Evaluating stall characteristics - best procedure?

[CirrusF]

I recently had the interesting experience of sitting in on a preliminary evaluation of a light aircraft (DA42) by a French military test pilot at CEV Istres. One of the checks was on the stall characteristics.

I was interested to observe that the TP seemed to pay no attention to holding the altitude steady in the approach to the stall, and the stall characteristics (both clean and in landing configuration) were recorded when we were in a descent of around 700fpm. He appeared to keep the stick deflection constant as the stall approached.

This seemed odd to me (as just a CPL) as in all the training I have ever been subjected to, I have been told to maintain altitude until stall, requiring a rapidly increasing stick deflection as we go down the wrong side of the lift/drag curve.

As a frustrated wannabee test pilot I'd be grateful for any comments!

[sycamore]

CirrusF, the difference is that the emphasis on maintaining height /minimising height loss at/beyond the stall is a training requirement,not an `absolute numbers` requirement as in stall testing.
For stall-testing it is necessary to stall the aircraft in a configuration(clean/gear flaps etc) as close to 1g as is possible,with in most,but not all configurations,zero thrust/torque(props)/idle thrust(jet) as is possible,and this will mean in a shallow descent.
The approach to the stall is usually started at about 1.3-5 Vs depending on type/configuration,and then the a/c is slowed down at a rate of speed reduction of between 1-2 kts/sec. whilst noting all the effects,ie buffet onset,aileron `*******`/snatch,yaw,nose slicing,pitch-up,buffet,control activity/position/forces,etc,etc,same with ASI/Vibrations ,etc. Then one looks at the stall `break`,clean,nose dropping,wing-drop,yaw,or is it a `pussy-cat`? Then you go and do it all again to be repetitive/consistent,then at all CofG positions,fuel loads ,etc.
That`s a rough-guide;it also should be noted that the instrumentation in the aircraft should have been calibrated if /wherever possible,otherwise one can be wasting a lot of effort.
Hope that helps..Syc..

[barit1]

Speaking as a retired instructor and CPL, remembering my own experiences...

Are cross-controlled stalls normally investigated during flight test? When I had 50 hrs or so I was checking out with an instructor in an old Ryan PT-22 WWII trainer. He had plenty of experience in the type, and asked me to try a power-off stall with a bit of slip. The result - a very rapid snaproll (flick if you like) 1 or 2 knots above Vs. No warning at all. At low altitude it could be deadly.

Other than that, the PT-22 was a very likable ship.

Link to Barit's picture (http://www.warbirdalley.com/images/PT-22-aerial-01-comp.jpg)


(Post edited by moderator because of over-large photograph - you can still look at it by clicking the link above.)

[Pugilistic Animus]

I wish they could all snap so easy:ugh:

or is it me:uhoh:

great story Barit1

PA

[Tee Emm]

You would think if the bloke in the front cockpit couldn't afford a crash helmet he could at least wear one of those elongated perforated head gear used by cyclists. Might even get a couple of more knots because of reduced drag:ok:

[Genghis the Engineer]

Back to Cirrus' original post.


There seems to me to be a definite mismatch between...

TP: "1kn/s decel, as close to 1g as possible, identify the stall and stall warning characteristics and document them"

Instructor: "minimise height loss, whatever decel rate goes with that, stall warning is audible or very clear buffet - nothing else counts, stall is marked by a pitch break, if you don't get one, pull back harder on the stick".


In the military flight testing world, there's a concept called "role relation" - where test methods and evaluation are modified to match the way the aeroplane will be operated in service. UK CAA has always insisted that it's light aircraft Test Pilots are also FIs of some description, giving them the ability to role-relate, in the same way that a military TP who was recently a fighter pilot can reasonably assess a new fighter aircraft.

However, in my experience, a large proportion of TPs assessing light aeroplanes likely to be used for civil instruction are not FIs. This is arguably a deficiency, and perhaps is at the root of Cirrus' observations? Whilst the 1kn/s certification stall is certainly still needed for various reasons - such as the determination of Va, you could make a strong case that stalls similar to those in the PPL and CPL skills tests should also be flown as an exercise in role-relation.

