigning light aircraft. 3 years UK aircraft industry. Stress Engineer Handley Page & Hawker Siddeley.
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CAANZ - DESIGN DELEGATION HOLDERS CONFERENCE 2012 Meanderings of an old Engineer’s mind. By Graham Murphy
My background • NZ BE (Mech) • 3 yrs ANZ redesigning light aircraft. • 3 years UK aircraft industry. Stress Engineer Handley Page & Hawker Siddeley. • 11 years Technical Services Air NZ Mk 1 & Mk 2. • 8 yrs Consulting in NZ aircraft industry. • 3 years Malaysian Airlines System • 2.5 years CDE first Malaysian light aircraft project. • 14.5 years Safe Air Ltd, including 18 months Connecticut on SH-2G mod design.
MY AREAS OF CONCERN. • Conferring • FPP • Statements of Compliance • Design Changes Special category aircraft.. • Training. • Some Structures Issues.
CONFERRING • IMHO we don’t make a good enough job of conferring nationally on aero engineering issues. • Having said that I recognise the excellent presentations offered by ANZ, but not much use outside of Akl or ChCh. • Back in the 1980-90’s on 2 occasions we had a succesful “technical day” at the RAeS annual conference, but this seems to have fallen out of vogue.
FIT & PROPER PERSONor is that “First Past the Post”? • In my experience reliance on the current FPP concept wouldn’t have stopped the few unprofessional behaviours that I saw first hand. • One has to wonder what the current system achieves. • I have seen several approved MOT2186 forms (old 337) from >1 DO with absolutely nil backup documentation. • I have seen several DO approved packages that were “full of holes”. (As were no doubt some of my older ones).
STATEMENTS of COMPLIANCE • IMHO the SOC is just as important as the 337 form! • If the SOC is garbage the 337 is too. • There appears to be a lack of status associated with being an SOC signatory compared with holding a Design approval. • There is a lack of industry stds & training for SOC candidates. (except within ANZ for their staff & naturally ANZ oriented).
STATEMENTS of COMPLIANCE (Contd) • There is a need for an SOC equivalent formally recognised by CAANZ for non TC products, e.g Special category aircraft. e.g. IPENZ CPEng (Aero) signature on a Design Certificate. Which leads to; • Design Change for Special Category aircraft. I find the current rules on when/if these require approval rather vague on this, must be thick old me… Doesn’t help that the AC is way out of phase with the rules. • Please don’t tell me that the current rash of Special category rebuilds are not full of Design Changes, or is that “design interpretations”.
Training.My favourite hobby horse. • NZ should offer postgraduate “conversion” training for Engrg grads to convert to Aero in their discipline. (e.g. Origins of UK Cranfield course). • We should NOT import people at great expense, or travel overseas, for training that could easily be offered in NZ. • I have concerns that the popular “Repair Design” courses are no substitute for proper design Engineering training. I have never attended a repair design course (some may say that it shows in my work). • Until there is mandatory training for Technicians in the “Raison d’etre” behind airworthiness design rules the frequent negative attitudes exhibited by many LAME’s will continue to exist.
Structural Issues.(Real engineering). • Non linearities. Be aware of them. • Factoring Margins of safety (or R.F’s if you are British). Can be optimistic or pessimistic. Use of term “Apparent MS”. • Interpretation of FAR’s on Ultimate vs limit loads for structures exhibiting non linear behaviour • Secondary affects of deflections.
DVa Wing FEA • Flexibilities of external bracing. • Flexibility of internal bracing. • Affects of lateral stiffness on Cabane strut loads. • Parametric Study carried out.
FINIS “Engineering is the art of moulding materials we do not fully understand into shapes that we cannot precisely analyse when subjected to forces that we cannot really assess in such a way that the community at large is not aware of the extent of our ignorance.”
