Question Re C. A. R. S. And Approach-To-Stall Training


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Researching the cross-references in the CARS is a huge task and before I launch on that journey I am wondering if anyone can help with interpreting the following CARS reference with regard to PPCs and Approach-to-Stall training - specifically, C3, below.

CARS Standard 724 Schedule I, PPCs ( http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part7-standards-a724a01-414.htm )

Canadian Aviation Regulations (CARs) 2012-1

Standard 724 SCHEDULE I - Pilot Proficiency Check (PPC) - Synthetic Flight Training Device

Content last revised : 2005/06/01

. . . .

Manoeuvres

(i) At least one steep turn in each direction with a bank angle of 45° and a change in heading of at least 180° but not more than 360°;

(ii) Approaches to stalls

For the purpose of this manoeuvre the required approach to a stall is reached when there is a perceptible buffet or other response to the initial stall entry.

The following approaches to the stall are required during initial and upgrade PPC's:

(A) one in the take-off configuration, except where a zero-flap take-off configuration is normally used in that model and type of aeroplane;

( B ) one in a clean configuration; and

(C ) one in a landing configuration.

One of the approaches to stall shall be performed while in a turn with a bank angle of between 15° and 30°.

(iii) Steep turns and approach to stalls are not required when the PPC is conducted using either a LOFT scenario, a scripted PPC or a fly-by wire aeroplane; and
(amended 2000/12/01; no previous version)

(A) for an initial PPC on aeroplane type, steep turns and approach to stalls have been satisfactorily demonstrated during initial training;

( B ) for a semi-annual or an annual PPC:

(I) steep turns and approach to stalls that are required in the applicable annual training syllabus have been satisfactorily demonstrated during this training; or

(II) steep turns and approach to stalls are not required in the applicable annual training syllabus.

It seems to me that in fly-by-wire aeroplanes, the CARS do not require approaches to the stall training except in "initial and upgrade PPCs".

Does the word "aeroplane" in C3 above mean an actual airplane or is it just referring to airplane type (fbw) but still comes under Standard 724 "Synthetic Flight Training Device"?

Put another way, does this mean that the approach to stall training is not required in FBW aircraft except in initial and upgrade PPCs if the aircraft to which the pilot is transitioning is a FBW aircraft? If so, I presume that this would include the Boeing 777 as well as Airbus fbw types.

Does the description "synthetic flight training device" mean only a full flight simulator? Certification of "Synthetic Flight Training Device" is addressed in CARS 606.03 ( http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part6-606-2439.htm ) but I haven't followed all the references to determine if the term means a Level D sim or...?

Thanks!

Don

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Hi Don

Partial answer I think. The term "aeroplane" is used ( ICAO and therefore TC) to differentiate 'normal' aircraft (Boeing, Airbus, Cessna etc.) from the rest (helicopters, balloons, gliders etc.) The term "aircraft" is all encompassing, whereas the "aeroplane" invokes a winged, powered (I think) vehicle subset from the others.

WRT the fbw annotation, that is the way I read it, but I'm not sure about the 777. My understanding of the fbw logic in the 777 is that the aircraft will fight you but ultimately it will let you stall the aircraft without any special efforts whereas the Airbus will not let you do these bad things without going down several levels of law.

I hope that helps, at least a bit.

Bob Perkins

Edited by Robert Perkins
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In reverse order!....Malcolm thank you - that confirms my interpretation of both terms; CD thank you as well - I'll dive into 705 - I believe the same thing applies and will look when back from the gym; Bob thank you also. My interpretation in re the B777 is that it is a fbw aeroplane just like the Airbus A320/A330/A340/A380 series. That means the airplane is controlled by C* laws and not cables/pulleys/hydraulics between the flight controls and the cockpit controls.

The B777 does have some protections though not nearly what the Airbus does but in my interpretation that isn't germain to the meaning of "fbw" in the CARS. "FBW" means just that, (C* laws...long established) and has nothing to do with any "protections" which are merely add-on's. As far as I know, no current jet fighters have "protections", at least in the way Airbus, the B787 and to a lesser extent, the 777 do.