Of course, most (all?) civil licenced TPs have at-least taken these tests, if not taught for them, which should give that understanding. But perhaps the military TP who Cirrus was flying with had not?

Ref: Barit's post - perhaps this is a role-relation issue also? In most aeroplanes, a snap role would not be a normal manoeuvre, and probably not even a reasonably expected bit of mishandling. In an aerobatic aircraft however, it would be, and I'd certainly hope to see it assessed. That test plan determination surely comes down to the knowledge of the test team, and in particular the test pilot(s) to get right?

G

[John Farley]

Whoa chaps.

I think some of us are confusing two very different topics here.

A. Getting useful and repeatable data regarding the stalling characteristics of an aircraft that is under test. This data will be needed for certification (whether the aircraft is mil or civ). Indeed many aspects of the service operation of the aircraft will be determined from this data – such as the certificated approach speed which will be 1.3 times one (just one) of the very many different types of stall that will be tested.

B. Teaching students (mil or civ) to recognise a stall and how to deal with it confidently and safely then during later stalling exercises doing everything as efficiently as possible (this last word requires minimisation of height loss).

Good accurate and repeatable flight test data (on any topic not just stalling) requires that all parameters are as nearly constant (steady) as possible. In the case of basic stall data we want the angle of attack that is reported against some other parameter like g, bank angle, buffet onset, wing drop, nose drop etc to be as constant (steady) as possible.

Big point: the only things that affect the way the air flows round any aircraft that is well subsonic (in whatever configuration it happens to be in) are the angle of attack and angle of sideslip.

So to get data for case A above we need both AoA and sideslip angle to be as steady as possible. Eg “With zero sideslip the AoA was 12 at buffet onset, 13.5 at first lateral stick snatch, 15 when the nose dropped or 16 when the stick reached fully back (or whatever all the numbers/events are as the ones I have quoted above are of no significance whatsoever)

If you allow me to bang on a bit longer about flight test techniques I hope it will become clear why I later say what I do about topic B.

A comprehensive stalling flight test programme requires a huge number of different stalls to be flown. There will be one set for each configuration typically TE flap angle LE device setting (if fitted as they say in the car handbooks) undercarriage position and most importantly they will all have to be looked at under different power settings to say nothing of CG, weight and altitude. If your aircraft can exceed about Mach 0.5 then throw in a whole lot more at different mach numbers.

But that is FAR from the end of the flight test stall programme. Once that is done there will be many more stall entries to be done with a rapid onset of angle of attack (now we are starting to get to the case B above)

Here the tp wants to establish what will happen in the unsteady case and is covering the flying club type of training stall or if you like the way a pilot might accidently blunder into an inadvertent stall. Necessarily if you close the throttle in level flight and then hold your height your airspeed will reduce quite quickly and very importantly your angle of attack will increase ever more quickly. Indeed this approach will likely produce quite a big AoA overshoot once the stall happens and before the student starts the ‘recovery’. The IAS will likely get to a silly low value and whatever reading it gets down to is likely to be pretty meaningless due to unknown pressure errors in these transient conditions.

So if you speak to a tp and he mutters about ½ to 1 kt/sec and also says he ignores the flight path (which does not affect the airflow round the wing) he is talking about how he gets this nearly steady data and is not describing the stalling programme – just one aspect of it.

Finally any flight test programme fully takes into account the role for which the aircraft will be used. So Cirrus there is no mismatch between what you were taught and what goes on in flight test. Happier?

I could also go on about how you keep stalling flight tests safe (they are by definition being done for the first time) but this post is too long already and there are books on all this.

[Fitter2]

and there are books on all this.

for instance the relevant chapter of JF's excellent book he is too modest to plug.

