Exactly!

Why havent they carried out these tests? Surely if the deep stall tests could be carried out during test. If the situation was unrecoverable, then a recovery parachute in the tail could be deployed. That should at least get the nose pointing down. I thought test pilots were of the "right stuff". Seems i maybe wrong. Are crews now, part of the test flight program? Has Health and Safety hamstrung flight testing also?

Yes i know we shouldnt get into these situations but we do, humans being humans.

Dan, most manufacturers explore both the stall boundaries and after effects.
Depending on aircraft type, stall characteristics can vary widely. Small differences in build quality or maintenance, structural flexing, weight variation, control rigging, ... all add variability to many uncalculable aerodynamics effects.

See the NASA report relating to 737 stalling, including high altitude. There is reference to a simple stall model suitable for the task, but first define the task; awareness, recognition, avoidance, or recovery. Then provide the funding according to means and need, considering the ever present variability of the human. You could train everyone, but never be assured of the behaviour in operation.
And how many accidents have their been from unrecovered stall encounters in situations where recovery was feasible, i.e. not very low altitude, impaired controls, etc.

“All airline pilots agreed or strongly agreed that they were surprised by the surprise stall scenario. In that scenario, less than one quarter of the airline pilots strictly followed the proper stall recovery procedure on which they had been briefed. Less than half maintained a nose-down input until the stall warning stopped.
It may not matter what stall model you use if pilots are going to react inappropriately; better to avoid the situation altogether.

https://www.faa.gov/pilots/training/...r_Training.pdf

This thread has gone from a simple discussion to the absurd! Deep stall discussion is similar to how low can you go. Simulators are toys programed to behave and react in certain ways that are predetermined. Stall should be recovered from with the least amount of altitude lost even if the buffet continues for several seconds longer. A buffet can occur at cruise when operating at almost maximum altitude and a bank of something around 20 degrees. Apply some thrust and minimum roll and the buffet is gone. I remember the days of training in light aircraft. Idle thrust hold altitude and wait of the buffet/horn. Keep the nose up and wings level in falls through. Don't change a thing, the nose falls, speed rebuild followed by another stall, again and again.

The discussion about don't roll wings level is really more airframe specific. Some use a spoilers for roll, that brings about a whole new topic.

Keep it simple and you will not kill yourself.

Why?

Spoilers or no, if the region of the wing where the aileron is is stalled, an aileron input will stall it deeper and the plane will roll counter to the roll input.

If there's no need for a hurry to roll, better to wait longer rather than shorter to make sure the wing is completely unstalled.

Vessbot...agreed..I thought for good reason powering out of stalls had gone out of fashion, certainly on anything with underslung engines....

I certainly can’t speak for the 737 but FWIW after the well known high profile stalling/ incidents/accidents worldwide a few years back our Boeing big twin procedure was amended by Boeing to this:

(My emphasis added)

As currently taught (and as in the QRH and FCTM) the emphasis is on doing it very much sequentially i.e. you must get rid of the buffet before rolling or applying thrust.....

5 deg down, full power and waiting for 250 kcas...yes then i ll look for you at the center of the earth...ffs

Some really bad information here. 5 dog nose down might not break the stall. And waiting for x airspeed to pull?How hard are you going to pull? How heavy are you? How high are you? Or does any of that aerodynamics and physics stuff matter?

Simulators don’t have post stall AOA fidelity. That’s the change. A and B have agreed to a generic n/b post stall fidelity model.

You can’t compare current, or especially older, ‘stalls’ in a simulator and pretend they’re the real thing. They’re not.

I’m not sure how you can look at this video and write “apparently well trained” -

Attempting to answer Centaurs’s opening question logically;
Emergency manoeuvres - EGPWS Pull Up, Windshear - recommend speeds as low as ‘respecting the stall warning speed’, normally 1.1 stall speed.
However, this assumes that the aircraft has a stall warning system which corresponds with the general certification requirements - surprising if not. Furthermore, that the high level stalling characteristics are similarly warned, and that the stall margin (Mach effects) enable reasonably safe flight at this low speed - possibly not.

Given that altitude loss is not an issue at high altitude - no not even considering risk of collision etc, etc; focus on the primary safety issue. Then starting a gentle pull up after loss of stick shake, aiming to level / climb at a higher speed (min manoeuvring?) would appear to be safe. But further problems are the sensitivity of the speed display at altitude (flap speeds, etc, not available) and the use of Mach for reference. These similarly can be overcome by trading altitude for speed - turb speed, which might be required anyway for turbulence/ manoeuvre, i.e. addressing factors which could have contributed to the stall situation

Always test assumptions and logic - comments?

