Humbling sim experience
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Gravity waves can scare you if you are near maximum FL (high weight) and the margin between VMO and VAPROT is small. In the updraft side, it makes you reduce target mach in order to reduce thrust and avoid overspeed. In this situations I hate soft altitude in the ALT CRZ mode. It makes the airplane gain some feet and increase the speed when you want quick A/THR reaction.
Then, just after you manage to recover the speed, with quite a low thrust, the downdraft side comes and everything changes to worse, the soft mode will again be late to react, some feet are lost, speed bleeds off, but in this circumstances, high altitude and low margin, gaining knots is much more difficult than losing them, so you can see the speed trend going well below green dot and the airplane seems unable to avoid the speed from decaying. And that damned soft altitude... Oh, wait, but we already have max CLB, and still unable to recover speed... Well, if then the pilot panics and decides to descend to a lower level (which is the best course of action), for Christ sake, don't let him pull for an OP DES!!!!!
Then, just after you manage to recover the speed, with quite a low thrust, the downdraft side comes and everything changes to worse, the soft mode will again be late to react, some feet are lost, speed bleeds off, but in this circumstances, high altitude and low margin, gaining knots is much more difficult than losing them, so you can see the speed trend going well below green dot and the airplane seems unable to avoid the speed from decaying. And that damned soft altitude... Oh, wait, but we already have max CLB, and still unable to recover speed... Well, if then the pilot panics and decides to descend to a lower level (which is the best course of action), for Christ sake, don't let him pull for an OP DES!!!!!
Last edited by Microburst2002; 9th Jun 2012 at 15:06.
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hahaha
I meant Mountain Waves!
Anyway I think there is such things as gravity waves, which are basically mountain waves but with no mountains involved. But not sure.
Maybe I'll raise a thread about that, by the way...
I meant Mountain Waves!
Anyway I think there is such things as gravity waves, which are basically mountain waves but with no mountains involved. But not sure.
Maybe I'll raise a thread about that, by the way...
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@ BOAC,
The decision to climb was not unrealistic in this particular scenario, still some margin left. The winds changing was more due to the failure of the pitot static system an not the actual winds changing I've been told that the indications we saw were natural for the particular failure although in the real world it should have been a clue!!
@ at hazelnuts39
In hindsight, you are right, come to think of it, the speed didn't drop hence we kept slowly reducing the power.
Many mistakes made for sure, and when you contemplate it behind a pc screen the answers will be much different! However this took seconds to develop in the sim as it could be in the real world!!( think between level off and the stick shaker was about 5 seconds).
Great training, I learned something, reinforces the feeling that current training for civilian pilots is lacking. For the last 11 years I have done al sim sessions with average to above average grades and never got into any trouble. However, this was an ego killer and I learned a lot more than from the standard V1 cut, come around do an NPA on AP, GA and finish of with a hand flown SE ILS!!
Greetings
The decision to climb was not unrealistic in this particular scenario, still some margin left. The winds changing was more due to the failure of the pitot static system an not the actual winds changing I've been told that the indications we saw were natural for the particular failure although in the real world it should have been a clue!!
@ at hazelnuts39
In hindsight, you are right, come to think of it, the speed didn't drop hence we kept slowly reducing the power.
Many mistakes made for sure, and when you contemplate it behind a pc screen the answers will be much different! However this took seconds to develop in the sim as it could be in the real world!!( think between level off and the stick shaker was about 5 seconds).
Great training, I learned something, reinforces the feeling that current training for civilian pilots is lacking. For the last 11 years I have done al sim sessions with average to above average grades and never got into any trouble. However, this was an ego killer and I learned a lot more than from the standard V1 cut, come around do an NPA on AP, GA and finish of with a hand flown SE ILS!!
Greetings
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Microburst, there are indeed waves not associated with mountains. We sometime get them in East Anglia, UK, not noted for its sticking up bits. In my experience, and from what I have read, they do not generate such strong up and down velocity vectors as mountain waves, but for all I know there may be exceptions to that. Wave has also been seen on satellite photographs over the sea, far from any mountains – though with favourable conditions, mountains can generate waves a long way downwind as well as close to the triggering source.
One mechanism for wave without mountains AIUI is wind shear. Think lower high density fluid, with higher low density fluid having relative motion to it – such as sea/air interface. It seems that can happen higher in the atmosphere too, with adjacent layers.
(Glider pilot, not met man, and not ATPL)
One mechanism for wave without mountains AIUI is wind shear. Think lower high density fluid, with higher low density fluid having relative motion to it – such as sea/air interface. It seems that can happen higher in the atmosphere too, with adjacent layers.