[Pugilistic Animus]

Well it's definitely ordered for my library

would be helpful when I come up with the cash to go to the Mojave:)

PA

[Genghis the Engineer]

John.F, everything you say is great, except...

... I'm afraid that in my experience the developers and certifiers of light civil aircraft commonly do not fly the sort of extensive test programmes that you are describing.


Here's an example, absolutely true, I'll simply keep the aircraft type to myself.

A few years ago I was asked to go and evaluate a highish performance light aeroplane being manufactured by *****, a small but well regarded company based "somewhere in Eastern Europe". The company held national and German approvals (at the time EASA was still a figment of somebody's deranged imagination - perhaps it still is) and was exporting aeroplanes to a large number of countries.

As part of my assessment I obviously wanted to look at the stall, and as part of the preparation I'd been through all of the company FT reports they'd give me. The company summary was very clear: stall at 64kph, no wing drop, no tendency to spin.

So, there I am - lots of height, spin recovery briefed (I'm not completely daft!), and agreed with my safety pilot (who happened to also be the chief designer) that I'd fly a power-off wings level stall. So, standard stuff - trim to about 1.3Vs, power to idle, keeping the ball in the middle decelerate slowly at about 2kph/s, small control inputs to check effectiveness every 10kph or so... And so, 66, 65, 64, 63, 62, INCIPIENT SPIN. So, I recovered that, and said to my safety pilot "hmmm, that was interesting" (or words to that effect), who agreed and asked me not to do it again.

Debrief points: the company TPs had to meet a local certification requirement that Vs0<=65kph, with no more than 20° of wing drop, and no tendency to spin. So, they'd slowed to 64kph - at which point the aeroplane was clearly still flying unstalled, but chosen to declare that as the stall speed. AND THIS HAD THEN BEEN CERTIFIED IN THREE COUNTRIES LIKE THAT - all of whom I'd regard(ed!) as above averagely competent in aeronautics. And, unwittingly, I was probably the first pilot to take this aeroplane to the aerodynamic stall. (Good news, when it was finally certified in the UK, it had been properly tested and now has, I understand, quite benign stalling characteristics!)


I can think of other instances on part 23 or smaller aeroplanes, but I'm afraid that in my experience the pattern is fairly consistent - certifying authorities do not insist on the sort of thorough assessment that you are describing - and whilst not all, there are companies who will do the minimum to tick the boxes of the certification standard - and in several countries I've worked in (including, sadly, the UK), the national authority will defend and support their decision to work that way.



Having said that, I absolutely agree that a competent military flight test organisation such as CEV or A²E² will certainly make sure that any stalling assessment carried out is thorough and role-related (so far as they use test pilots with the right role knowledge, which is probably easier for them in a combat than a training aeroplane), and also that this "big grid" isn't going to be there for a quick qualeval which is what CirrusF seems to be describing flying in the DA42, where an idle 1kn/s, high RoD stall is likely the major test point in a short but busy sortie.

G

[John Farley]

I guess the world is not perfect Genghis - no matter what area of professional behaviour one looks at.

Returning to the specifics of stalling in the GA community I really do wish that QFIs did demo the gentle and very easy flight test approach before putting students through the 'close the throttle fly level and recover when it stalls' manoeuvre. In my view the latter can result in quite an off-putting experience for a low hour student.

[Shawn Coyle]

Clearly a case where the real world and the flight test world don't speak quite the same language.
There's a whole lot of issues that could be raised about the stall techniques used for testing and those used in the real world. Some of the recent turbo-prop accidents in the US have shown how different the two worlds are.
(and this problem is not just in the FW world - the helicopter world has a number of differences between certification and real world as well)

[Tester07]

So what's the point of your story, Genghis, with respect to the original question?

You flew the aircraft in the traditional manner (just like the French pilot in the question) to determine a certification stall speed and found that the company had apparently not done this correctly. This is obviously not good but I do not see what relevance it has to the original question, as to why the French test pilot may have flown the stall in that manner.

John has of course described the two approaches to stall testing and the reasons for them very well.