That is exactly what you should NOT do. That technique works fine during an approach to a stall, but will quite likely get you killed in an actual stall. 747 or C150

Can the commercial aircraft be tested like an aerobatic aeroplane? The design and purpose is to fly them within certain boundaries. If for whatever reason a line pilot ventures beyond that then the uncertainty of the outcome must be accepted. China airline 747 survived a barol roll but wasn't designed or can't be tested for that.

Super trio of Tube's by D Davis' days test flying. I thought I'd pop in for a moment, but two hours later I was still hanging on every word.

I'd owned his book since 1970, though seen my crew's later copies, however, I'd never heard him speak before. A bit of Winkle Brown in his delivery.

One thing in the later book was an impassioned plea to enable crews to be able to get hands on a real aircraft for occasional real flying. Probably gave bean-counters nightmares.

I was lucky, for years I was able to take the real aircraft into the stall, (Viscount) or push, (BAC 1-11) It's true to say that while I enjoyed that era, I was always rather perplexed by the lack of trainer's knowledge about pulling out of the (substantial) dive. I recall doing two or three in quick succession from 30,000 and getting a good view of the ocean before feeling any significant g. I had NO guidance on the recovery commencement. Great fun.

Of course, getting the load off the wings was done for me by the nitrogen ram. The Claxton made quite sure one was not nodding off.

If you want to hear what D P Davies had to say about stall testing and other aspects of certificating aircraft, go to this thread. These are the ones I think Loose rivets was referring to above.

https://www.pprune.org/tech-log/6029...-aircraft.html

A couple of DC-10's have been accidentally stalled with the result that various bits fell off due to the buffeting.

Report: Fedex DC10 near Raymond on Jun 14th 2008, aerodynamic stall while in holding

http://www.fss.aero/accident-reports...9-11-11-US.pdf

Vesspot. WHY? Because you might be near the ground and die.Stupid statement.

Check Airman.Because you might be near the ground and die! Again a stupid statement from you.

At high altitude its not important how much altitude you lose but hear the ground YOU MIGHT CRASH BURN DIE

[QUOTE=misd-agin;10055151]Some really bad information here. 5 dog nose down might not break the stall. And waiting for x airspeed to pull?How hard are you going to pull? How heavy are you? How high are you? Or does any of that aerodynamics and physics stuff matter?

Simulators don’t have post stall AOA fidelity. That’s the change. A and B have agreed to a generic n/b post stall fidelity model.

You can’t compare current, or especially older, ‘stalls’ in a simulator and pretend they’re the real thing. They’re not.

/QUOTE]

I’m not sure I understand what you are stating here.0

As of now (most) regulations only require datapacks with stall models up to onset of initial buffet or thereabouts.

On March 30, 2016, the FAA published changes to the 14 CFR Part 60 Qualification Performance Standards (QPS) that define updated general, subjective, and objective testing requirements for high angle of attack modeling and the qualification of full stall maneuvers on Level C and Level D FSTDs.

EASA published NPA 2017-13 addressing many changes including advance stall.

Some of the founding members of AUPTRA have conveniently merged UPRT with advanced stall to produce ridiculously high cost aero model add ons for FSTDs

Most changes will be in regulations from 2019?

Problem was AF447 was stalled and remained stalled until it hit the water. However the crew did not appear to have recognised they were in the stall. If they had known the situation, they would have attempted the correct recovery procedure. They didn't lower the nose sufficiently, IMHO. In the latter stages, was the situation recoverable? See FD recovered. I think they would have known if they were in a barrel roll, don't you??

The point is test flights are done to meet certification requirements. Also commercial aircraft cannot be built like combat aircraft. Then only thing they will carry is fuel. Besides since there are no ejection seats test pilots cannot risk there lives unnecessarily. It will be safer to ensure through better training that pilot will remain within the envelope. Stay clear of 447 otherwise there will be another 10000 replies.

Having just done an exercise in a 330 sim which was in some ways to replicate the AF447 incident, the amount of pitch down and altitude loss to unstall the wing, and then recover without inducing a secondary stall, was quite memorable. A few hands worth of forward trim helped.