B-738 Crash in Russia Rostov-on-Don

[Derfred]

Also, what use is a HUD during a go round, it's designed to allow you to follow the instruments while looking out. Why would you want to look out?

You obviously don't use one.

The 737NG HUD is designed to be used in all phases of flight. It reduces the instrument scan rate required during manual flight and generally results in much more accurate manual flight - including a go-around or windshear escape.

[Alycidon]

Thanks Derfred, no I don't use a HUD, so, the question is, on a go round, if you are using a HUD, climbing into an overcast at night with your landing lights on, will you not be distracted by the "cloud rush" as you enter the cloud?

A HUD is designed to allow you to aquire visual cues while still scanning the display, please indulge me and tell me what visual cues you would be looking for in a go round, and how you would avoid this distraction when climbing into the overcast with your lights on?

I would think that the impression of a false pitch up caused by somatographic illusion would be increased if you were seeing the cloud rushing past through the HUD as you climbed into the overcast, particularly if you have just been airborne for 6 hrs in the middle of the night.

Also, the PM does not have a HUD, so does not see the same picture and therefore will be using the PFD when not busy with flap/gear retraction or frequency changing and will not really be able to monitor the PF.

[noske]

Originally Posted by Chronus

The CVR is sacrosanct, very much doubt it would be released in full for public consumption.

What exactly do you mean? The CVR audio is indeed sacrosanct and has never been released for any accident, and I don't think that Sciolistes was asking for that, either.

Regarding CVR transcripts, the national agencies seem to have their traditional preferences. NTSB and BEA usually publish the full transcript (only with words "not related to the conduct of the flight" edited out), NTSC and MAK never do.

So you're probably right, we won't see the full transcript of this CVR, but only because that's how it's done in Russia.

[flash8]

... MAK never do.

So you're probably right, we won't see the full transcript of this CVR, but only because that's how it's done in Russia.

The pertinent parts will be leaked, that is for sure. That is how it is done in Russia.

Our friends in the desert though will have their sticky hands all over this...

[Derfred]

Alycidon,

Thanks Derfred, no I don't use a HUD, so, the question is, on a go round, if you are using a HUD, climbing into an overcast at night with your landing lights on, will you not be distracted by the "cloud rush" as you enter the cloud?

I have about a decade on 738 HUDs. I've never experienced that issue. I use the HUD for every takeoff including night into IMC. If you don't like it, you just shift your eyes down to the PFD - which you might do if taking off into the sun, for example, but it has never bothered me at night in cloud.

A HUD is designed to allow you to aquire visual cues while still scanning the display, please indulge me and tell me what visual cues you would be looking for in a go round, and how you would avoid this distraction when climbing into the overcast with your lights on?

Yes, acquiring visual cues during approach to land is a major design feature of the HUD, but as I said that is not it's only use. Obviously you are not looking for visual cues during a go-around (unless avoiding isolated CU's visually). As I said, the aircraft can be manually flown more accurately in all phases of flight using the HUD because of it's symbology, sensitivity and field of view. For this reason, HUD usage in all phases of flight is encouraged in my airline.

Following HUD guidance is like having a PFD maybe 10 times the size right in front of your eyes, complete with F/D guidance, FMA display, altitude, V/S, radio alt, speed, speed error (from bug), acceleration, all without the traditional instrument scan required on a PFD/ND.

We don't know whether the HUD was used for this manually flown G/A, but I am merely stating my opinion that if it was, it would not have been a contributing factor to the accident or any lack of S/A that may have occurred.

The HUD has a very clear horizon line stretching from left to right, making it very clear to a pilot looking at the HUD whether his nose is pointing up or down. Much more so than a PFD.

Furthermore, in a more extreme UA, the entire HUD picture changes to a circle with an arrow telling you which way you need to pitch in order to save the day. (If the AF447 pilot had one of these HUD's, it probably would have saved him). I digress, however, because it is possible that in this accident that by the time the aircraft was in a nose down UA, it was probably too late to save it.

I would think that the impression of a false pitch up caused by somatographic illusion would be increased if you were seeing the cloud rushing past through the HUD as you climbed into the overcast, particularly if you have just been airborne for 6 hrs in the middle of the night.

As I have said, I disagree. That's my opinion.

The HUD not only gives you pitch attitude, it gives you a flight path vector. If that flight path vector is above the horizon, you are going up. If it drops below the horizon, you are going down. I've already said the horizon is very obvious on the HUD, and the FPV is generally where your eyes will be focused, because that is what you "fly". If using F/D guidance, you fly the FPV to the F/D, rather than attitude as you would on a PFD.

Because you are left with no doubt about where your aircraft is going, I actually think somatogravic illusion is less likely with a HUD because you have better visual confirmation of what your aircraft is doing compared to what your vestibular system might be telling you.