Test pilots are taught how to conduct stall testing and determine stall speeds for civil certification or military airworthiness. They are also taught the importance of conducting suitable 'role relatable' testing on any type of aircraft they might fly.

Your insistence on turning any point like this back to your favourite subject of how military test pilots are unsuitable to test light aircraft because they dont know enough about it (or they're not an FI!)is a little boring, and probably quite irrelevant to the original question in this case.

[Genghis the Engineer]

I'm sorry if that's what you thought I was doing Tester 07, I thought I'd got that out of my system a long time ago and certainly didn't intend to make the points you think I am.


My points:

(1) What John says about a complete stalling test grid is a valid description of good practice; but, in my experience a lot of the light aircraft industry doesn't do it that way - often the minimum needed to show standard compliance is all that's done, and that with a certain amount of gamesmanship.

(2) Role relation is very important and flight testers used to one type of flying may need to "buy in" a bit of role relation knowledge when testing for a different role.

(3) The test described by the OP was a standard certification stall, not a role-related test. Both are needed.

(4) There is a mismatch between civil certification standards and the way training aeroplanes are actually flown in deliberate stalling. This is compounded by flight testers in the civil industry who don't construct the sort of thorough test grid that would be normal in the military world.


To be honest, I don't think that you can really accuse my...

I absolutely agree that a competent military flight test organisation such as CEV or A²E² will certainly make sure that any stalling assessment carried out is thorough and role-related

Of being a criticism of military (trained) TPs. My main criticism was of civil certification practice which DOES NOT necessarily apply the rigour, and particularly role-relation, that would be normal to a military-trained flight tester.

And yes, I digressed from the original question - but I'm not alone in that!

Also, for the record, most - quite possibly all - of the key decision makers in the organisations that I'm criticising are not military trained TPs or FTEs.

G

[zzuf]

I think it is important to point out to the original poster that there really are two distinct phases to stall testing:

a. Establish the stall handling qualities, which was the original query, for the many configurations and flight conditions required for certification (ie straight, turning, low/high approach rate, sideslip, high power, etc).

b. Establish the stall speeds which are required as the basis for other performance speeds.

This may be far from a straightforward exercise with an aircraft which appears to be stalling at around the maximum speed permitted by the certification standard yet may need handling fixes which could result in an even higher stall speed.

[Surrey Towers]

Just goes to show that a little knowledge can be a 'dangerous' thing. Perhaps, not dangerous in the accepted sense of the word, but it does show that there are them that really know and them that nearly know. I am sure you know what I mean.

Simple really. But...........I'll have Dunne to Farley et al any day of the week.

[Proof Reader]

Surrey Towers

OK, I will be the brave one then and rise to the bait since no-one else is going to stick their head above the parapet and admit it. I don't understand!

"I'll have Dunne to Farley et al any day of the week"?

[Surrey Towers]

I thought everyone knew that.....J W Dunne, worked out the design for a swept back wing biplane, and built it - in circa 1907. A very clever and brilliant engineer.

In between times the seemingly endless list of the brilliant best of test pilots came and went (indeed, often killed). In my view I think I am right when I say that unless John Farley had not been so skilled as an engineer, as well as a pilot, the Harrier would never have been born.

From Dunne to Farley encapsulates the whole of the major flight testing years - for me at least.

[Genghis the Engineer]

A bit simplistic I'd have thought.

So far as I know, John Farley, whilst a thoroughly talented chap who has done much for British aviation - and continues to, is neither (a) dead, nor (b) designer of the Harrier.

G

[Surrey Towers]

Genghis, where did I say that JF was dead? Where did I say he designed the Harrier? That was done by Dr John Fozard and his team.

However, John Farley's own engineering background, and his flying skills, was a significant factor in its devlopment.

Credit where credit is due.

[Final 3 Greens]

Returning to the specifics of stalling in the GA community I really do wish that QFIs did demo the gentle and very easy flight test approach before putting students through the 'close the throttle fly level and recover when it stalls' manoeuvre. In my view the latter can result in quite an off-putting experience for a low hour student.

