Flight Testing

[BWBriscoe]

Before an aircraft manufacturer, say Airbus, delivers an aircraft to an airline, what sort of testing of the aircraft is carried out in the air?

For example, before Airbus delivers an A330 to say Northwest, what testing will be carried out by Airbus pilots and engineers with the aircraft actaully in the air?

[ICT_SLB]

You have to remember that the production flight test is only the last procedure of a whole series of system and operational tests done on each aircraft while it is being assembled. This will include full engine and electrical & radio checks plus a test of fuel quantity & flow in a specialized facility.

The actual Production Flight Test is carried out by a minimum crew (typically Pilot, Co-pilot & FTE) who all have many hours on type and are well acquainted with the "normal" characteristics. The test includes sub-sections for takeoff, climb, descent, approach & landing where specific tests are carried out. If the aircraft is equipped with APU and/or RAT then these are also exercised as is manual deployment of gear, manual reversion etc. Post-flight the FDR & CVR will be downloaded & checked.

This is only skimming the surface - the test for even an Regional Jet is over 18 pages and only gives the outline of the tests required as the crew is expected to know most of the details!

[safetypee]

For larger (long range) aircraft the production flight tests could be undertaken during one flight or even amalgamated with delivery to a cabin completion centre. In my experience in the regional market a minimum of two flights were flown and a third snag clearance flight always planned before the aircraft was offered to a customer. Few if any major issues were found during flight test; although I do recall a complete air-system failure, no anti icing, and stuck flaps on one first flight. Generally the performance tests confirmed the certification requirements and compared with the type database which validated the build quality. The snag clearing flight was always a point of debate between production, ground and flights test, and the bean counters. For late production run aircraft (after the first 50) the production tests could easily be completed in two flights, providing the aircraft was complete. However in order to meet late customer requests, the advent of ‘just in time’ (always late) build policy, and need to meet set dates (keep the shareholders happy), the first flight was often undertaken with acceptable discrepancies (mainly in the cabin).
On rare occasions (large powerful customers) operator pilots participated in the production tests; the aim was to satisfy the customer and speed the acceptance process. This policy was fraught with problems; most line pilots had not experienced a flight test environment before, you cannot test fly an aircraft within airline SOPs. Furthermore the experience of operator pilots was variable; the presence of some on the flight deck was more hazardous than the test it’s self i.e. those who had not conducted a full stick push stall, or real engine out climb before. It was somewhat surprising to find so called experience pilots from leading aviation countries who had not stalled a large aircraft, flown with one engine shut down, or even exceeded 45 deg bank; and then there were those who though that the aircraft would disintegrate at VMO +5 !!!
Latterly common sense prevailed and customers were given up to 5 hours flight time for their acceptance against their own (usually very restricted) test plan. During this time flying with operator pilots enabled a positive transfer of knowledge about the aircraft, particularly where the manufacturer used training captains as production test pilots.

[Genghis the Engineer]

I know little or nothing about airline operating environments, so can only really comment on what we do in the little aeroplane world - but it might nonetheless be interesting to you.


Generally for a series aeroplane, we'll fly three sorties of testing - typically totalling 2-4 flying hours. These sorties are:-

- A shakedown, normally at moderate weight with minimum crew to check all the main systems are working as advertised. If problems are found, this sortie may be repeated several times until it all works.

- A heavyweight sortie (normally at-least 95% MTOW), ballasted to the furthest forward CG reasonably achievable (which can actually be fairly aft since that's where the cargo/pax go). This will be used for performance checking (particularly climb rates with various safe engine combinations and Vh), and the heavyweight handling - roll rates, pitch authority at low speed, various stalls.

- A lightweight sortie, at the furthest aft CG achievable, this is generally the worst condition for handling so various stalls, extreme attitudes, etc. will be flown as well as usually a check on any known marginal-handling points in a particular envelope. (These schedules are usually standard to type, with maybe a few tweaks introduced by the project FTE according to build standard).


The first two sorties - shakedown and MTOW-fwd may often run into each other since sorting system problems out, if the aircraft has initially been shown "safe to test" can often be slotted into the high weight sortie rather than introducing other single-purpose flights.