Put another way, it is not "fbw" that "protects" one, it is the software downstream of whatever controls are installed. "Protections" in a conventional design would be things like stick-pushers, yaw-dampers and "Mach-tuck preventers"...(the DC8 had one - forgotten what it's called, other than "the snake").

So in that interpretation, all fbw including the B777 are included in the rule.

So I'm still at a bit of a loss...are approaches-to-the-stall required by the CARS when the simulator is of the aeroplane type that has FBW controls?

Thanks guys...

ed. From http://www.tc.gc.ca/eng/civilaviation/publications/tp14727-flight-508.htm :

"For 704 and 705 PPC's conducted in a flight training device, ACPs need not evaluate approach to stalls when the PPC follows either a LOFT scenario, a scripted PPC or is for a fly-by wire aeroplane; and. . ."

I wonder if that clears it up? There's nothing special about fbw. They'll stall the airplane just as easily as cables and pulleys will. AF447 proved that beyond a doubt.

So if this is the basis for the rule (not requiring stall training for fbw aeroplanes), I think the CARS mistake the concept of "fly-by-wire" for the concept of "protections". I think the two aren't related.

Don

Edited by Don Hudson
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I have always looked at it like this.

The airbus software will do whatever is necessary to protect the aircraft (within limits) in spite of the pilot

Boeing will allow the pilot to protect the passengers and crew in spite of the aircraft.

Meaning Boeing will allow you to exceed limits in extreme cases when necessary where Airbus will protect the airframe within the limits set in the software.

Having seen that structural integrity of the aircraft can be maintained well beyond the original limits set out by the design engineers, I prefer the Boeing philosophy

Yes this is oversimplified .

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Thanks boestar.

A few of my landings tested the airframe integrity of the B727 so I can't disagree with your preferences! Mind you, the unlocking bogies on the A330 & A340 sometimes felt as though we'd been shot down from a great height as well... :whistling:

This is more about whether the approach to the stall and stall recovery are not being trained and checked when industry experience has over a dozen stall accidents on Boeing, Douglas, Airbus and ATR aircraft*. I'm not a structural or aeronautical engineer so I can't make a judgement on airframes but industry experience seems pretty uniform no matter which manufacturer is examined. IIRC, the last accidents in which the source was primarily structural were the Lockheed Electra and before that the Comet.

* - out of the following accidents not all were fatal accidents and not all were amenable to recovery due to ground proximity but all were unintentional stall entries except the Airborne Express DC8.

-AF447, A330, mid-Atlantic Ocean, stalled due incorrect crew response to UAS, June, 2009
-Turkish Airlines, B737, stalled on approach, Amsterdam, The Netherlands, February, 2009
-Colgan, Q400, stalled during approach, Buffalo, New York, February, 2009
-Fedex, ATR42, stalled on approach, non-fatal, Lubbock, Texas, January, 2009
-Air New Zealand/XL Airways, A320, stalled on test flight, Perpignan, France, November, 2008
-Spanair, MD83, stalled on takeoff due zero-slats/flaps t/o, Madrid, Spain, August, 2008
-One-Two-Go, MD82, stalled due go-around thrust not applied, Phuket, Thailand, September, 2007
-Thomson, B737-3Q8, stall and recovery on approach, Bournemouth, Hampshire, September, 2007
-West Caribbean Airways, MD82, stalled during engine failure/thunderstorm proximity, Venezuela, August, 2005
-MK Airlines, B747, fail to get airborne, Halifax, NS, October, 2004
-Airborne Express, DC8, stall test, Virginia, USA, December, 1996
-Airbus, A330, stalled on test flight, Toulouse, France, June, 1994
-China Airlines, A300, stalled on accidental go-around & loss of control, Nagoya, Japan, April, 1994
-China Airlines, B747, stalled after engine failure, a/p remained engaged, San Francisco, USA, February, 1985
-Air Florida, B737, stalled due wing contamination, Washington DC, January, 1982
-Northwest Orient, B727, stall due UAS event (pitot heat off), Stony Point, New York, December, 1974

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CD;

Apologies for the tardy reply!