I'll second that.

On my first experience of a demonstrated stall, we got an incipient spin and it made me nervous of stalling for quite a few hours afterwards.

[3 Point]

Well, this is an interesting debate!

I'm not a TP but I am and end user of aeroplanes; many different types of aeroplanes. It seems to me that we are having a heated agreement here!

I always thought that our TP colleagues have two very different jobs to perform; sometimes simultaneously, sometimes separately. Fist, how does this machine behave? Second question, is the behavior of this machine fit for its intended purpose?

I'm not, as I said a TP but, I am a fighter pilot, FI, airline captain (depending on the day of the week!) and so, while I have no relevant expertise to contribute to the first part of the TP's job I do believe that my experience is relevant to the second question; is the machine fit for purpose!

Surely, the testing of a new design is conducted from these two differing points of view? As a user I am not particularly interested in the bare bones analysis of a new machine (although I certainly acknowledge the importance of investigating and defining that). Rather, I am much more interested in learning if the new machine will do the job I want to use it for!

Pure flight testing and role related testing should go hand in hand!

With that in mind why would a QFI want to teach a "gentle and very easy flight test approach" to the stall if that is not how it might present itself in normal flight operations? We are not teaching pilots with just 12 hours in their logbooks to fly flight test profiles, we are teaching students to deal with situations they might encounter in normal flight operations!

In my experience a student pilot can cope with all sorts of new and potentially frightening situations if he is properly briefed and prepared for the event; after all, every time we take off I am presenting him with new and potentially frightening experiences! QFIs teach pilots to be prepared for situations which might happen in the real world of flying day to day; not how to repeat flight test techniques which demand deep understanding and very precise and highly skilled flying to create.

I have never had a student who was unduly concerned about stalling because I have always explained what to expect and and made sure that he understood what we were doing before starting the starting the exercise.

There are, in my mind three separate questions...

How does this aeroplane behave?

Is its behavior suitable for its intended task?

How can I best use this machine to teach a student about flying?

Question 1 is purely for TPs; question 3 is purely for QFIs but, crucially, question 2 has to be answered by both together!

I think I have just agreed with JF. Ghengis, I'm sure that you are absolutely right when you say that there are companies who do not thoroughly investigate the behavior of their products but, aren't you saying the same thing as John? TPs need to find out what a new machine does, then asses if it is suitable for the intended purpose? QFIs need to teach students to anticipate and cope with situations they may find in real life day to day flying and, to do this effectively they need to have machines suitable to that purpose.

It is not appropriate for a QFI to teach a new student how to fly a TP investigative technique. We need to teach and fully explain how aeroplanes behave and how to operate them in normal service .

Happy landings to all!!

3 point

[Genghis the Engineer]

I'm pretty certain that I was agreeing with JF about what good practice is (although given his massively greater experience and credibility than mine, I'm not sure that he needs it!), but I was suggesting that not everybody out there - particularly in the light aircraft industry - follows this sort of best practice in ensuring that they include role related test points in a programme.

Any good test programme (regardless of the aircraft type or class) should almost certainly include both "pure" flight testers, and user-operators - often TPs may have that user experience (military flight test organisations usually make very sure of this), but if not it does need to be brought into the test team. But, I think that this is something that's been accepted for a very long time - plenty of test pilot autobiographies have discussed this, for example with Jeffrey Quill's occasional forays to the front line to ensure he knew what current fighter pilots were actually doing with their Spitfires.

I can recall as a student being worried by a few manoeuvres: particularly stalls and spins - perhaps I wasn't well enough briefed, but I don't think so. I agree that students do need to see the worst that the aeroplane may (within reason) do to them, but don't see why that needs to be the starting point of their experiences. A benign idle 1kn/s wings level stall to a mush-descent is surely a reasonable introduction to stalling for a student, even if they'll go rather beyond that before the instructor has finished with them.

