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-   -   TOM stall? (https://www.pprune.org/rumours-news/300235-tom-stall.html)

Tee Emm 18th Nov 2007 11:36

As a matter of topical interest we conducted a go-around at runway level in the 737 simulator today and made no correction to the pitch up that occured at GA thrust. The aircraft pitched up quickly and reached 45 degrees nose up and still going up and speed falling back through 90 knots when we "froze" the sim. This is a standard exercise to demonstrate to new crews the importance of containing the pitch up when hand flying and to monitor the pitch up rate if an auto-GA. A picture is worth a thousand words.

G-SPOTs Lost 18th Nov 2007 11:59

Don't shoot me too soon but in Tech Log right now we have the following thread:

1. Are visual approaches in airliners appropiate?

And on here:

2. TOM Stall (Alluding to an aircraft stalling due to nobody minding the shop) my italics

Anybody other than me seeing the pattern emerging?? Same routes, same "lowest common denominator SOP's" for all skill levels, reliance on automatics.

Anybody remember the "Children of the Magenta - American Airlines Video"
Who's flying the aircraft?

Airbubba 18th Nov 2007 12:51


It never fails to amaze me how ridiculously trusting people are of the results of using a TRAINING simulator to investigate the behaviour of an aircraft operated outside of the training envelope.
I agree. The sim may be a great tool for researching things like how a pilot will recognize and respond to an unusual attitude but using it to predict what the plane will actually do at unusual attitudes and airspeeds is a bit of a stretch. Still, sim results are often included in accident reports with little caveat.

puddle-jumper2 18th Nov 2007 15:21

Rainboe,

Your comments regarding reliance on Auto-throttle is all too true.:D

I spent 16 years on an 'old' tech jet and have recently converted to the high tech type. Having spent over 10 years in the left seat of the old girl with no Auto-throttle and visual approaches everywhere, I now find after just 6 months on the new jet I'm so used to letting the A/C do it that when I do take out the A/P and A/T I'm working very hard indeed.:(

I guess I'm going to have to bite the bullet and do more manual approaches.

runawayedge 19th Nov 2007 08:23

As a non pilot and merely an as observer, my understanding is that before an aeroplane ever takes to the skies that most of the predicted flight envelope calculations are proven by computers and simulators and post certification are used to demonstrate and practice unusual attitudes and situations. Was the Washington 737 accident not proven with substantial input from the simulator. So why having input all the parameters into the sim would it not be beneficial?

Shiny side down 19th Nov 2007 09:03

best analogy I can give a non-pilot is painting by numbers.

All the colours end up in the right place, but the picture isn't nearly the same as the original.

The actual response and feel of the sim is quite a bit different compared to the aircraft.
Real manoeuvers in the plane are easier (and dare I say it, more stable) than in the sim.

hetfield 19th Nov 2007 09:04

Correct Rainboe. We tried to do the DHL Baghdad thing in the SIM (complete loss of HYD, A300).

No way Jose`.

Kit d'Rection KG 19th Nov 2007 10:15

This is why engineering simulators exist and are used to analyse safety events; they replicate the aircraft much more faithfully, at massively greater cost.

yeoman 19th Nov 2007 13:13

I understand the sim exercises were looking at how the situation developed and not in the handling / performance of the aircraft.
Use of automation is all about using an appropriate level of automation to suit the situation. This can vary from full manual to Cat 3B autoland. Gone are the days when you heard "I've got a Base Check next week so I'm going to do a bit of manual flying". It had got to the stage where we were using the aircraft to practice for the sim, ie, often using an inappropriate level of automation. Has skill fade resulted? Among 200 pilots you will get 400 answers on that one!

Oh, and one of the guys is a mate so when we're all done we could wait for the report and probably even learn something. Well most of us, the experts out there have it all taped right?

ABUKABOY 19th Nov 2007 13:47

We too tried, as did Hetfield, the Baghdad scenario. We initially got control of the basic aircraft parameters, but very soon lost them; a shallow dive, speed building, and the need to apply power to raise the nose, no way possible in the sim, and three of us had a go that day and failed, as the terrifying fugoids developed.
Our sim was one of the better ones regarding similarity to real-time handling, and I guess we will never know whether it was down to us or the sim on the day.
.
Major respect to that Baghdad crew for achieving the theoretically impossible.

Rainboe 19th Nov 2007 16:43

...for another year. Bye bye!- hear from you next November!

45989 19th Nov 2007 16:53

Dont knock him so quickly. a very valid point i think.

Airbubba 19th Nov 2007 17:50


Was the Washington 737 accident not proven with substantial input from the simulator.
Do you mean the US Air 427 crash out of PIT?


The Idaho DC10 accident was replicated in the simulator
I think you mean the Iowa crash, UAL 232 at SUX - Sioux City (http://www.flysux.com/).

Regardless of the geography, those crashes are a couple of the first that come to my mind on this topic. Sims were used to test theories about handling with catastrophic system failures.


Gone are the days when you heard "I've got a Base Check next week so I'm going to do a bit of manual flying". It had got to the stage where we were using the aircraft to practice for the sim, ie, often using an inappropriate level of automation.
Those days aren't gone everywhere. I do have mixed feelings when the other pilot hand flies to FL330. It's great that they are maintaining stick and rudder skills but it puts a higher workload on the monitoring pilot and narrows situational awareness. Of course, if we are flying a European SID with noise abatement and a low transition altitude, I'm a little firmer about getting the autopilot on so we can run the store. Also, stick time helps some when you get to the sim, but most of us spend the first hour relearning how to fly the box.

Rainboe 19th Nov 2007 18:43

Sorry- you are correct. Knew it was I-something. Idaho is where the lovely baked potatoes come from. The Sioux City accident it was. Wonderful interview with the crew shown in Recurrent training. Respec'!

Right Way Up 19th Nov 2007 21:18

FOK,
Whether in the sim the event is controllable or not is irrelevant, what is more important is whether it is representative of the aircraft. As most posters have suggested the simulator will not have the data to replicate this scenario. You may as well have a test run on MS Flightsim.

Right Way Up 20th Nov 2007 09:44


Well the CAA seem to think it is?!

... and they certify the sims
That would be the same CAA who allegedly stopped the old VS classic sim from being certified because of a supposed "errant" instrument flag, until they were told that the aircraft did the same.

Back to the original point, the sim will not represent the aircraft in such extreme attitudes, because the sim will not have the data available to it.

Mad (Flt) Scientist 20th Nov 2007 10:49


Well the CAA seem to think it is?!
... and they certify the sims
A training simulator is qualified by comparison of its behaviour against a defined range of manoeuvres which are intended to validate that it is sufficiently representative to undertake the training role for which it is intended.

It is not validated for use for manoeuvres outside that envelope, and use of a training device for engineering purposes - whether for investigations such as that suggested, or for certification purposes (such as, say, windshear escape guidance certification) is subject to substantial additional validation testing, often of the same magnitude again as that used for the training validation. All of the certification agencies are well aware of the technical limitations of a basic flight training simulator; they are the ones requiring the additional validation (though I would not propose its use without that validation, even if they did not).

BOAC 20th Nov 2007 12:50

.......which is why you can fly inverted under Sydney Harbour bridge in a 737-400 sim:). Go on - ask me how I know...................

Right Way Up 20th Nov 2007 14:50

BOAC,
Come on now stop exaggerating. Everyone knows the bridge being in Oz is upside down, so in fact you were the right way up! ;)

BOAC 20th Nov 2007 14:56

Well, jigger my kangaroo, Bruce - you are right!:)


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