My thanks for providing these three valuable links. I'd have been a long time finding them - greatly appreciated!

I have read through them to find something that might answer my question. Policy Letter #172 and Advisory Circular #0247 are similar. All three documents are well-written, very informative and provide solid guidance for teaching/checking the approach-to-the-stall, the stall, and various aircraft systems that prevent the stall "such as stick pushers".

However it is "when" and not "how" that is being set aside in these three documents and the document describing what is to be checked in PPCs for 704 & 705 operators. I haven't seen anything that requires the demonstration and checking of the approach-to-stall or stall on FBW aircraft once the initial PPC or the upgrade PPC has been accomplished.

This means that while TC's checking of a candidate's understanding and performance for this manoeuvre is mandated as described, it is not mandated as a recurrent item and so the approach-to-the-stall will only be checked once, possibly twice in a pilot's time on an aircraft.

I see on the CBAAC-0247 issued by Director Gaudreau that the date of issue is March, 2011, just before the flight data recorders from AF447 were found and read.

Granted some operators may be (and have been) taking this issue on on their own initiative but so far I haven't read any requirement (or any formal authority in the CARS) for TC to check "approach to the stall" in a FBW airplane after the initial or upgrade PPC.

I'm raising this within the context of the broader issues of competence in manual aircraft handling, which includes the correct handling of Airbus (and now Boeing) aircraft when sophisticated software limits which are intended to prevent even the approach to the stall are not functioning, (as in Alternate 2 and Direct Laws on the Airbus A320/A330 series aircraft).

I could be missing something here and if so I'm glad to have it pointed out.

Thanks again, CD.

Don

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In December, on my last training session, both of us had to recover from a deep stall at high altitude, not at just stick shaker. It was done, not by any decree from TC, but to enlighten canditates. Nice.

If it's not done at your shop, I recommend that when the instructor ask if you would like to practice any maneuver, ask for a high altitude stall at 38000ft.

Cheers

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Boney;

Yes, nice, and good to hear of it.

BTW out of interest, how did the recovery go? Can you describe it? I've seen analysis of the AF447 flight data for recovery at varying altitudes, (FL380, and as low as FL60). Recovery at higher altitudes took longer and lost more altitude. Recovery at FL60 barely cleared the water...academically-speaking!!

Don

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The exercise was to demonstrate 2 events.

The first was an everyday encounter with mountain wave. The event is the sudden increase in speed of 10 kts in the red. Recover. Initial reaction, thrust levers to idle, disconnect autopilot and slow down. Of course the clacker is on. The instructor stops you from bringing up the thrust to early for the exercise. When engines are stable at flight idle, how long does it take for spoolup? That's where it gets interesting. As the speed exits the high regime you set max thrust and wait the 30 to 50 seconds. You are required to maintain fl380 as long as possible. Now you get the stick shaker and your engines are coming up. Recover.

The second part is to not bring up the engines till you are fully stalled. Well in the red by 60 kts, sticker shaker on and v/s is showing 2-3000 fpm, hearing the wing reverbarating and all the while the airplane vibrating. Recover. Fire wall the levers and nose down, start with 15 degrees, increase as necessary.

We lost about 8-10000 ft for recovery. Nice.

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A very interesting thread. That sounds like excellent training, Boney.

From the PPC Schedule: Steep turns and approach to stalls are not required when the PPC is conducted using either a LOFT scenario, a scripted PPC or a fly-by wire aeroplane;

It's the "scripted PPC" reference that has the greatest effect IMHO. The vast majority of PPCs are scripted and I find that realism suffers if you have to force steep turns, a takeoff stall, a cruise stall and a landing stall into the middle of a PPC. Having said that, I'm a big fan of AC 0247. It wasn't initially very well received by the trainers. As an ACP, I found I could ensure that it got included in training by saying that I would be checking those items on the PPC. Since then, I've seen broader acceptance of AC 0247 so I'm happy not to check stall recoveries on the PPC.