G

[Pugilistic Animus]

Genghis ---I agree

further the stabilized stall BEST replicates the conditions experienced on approach to land the worst place to stall--all of the other stuff is to show that a stall can happen at any airspeed at any attiude and any power setting:)

not to scare to warn

PA

[barit1]

Somewhere on Youtube there is a video of new F-16 flt. control software being evaluated. The bird was loaded with asymmetric stores (as in halfway through an air-air encounter) and a high-G stall induced. The bird tumbled (as expected) but was recovered within the desired time/altitude parameters.

A good example of "what if" testing, not terribly different from my PT-22 "test" - although I'm sure the F-16 guy got knocked around quite a bit.

EDIT:
YouTube - F-16 Loss of Control, Test Pilot on Yaw Departure (http://www.youtube.com/watch?v=Rv9YC-gaNYo)

[3 Point]

Hi Genghis,

Yes, I acknowledge that you were agreeing with JF; as I said I think we are all in agreement here.

Your last post above is spot on, particularly the final paragraph. Of course a student needs to be exposed to the range of an aeroplane's behaviors and certainly, it is usually wise to start from the benign and move towards the "interesting" aspects of that behavior! The exact starting point, the rate of progress and the ultimate goal will vary from student to student and the art of teaching is to match the lessons to the student's capacity.

PA is spot on too. The gentle approach to a stall with very gradual rates of change replicates very well an unexpected stall on approach. But the operational pilot needs to be equally well trained and prepared for other situations eg ...

level flight, possibly autopilot in altitude hold, engine failure or autothrust trips off, pilot busy with associated actions does not notice approaching stall ... has happened, will happen again!

Engine failure on climb (in multi engine or, worse single engined aeroplane) pilot focuses on dealing with engine failure, aeroplane approaches stall very rapidly indeed.

I'd slightly amend PA's final comment; not to scare but to educate!

Happy landings!

[wiggy]

genghis

"A benign idle 1kn/s wings level stall to a mush-descent is surely a reasonable introduction to stalling for a student"

As far as I recall it that was pretty much how CFS decreed stalling should be introduced to the stude on the JP3/5...(yeah, yeah I know...) As I recall it the demo was done at the back end of one of the early S&L exercises...Bloggs then did the full Stalling one exercise on the next trip.

[John Farley]

It is not appropriate for a QFI to teach a new student how to fly a TP investigative technique. We need to teach and fully explain how aeroplanes behave and how to operate them in normal service .

3 Point - I don't want to flog a dead horse but I think we might have to agree to disagree here.

My patter is on the lines of "When test pilots are looking at how a new aeroplane stalls they don't like frights so they do it this way (quick demo) which enables them to nibble at the AoA to gently investigate what happens.

However if you (bloggs) should stall by accident then it is likely that you will overshoot to a much higher AoA because of the rate at which you are approaching the stall therefore you must learn what that is like and learn to cope with it" (demo S&L throttle shut) "Not the same eh?" "Now you have a go....etc etc"

[3 Point]

Hi JF,

No objection to using a structured introduction and going from the benign demonstration to the real wold situation involving the more aggressive AOA excursion in the way you describe; indeed this seems an ideal learning process.

Your patter is nice and I've used similar myself, particularly with the nervous student. You will see from my examples above that I advocate teaching staling in realistic scenarios but the gentle measured approach you describe is a perfect introduction.

I was uncomfortable with the comments made earlier in the thread to the effect that QFIs "should teach students to stall like TPs do it and not S&L, idle thrust which is too scary" (paraphrased of course!).

No need for us to agree to disagree ... we are in complete agreement!

Happy landings

3 Point

[Dudley Henriques]

I recently had the interesting experience of sitting in on a preliminary evaluation of a light aircraft (DA42) by a French military test pilot at CEV Istres. One of the checks was on the stall characteristics.