(Glider pilot, not met man, and not ATPL)
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Good form,
My first sim check, 737-8, a 30 kt crosswind, temp -20C, snowing, with an iced runway...at night, in Deadhorse, AK....
BTW...full motion ...
Buzz Nelson was running the sim...
My first sim check, 737-8, a 30 kt crosswind, temp -20C, snowing, with an iced runway...at night, in Deadhorse, AK....
BTW...full motion ...
Buzz Nelson was running the sim...
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Hopefully we can stop the flow of low time cruise type pilots getting into the airlines, then monitoring autopilots and becoming captains with no actual flying experience hand flown. It probably isn't going to be allowed to happen because of the cost by the bean counters. It wasn't like that 30 years ago, you then had to know how to fly.
Microburst,
It is: power+ attitude= performance
It is: power+ attitude= performance
Also remember the same power+attitude gives vastly different performance depending on whether you are pre or post stall. AF447 was 16deg NU with full thrust- and descending very rapidly!!
Last edited by Wizofoz; 10th Jun 2012 at 05:04.
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Excuse me? No competent pilot in an airliner would expect performance at FL350 heavy at a 16 degree deck angle. No ONE. We can't let these inexperienced guys be together when the experienced guy has to take his break. Get one of the old 65+ year old guys that can handle it be the second pilot as CRUISE PILOT. They would know what to do. Trust me.
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Damn, I have to check more carefully what I quote!
Anyway I know you know what I meant, right?
Chrisn
Thanks a lot for that. I always wandered what the hell could make mountain waves without mountains. As for the latter, I find them very often in the same area and season, sometimes very intense.
Anyway I know you know what I meant, right?
Chrisn
Thanks a lot for that. I always wandered what the hell could make mountain waves without mountains. As for the latter, I find them very often in the same area and season, sometimes very intense.
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A bit more on mountain wave. In some circumstances, a localised area can have wave that has a vertical component the same as the wind speed. Unlikely though this might seem (need a diagram here – can’t find one to post), successively higher layers can pile up on each other, with a shorter local wavelength and more bending of the streamlines from horizontal to a steeper angle, until at a certain point they go vertical. In the lee of a Scottish Mountain, Morven (Aberdeenshire) on a day with about 10 knot wind, we found local lift of almost 10 knots for a while. Mountain waves are not always the classic sine wave shape.
This might be one explanation why even airliners experience up or down drafts which seem disproportionate to the general wind speed. As far as I know, however, this extreme is only found where the mountain shapes are right for it and at the same time the airmass characteristics (wind change with height, stable layer over unstable, etc.) lend themselves to this phenomenon.
I don’t know enough met to say if it could happen elsewhere than particular spots. I certainly don’t know what happens near jet streams.
It may be that the professionals don’t yet know that much, either. A lot of early work on wave came from gliding exploration of it, before the soundings and analysis/theories followed. For obvious reasons, there is not much gliding exploration of wave over the sea.
Chris N
This might be one explanation why even airliners experience up or down drafts which seem disproportionate to the general wind speed. As far as I know, however, this extreme is only found where the mountain shapes are right for it and at the same time the airmass characteristics (wind change with height, stable layer over unstable, etc.) lend themselves to this phenomenon.
I don’t know enough met to say if it could happen elsewhere than particular spots. I certainly don’t know what happens near jet streams.
It may be that the professionals don’t yet know that much, either. A lot of early work on wave came from gliding exploration of it, before the soundings and analysis/theories followed. For obvious reasons, there is not much gliding exploration of wave over the sea.
Chris N
Excuse me? No competent pilot in an airliner would expect performance at FL350 heavy at a 16 degree deck angle. No ONE. We can't let these inexperienced guys be together when the experienced guy has to take his break. Get one of the old 65+ year old guys that can handle it be the second pilot as CRUISE PILOT. They would know what to do. Trust me.
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Originally Posted by flyburg
]The decision to climb was not unrealistic in this particular scenario,
CBs = turbulence= need extra margins, not less.
Flying at 35.000 with an heavy airplane you climb to 37.000 which is just*
Possible with the weight. {I read very little manoeuvre margin?) Reason for the climb, you are flying just below the clouds in an area of embedded TS and it is bumpy.
Starting the climb(with just a small margin between upper and lower red band (I read with a small manoeuvre margin which you then throw away) but still.....
Possible with the weight. {I read very little manoeuvre margin?) Reason for the climb, you are flying just below the clouds in an area of embedded TS and it is bumpy.
Starting the climb(with just a small margin between upper and lower red band (I read with a small manoeuvre margin which you then throw away) but still.....