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Boney;

The altitude loss is in the neighbourhood of sim trials done after AF 447; some losses were as high as 20,000ft. It takes just under a minute to get the AoA from 35+deg (the AoA at the apogee in the AF 447 accident) to less than stall AoA while pointed down.

Also, pointing Nose-Down to 15deg is not within ordinary transport pilot experience so actually doing it during a PPC is good exposure to what may actually be required. The FCOM talks about "5-deg below the horizon" if I recall it correctly, which may work well lower down but not well at cruise flight levels.

Aerodynamics of high-speed, high-altitude, swept-wing flight were never taught (and aren't in Davies!), and I had not understood until AF 447 that transport aircraft cruising at M0.80+ are always within about a degree-and-a-half of the stall AoA.

Canadairguy;

Re, 'Since then, I've seen broader acceptance of AC 0247 so I'm happy not to check stall recoveries on the PPC"

Sorry, trying to interpret this...does this mean you're okay with checking the approach-to-stall just once and not requiring it again in PPC's?

Don

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Next time, I'm going to request that we continue the stall till airspeed is 60kts or less. That is what those poor buggers had to face. At that low speed one may need 20,000+ ft to recover. It does open one's eyes as to recovery from high altitudes vs low.

A silly question...The stick shaker was on the whole time with a CC. It certainely vibrates quite noticably when you hold the CC. Do SS also have this vibrating feature?

Thanks and cheers.

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Sorry, trying to interpret this...does this mean you're okay with checking the approach-to-stall just once and not requiring it again in PPC's?

Not exactly, Don. If I'm convinced that approach-to-stall has been done in training, I won't require it to be done again in a (scripted) PPC. In my experience, training is distinct from a PPC, it's done by a different person and it's done immediately following the training. Is your experience different?

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Re, "Do SS also have this vibrating feature?"

No, they don't. However, the audio warning, "stall, stall" is repeated until a) the airplane is no longer stalled or b ), the airspeed is below 60kts in which case there is "NCD", no computed data for the stall warning system to base information on.

canadairguy;

Thanks - re 'done in training', that's an important distinction I think and I understand your comment now. My experience (retired in Oct, 2007 off the A330) was not in accord with AC 0247 in terms of the depth of the discussion regarding the stall, but I note that the document was modified in March of 2011. That said, I never saw a UAS event in the sim and we never reviewed/discussed the scenario even though the A330 had had numerous such events including dual ADR failures due pitot icing, after 1996. Before AF 447 neither this scenario nor 'stalling in transport category aircraft' were "on the radar", so to speak. Through discussions I believe they are now and I'm gratified to understand through your response, how it is being observed. My thanks once again.

Don

Edited by Don Hudson
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I think Roger Ramjet , the infallable airline pilot has been brainwashed into being extremely reluctant to bust their altitude when presented with a situation where the aircraft needs to be righted by either adding power or getting the nose down to decrease the angle of attack.

The problem with the SS as I read, is that there is no feedback as far as back pressure goes.

In any stall practice I have ever done it is always stressed to reduce "back-pressure" (hard to do with no feedback with a SS), but by reducing the back pressure, one is lowering the nose, thus decreasing the AOA. Once established that the aircraft is indeed descending, with the nose slightly below the horizon, apply full power and gently pull out of the ensuing dive when one has a significant airspeed...(without precipitating another stall).

The hell with how much altitude one loses as long it is not water or terra firma at the bottom of the attempted pull-up.

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Kip;

Yes. I have learned this much in the generously-offered comments here, and in discussions over the past couple of years, especially concerning the AF 447 accident and its crew. The industry is quietly better for these kinds of discussions which have taken place.

Decades ago, minimal altitude loss was a primary PPC parameter - the industry has progressed far beyond that today. Rich states it very well; - unloading the wing is primary and maintaining a pitch attitude which ensures that a flying AoA is achieved, assures the primary parameter.