I was interested to observe that the TP seemed to pay no attention to holding the altitude steady in the approach to the stall, and the stall characteristics (both clean and in landing configuration) were recorded when we were in a descent of around 700fpm. He appeared to keep the stick deflection constant as the stall approached.

This seemed odd to me (as just a CPL) as in all the training I have ever been subjected to, I have been told to maintain altitude until stall, requiring a rapidly increasing stick deflection as we go down the wrong side of the lift/drag curve.

As a frustrated wannabee test pilot I'd be grateful for any comments!

Normal flight test procedure for 1g stall at GW both clean and dirty is a fixed pitch rate input (per data card) through to CLmax noting the corrected IAS at the stall.
All other departure test is performed on a step by step process as requested through the engineering data point card.

On teaching stall to students (I've noticed a few posts on this in the thread so will address here)

The problem for instructors when teaching stall to a new student is that the student will learn and retain nothing if under stress or feeling apprehension of any kind. Although some students will take easily to stalls, others require a careful and structured approach to what will be a totally new flight experience for a new student. If the instructor isn't innovative and doesn't take the time to properly prepare a new student for flight on and beyond the left side of the envelope, the result can easily be a student doing the required maneuvers by rote while stressed, and a student highly unlikely to act correctly down the line if actual stall is encountered.
With this in mind, instructors are well advised to recognize that although all stall occurs at the same aoa and the IAS for stall at GW is placarded for Vso and Vs on the ASI, this scenario is for a 1g wings level stall and that almost ALL stall encountered in the real world in actual situations will be accelerated and possibly cross controlled.
The problem for the instructor therefore is to be able to introduce stall gently using the 1g power off level flight scenario allowing the student to build confidence. The instructor should as well during this period, gently build up the student so that the more useful and necessary realm of accelerated stall can be introduced.
If done properly, a good CFI can take a student all the way through a complete stall education without building unnecessary stress levels.
A student trained in this manner will be a better pilot, having a more rounded approach to stall centered around stall occurring at the same aoa but VERY different airspeeds dependent on flight factors.
Dudley Henriques

[barit1]

Dudley makes a good point.

In my case, well before I took formal lessons, I had ridden through many stalls in several different aircraft (that was my dad's way of evaluating whether a plane was "honest" or not). It was no big deal for me - even if we had quite a roll at the break.

And I've met pilots who were scared to death of stalls etc. I never quite understood that - how can they be competent if they don't reinforce stall practice occasionally?

[Genghis the Engineer]

And I've met pilots who were scared to death of stalls etc. I never quite understood that - how can they be competent if they don't reinforce stall practice occasionally?

Some years ago, investigating the loss of an aircraft during its annual air test, I went and interviewed the owner (the pilot, who thankfully survived - just - had been an independent check pilot).

Me: "Can you tell me what the aeroplane normally stalled like"
Owner: "Stall? I never stalled, I'm not stupid."

G

[barit1]

R&N has two threads about a Jet Airways check capt. who pulled a circuit breaker disabling the R/A. The PF landed "with difficulty" per the press release.

Leaving aside the issue of pulling CB's on a revenue flight (although I am reminded of Ernest Gann's trial by fire as a new DC-2 FO) - What is this world coming to?

[opherben]

Excellent post JF!
I'd add that certification of regimes such as stall, inherently a departure from controlled flight, is a detailed subject, and not suitable for forum elaboration.
I was about to fly the prototype F-14A with improved ARI the day on which the chief USN test pilot spun it to the Chesapeake Bay. Even the most experienced might find this regime too much for them to handle.

[Double Zero]

J.F,

I was once ' along for the ride ' - as you know I''m SLF or similar - in a light Piper twin we're both familiar with.

The pilot was an irregular, ex-Lightning pilot about to go to Saudi on export Hawks, kicking his heels and got the job of checking this aircraft's stall warning system, which had been U/S, now apparently rectified.

He was already the only pilot who has truly frightened me, flying the same aircraft so low that I could see the bolt-heads on a pig-sty, then through rather than over ( at less than gable height ) the farm near the end of the runway.