One thing I do recall about the big-aeroplane world was a conversation I once overheard with the CTP of Airbus around 1996. He said that he expected each production FTE (and bear in mind they do the majority of the planning and reporting work, not the TP) to clear-through about 18 aircraft per year. That would probably work out at 2-3 weeks work per engineer to clear through each airliner.

In the little aeroplane world, I generally would expect to put around 1-2 weeks in if I'm acting as FTE for the job and it's a straightforward series aeroplane, which seems reasonably proportional since the singles and medium-twins that I work on have rather less complex systems to worry about.

G


N.B. I'm also not a fan of the use of non FT trained pilots in this context, the lack of understanding of flight test reporting in particular. Having said that, mixed TP/operational pilot crews can often work well and save test pilots having to maintain full currency on each type. Also, it is (whatever the ETPS/EPNER Mafia will have you believe) not all that hard to take an able and experienced pilot and train them to do this sort of flight testing - particularly if they are working with an FTE.

[212man]

Can't comment on fixed wing but in my experience accepting Eurocopter products I was presented with accepting aircraft which had been fully post production tested by their own production test pilots. These guys had done an abridged TP course at EPENR and flew with FTEs over about 12 hours or so (would vary with type I guess).

Customer acceptance is generally supposed to be a formaility and done by the company's Chief Type Captain alongside one of the PP TPs or Instructor as the a/c commander (still restricted F reg). Any snags are then corrected before final acceptance. In some cases (normally private owners who don't feel qualified to assess) the acceptance is purely done by the manufacturer.

[LOMCEVAK]

Genghis,

There have been some very good, informed replies made on this thread. Therefore, I am appalled that you, as a moderator, should make flippant, derogatory comments such as:


"....whatever the ETPS/EPNER Mafia will have you believe....".

That was very unprofessional, especially on this forum, and I feel that you need to justify yourself and present the data that supports this conclusion!!!

For those who have no knowledge of ETPS, they do not train, nor never have trained, pilots specifically for Production Flight Tests. Their Graduate course trains experimental test pilots and flight test engineers, and selects people for the course based on their experience and ability. I can assure you that the same philosophy and process would apply at ETPS to training crews for any form of flight test activity. I believe that EPNER did, at one time, run a course in training flight test crews to perform post production flight test although I am not sure if they still do. Perhaps someone could comment, and on the fact that their attitude towards this training was very professional, without any of the prejudice that you imply.

Out of interest, ETPS do run a groundschool only course for the UK Services on Post Maintenance Flight Testing, and this is recognised as a separate skill from experimental flight test. In fact, Boscombe Down has specific named pilots for performing post maintenance flight tests on its own aircraft, as many of the test pilots who carry out the experimental flight test work do not have the in depth experience on type that is required for performing such checks.

Flight test revolves around integrity and supportable opinions. Can this forum stick to those principles please, especially by the moderators!!!!

[Genghis the Engineer]

It happens that in most non-military environments anybody qualified as a TP is also qualified as part of that route to carry out periodic or post maintenance air tests. When I worked at Boscombe (as an FTE, in fact I suspect that we have flown together), post maintenance air tests (which I did run on occasion) were flown by a convenient TP qualified on type. I wasn't aware that had changed or possibly that the situation was never adequately explained to me and I just got lucky each time I asked for pilots for the task?

There are organisations - such as Airbus or UK-CAA who seem very reluctant to employ non TPS graduates despite both UK and France having industries who in large part use non-graduate TPs who have worked their way up (OK, the UK hasn't much of an industry left, but of I think 9 F1 B-conditions organisations, I'd guess 5 don't have use of a TPS graduate). To be fair to those who do, employing a graduate is pretty much a certainty of competence, and you really need to spend time and money assessing a non-graduate - which may be the reason.

The use of the term "Mafia" is tongue in cheek and I apologise if I've caused offence (remember when half the senior staff of the scientific civil service seemed to be Welsh - they were termed the "taffia mafia" I intended a similarly light context), but nonetheless organisations run by TPS graduates are noticeably reluctant to recruit non-TPS graduates. ETPS itself, when I went through the course, had no TP or FTE tutors who weren't TPS graduates.

G