One thing I have learned and continue to learn over the years about how aviation is conducted in Canada is, issues don't necessarily need to be written out to be already on peoples' minds and already in motion. Perhaps at times the documentation catches up with the way people are already doing things. I sense there are other aspects of Canadian life that are similar.

Don

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We did the high altitude stall as well. At 410, no auto, thrust at idle, let her slow and maintain alt. Stick shaker banging away and when unable to maintain alt, pull the yolk into your gut and wait a few seconds more. The biggest surprise for me was that we were capable of maintaining alt down to an indicated airspeed of about 160 knots!! The recovery was fairly benign, lost about 5000 feet. B-737NG.

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Of course everyone is tempering their flight sim experiences with the fact that the aerodynamic model for high altitude stalls has not been derived from actual flight test data, but a best guess by the algrorithms in the software.

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Like JL says, I know that there are simulator modules that are not necessarily accurate depictions because they are based on interpolations/extrapolations or are 'reverse engineered' (for example simulators for 'common types') to make it a simulation. My experience is such that those modules are, among other things, commonly in the high altitude and unusual attitude envelopes.

Depending on the simulator manufacturer, they may or may not have data from the aircraft manufacturer's certification testing.

The takeaway- just because you experienced it in the sim does not mean it would be identical in the airplane. And in some cases that may actually be for the better. Take United 232 for example. They claimed that all (most?) of the crews that tried to simulate what the 232 crew did never got anywhere near a survivable landing. Respectfully, it doesn't mean those 4 pilots were better than everyone else- it just says to me that the simulation was not an accurate depiction of the conditions that Haynes and crew were in that day.

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Canoehead;

Good post.

Electrons and pixels cannot replicate but can only mimic mass, inertia, 'g' and the physical forces acting on a real airframe.

The last airborne type-rating I experienced was on the L1011. We went to Trenton for four hours of circuits. Our training up to that point was in the sim - if I recall, it was considered a Level D simulator, (six axes of motion, full visual).

We practiced engine failures in it and in the airplane. I was immediately struck by the "solidity" of the aircraft's response...there was no doubt about the control inputs and the response of the airframe.

In contrast to the aircraft, the sim was very much a 'soft', virtual experience. It was sufficient to train in for operating the airplane (providing one was already experienced and it was just a type-rating or upgrade!), but most certainly it was not the airplane.

I've talked to others on the "veridicality", (that's the word the guy used....I had to look it up!), of the stall regime in simulators. While there is very little supportive data because no manufacturer's take their airplanes in to full stalls anymore, the opinions that I've heard are that the algorithms are 'pretty good' and reasonably repeat behaviour of the airframe in those circumstances.

I'd leave up to the trained aeronautical engineers who were also test pilots, the certification and the regulatory people to determine to what degree that capability can relied upon to "teach", (ie, 'let's do the AF 447 scenario, etc), but in my own experience in the sim, the stall and the recovery process was reasonable to an airline pilot. There's nothing in the FCOM that states how to recover from a full stall. No FCOM is going to state that "the airplane requires a 15deg ND attitude held until the wing is flying again but be careful on the pull-through"!, so it's sort of like saying it made sense with what a pilot would do in the airplane because it resonated with past experience and the recovery procedure, as Boney has described, worked.

But, dollars-to-donuts, if at the apogee the AF447 crew had held full ND stick, the airplane would have recovered, even with full-up THS*.

Don

*The THS ran to full NU during the initial zoom-climb, but in the sim runs back to normal position if the stick is held ND long enough. The sim stall recovery in these circumstances usually took about 40 seconds and 15,000ft.

Edited by Don Hudson
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mo32a:

The airframe is in fact brought to a full aerodynamic stall in flight testing and then recovered. The problem is the behaviour of the airframe AFTER the stall is fully developed. We like to keep the test aircraft in one piece and the pilots alive so exploring the effects after the stall are the realm of theoretical physics and mathmatics to figure it all out.

Up to the stall we have the data beyond that its all 1s and 0s

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