At the end of that flight, the very distinguished ex-Hawker Test Pilot flying with us as an observer ( and I think the said pilot was out to impress, HUGE mistake ) got out and never said a word, but I think there was a large bubble above him saying " Prat ! "...

We got to just about 2,000' directly over the airfield, when he throttled right back and pulled the nose up - unfortunately I don't remember watching the instruments apart from altimeter, and of course unlike a fighter there was no obvious A of A display, as I recall.

The aircraft was kept wings level, we ' mushed ' only for a very brief moment before a fairly violent ( to me anyway ) ' hammerhead ' ? stall, with steep nose down and a lot of throttle applied to combine to get us back up.

The stall warning hooter certainly went off at what I'd think was the right time, before mush & nose-down, but was this a correct test at that altitude ?

I'd tend towards the 'shudder to think' school of doing it on one engine, but you seemed to quite like that aircraft.

I realise this was very different from testing a prototype, and only checking the warning system, but to a pleb like me we seemed a bit low for such antics, & the pilot wasn't really used to that aircraft, especially if the thing hadn't stalled benignly, even then somewhat eagerly seeking Mother Earth ?!

DZ

[Dudley Henriques]

I was about to fly the prototype F-14A with improved ARI the day on which the chief USN test pilot spun it to the Chesapeake Bay. Even the most experienced might find this regime too much for them to handle.

Small world! If you're talking about the #619 test bed Turkey that DD Smith and Pete Angilina spun into the bay, DD and I flew that bird the week before they lost it at Strike.
Dudley Henriques

[Pugilistic Animus]

wonder what 'Spin Master Gallagher' has to say on it;)

[opherben]

Hia Dudley,
that's it! I graduated USNTPS class 69. DD's eyes were sort of reddish for a fortnight from the herendous initial longitudinal g force...
About stalls and spins, a good friend I haven't seen in ages is Jack Krings. He piloted the first YF-18 flight and did some work on F-4 spin, interesting on an aircraft which is not supposed to recover:eek:.

Good luck to Boeing on today's B787 inaugural flight!
Happy holidays everybody!

[Dudley Henriques]

Small world indeed, and "Hi" back at you :-)

I was down there twice actually. The first time as a guest of TPS to fly the T38. The second time as a guest of Admiral Brown and Strike to try on the F14.
The guys I remember would be Tom Flannery, Jack Battenberg, Nial, and of course Tex Birdwell and Johnson who releived him during the time I was there.
Paul Nafzinger worked with me on the T38 flights.
I remember well how DD looked after the punch. I still have a picture of his face around here somewhere. God what a mess he was. He was minus 7 erect and couldn't reach the curtain. He finally got hold of the lower handle to get out. Pete was right on the spin axis and had no comparable problem.
DD and Jo moved out to California near Mirimar. Last word I had was that he was a banker of all things :-))
I hope they survived all the banking mess and are still doing ok.
You mentioned the YF17 prototype. I never met Jack, but I narrated the demo for Northrop when Hank and Bob Elder brought the bird down to Pax for the air show.
That's another great DD Smith story. He was doing the demo in the Tomcat and I was narrating the demo for Strike. Admiral Holloway was standing right next to me as I did my thing on the podium. DD made a low pass blindsiding the Marine Corps band who were standing right in front of the podium. He went to zone 5 right over their heads. The entire band went down as one man not knowing what the hell was happening :-)
It was a great moment for the Navy with Holloway laughing at the whole thing.
I believe there were several rounds bought for the Marines later on over at the Belvedere to amend as the rest of us decided whether or not we could get away with stealing the bull off the roof of the motel :-)))))))))
Great times; great people!!!!!!!!!!!!!!

Dudley

[barit1]

Perchance one of you know Lew Kosich - he later went to UAL on the 777.

[Dudley Henriques]

Perchance one of you know Lew Kosich - he later went to UAL on the 777.

I didn't, but I was only at Pax as a guest pilot for a short time.
DH