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The erroneous and exaggerated wind read out is to be expected with airspeed unreliable on the Boeing that I fly (I imagine the B744 is similar). A corrupt pitot static input causes the related ADIRU to produce all sorts of nonsense. IAS, TAS, Mach, W/V, stickshaker, overspeed, GPWS windsheer warnings, even the Altimeter can all be rendered unreliable. It is a very confusing situation to be confronted with and sobbers the mind completely. It comes as little wonder when you consider how accidents occur with this sort of failure(s).
Cudos to the OPs airline for understanding and exposing this type of occurrence. All crews should be confronted with this type of training. To combine it with upset recovery is also a fantastic idea as delayed recognition or as the OP suggests, operation withinin the limits of the aircraft flight envelope, may require the correct recovery technique to be applied.
It amazes me how many pilots appear bewildered when you mention the old adage, pitch x thrust = performance. It's disconcerting when you learn that so many are unaware of the importance of having a working knowledge of he fugures found within thr Performance Inflight section for flight with unreliable airspeed or the number one thing to do in a stall is to reduce the angle of attack. Seriously.
Credit to flyburg for posting his experiences in the sim, especially when he considers how he had felt humbled by the occurrence. However I'd be pretty sure that he now feels more confident about how to recognise and confront such a scenario, a scenario which in all likelihood has greater chances of occurring than an engine failure at V1.
Cudos to the OPs airline for understanding and exposing this type of occurrence. All crews should be confronted with this type of training. To combine it with upset recovery is also a fantastic idea as delayed recognition or as the OP suggests, operation withinin the limits of the aircraft flight envelope, may require the correct recovery technique to be applied.
It amazes me how many pilots appear bewildered when you mention the old adage, pitch x thrust = performance. It's disconcerting when you learn that so many are unaware of the importance of having a working knowledge of he fugures found within thr Performance Inflight section for flight with unreliable airspeed or the number one thing to do in a stall is to reduce the angle of attack. Seriously.
Credit to flyburg for posting his experiences in the sim, especially when he considers how he had felt humbled by the occurrence. However I'd be pretty sure that he now feels more confident about how to recognise and confront such a scenario, a scenario which in all likelihood has greater chances of occurring than an engine failure at V1.
Last edited by Callsign Kilo; 10th Jun 2012 at 08:07.
Also the values might be possible. When cruising at 230kts IAS while having an IAS reading of 30kts due to icing the difference would be 200kts (IAS/CAS), so the FMS would consider this difference as wind speed. However during your M1.1 adventure the wind speed reading should have been even quite a bit higher, especially, when being at a lower altitude if the IAS reading was still below 30kts.
Do you know how they did simulate the windspeed in the Sim? Is there a program to emulate all effects of pitot icing ? Or was it manually controlled by your examiner.
Interesting and enlighteneing story, btw.
regards, Henra
Last edited by henra; 10th Jun 2012 at 08:37.
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Low time cruise pilots
bubbers44 Quote " Hopefully we can stop the flow of low time cruise type pilots getting into the airlines, then monitoring autopilots and becoming captains with no actual flying experience hand flown. It probably isn't going to be allowed to happen because of the cost by the bean counters."
You are correct, of course. But although the bean counters love it, it is the regulator that allows this practice.
A well known airline based at the Fragrant Harbour uses low time Second Officers during criuse. These Second Officers do not even hold a full type rating, yet the aircraft is certificated to be operated by two pilots. This is criminal, in my opinion.
I wonder, then, what the definition of a pilot is.
I believe that the fare paying passenger has a right to expect two fully licenced and type rated pilots to be at the controls of the aircraft in which they are travelling.
Sadly, there are weak regulators who are nothing but whipping boys, merely endorsing the operator's demands.
The recently introduced MPL serves to illustrate the problem - it is not going to get any better, unfortunately.
You are correct, of course. But although the bean counters love it, it is the regulator that allows this practice.
A well known airline based at the Fragrant Harbour uses low time Second Officers during criuse. These Second Officers do not even hold a full type rating, yet the aircraft is certificated to be operated by two pilots. This is criminal, in my opinion.
I wonder, then, what the definition of a pilot is.
I believe that the fare paying passenger has a right to expect two fully licenced and type rated pilots to be at the controls of the aircraft in which they are travelling.
Sadly, there are weak regulators who are nothing but whipping boys, merely endorsing the operator's demands.
The recently introduced MPL serves to illustrate the problem - it is not going to get any better, unfortunately.
Last edited by FERetd; 10th Jun 2012 at 10:41.