Also, the PM does not have a HUD, so does not see the same picture and therefore will be using the PFD when not busy with flap/gear retraction or frequency changing and will not really be able to monitor the PF.

The PM does not have a HUD, but does see the same information! The PM sees the exact same aircraft pitch/speed/performance just on a different set of instruments. The F/D commands, if being followed during the G/A, will be the same on the PFD as they are in the HUD (different representation, but come from the same AFDS computer). If anything, two sets of eyes on two different instrument representations should increase redundancy (safety) not reduce it.

The PM's monitoring role is no different and no more or less important whether the PF is using a HUD or not. In fact the PM usually sits there in amazement (or jealousy) at how accurately the Captain is flying. The Captain is only flying more accurately because he has a more sensitive instrument that is easier to use (less scanning required).

The only time the PM misses out is during a low-viz manual landing (eg CAT III) because that is where having the HUD makes possible what would only otherwise be possible with autoland. Not relevant to this situation.

I will provide the caveat that the HUD requires training and practice for proficiency. I understand this crew was not new to the aircraft, but I know nothing of this airline's HUD training or HUD SOP's.

[sansmoteur]

Thanks Derfred, really informative.

[Chronus]

CVR

An important aspect of the CVR analysis will no doubt involve the differing nationalities of the flight crew. The captain, a Greek Cypriot and the FO a Spaniard. Therefore English not their mother tongue. Add to this Russian ATC. Might bring into question issues concerning communications, particularly at critical times. It is not always what is said but how it is said that may affect outcomes.

[Alycidon]

thanks Derfred, makes it much clearer, but even more of a mystery now.

[Vortex Thing]

Thank you Derfred. At last someone who knows and uses the HGS ( as some of us do everday) to stop me banging my head against the wall reading this thread. You beat me to the rebuttal there and to be fair did a better job of explaining the usage of the best thing since sliced bread in our cockpit than I would have done anyway!

[Derfred]

Thanks folks. I do have one more thing to add regarding the HUD - without wishing to derail this thread - I didn't mention this in my previous post because I was responding to the specific suggestion of somatogravic illusion.

The HUD exaggerates everything, compared to the traditional PFD, due to it's far greater size in the pilot's field of view, and therefore appears to be far more sensitive. This is why a HUD user can fly far more accurately.

However, this can "appear" to work against you in situations of moderate to severe turbulence. I say "appear" to work against you, but does it really?

For example, many years ago while I was learning the HUD in the simulator, we had to practice a severe approach windshear encounter using the HUD.

On the 737, the windshear escape manoeuvre, (after performing initial actions such as maximum thrust, 15deg pitch) recommends following F/D guidance - because the F/D has a "windshear mode" which gives very useful guidance. On the HUD, the F/D (or guidance cue as it is known in the HUD world) appears to dash all over the screen - as it responds immediately to every turbulent aircraft pitch and yaw - to the point where attempting to follow it appears to become an exercise in futility.

I said as much to the instructor after the event, having concluded already that I basically had no control over the aircraft using the HUD. He then asked the F/O what he thought of my efforts. The response was "extremely well handled". According to his PFD, I was flying the F/D very accurately, and the whole manoeuvre was very well flown.

The moral of this story is that using the HUD in severe turbulence or windshear might make you think you are flying badly, but in fact you are not. Your negative self-assessment is just due to the sensitivity of the instrument. Understanding this is critical to HUD proficiency.

Having said that, any experienced HUD pilot will know this, because they will have used the HUD during a many a turbulent approach to land, and learned not to over-control accordingly. They will also know that if they are not liking the HUD then they will automatically go eyes-to-the-PFD.

The aircraft involved in this accident was probably experiencing turbulence and maybe windshear. However, I personally can't conceive that HUD over-controlling was in any way a contributing factor to this accident. All the same, I just thought I'd end my HUD explanation with an honest and unbiased appraisal of the pros and cons of the instrument, and to point out again that training and experience is necessary to use a HUD.

[Alycidon]

Derfred, thanks again, to us non HGS equipped, this helps to understand why the HUD is a useful aid to safe flightpath management.

Vortex, sorry to have speculated about the use of the HGS without fully understanding the system, but according to the MAK interim report, there was a 12s APND trim input and we now know from Derfred that the HGS can be difficult to interpret in turbulence.

On the 737, the windshear escape manoeuvre, (after performing initial actions such as maximum thrust, 15deg pitch) recommends following useful guidance. On the HUD, the F/D (or guidance cue as it is known in theF/D guidance - because the F/D has a "windshear mode" which gives very HUD world) appears to dash all over the screen - as it responds immediately to every turbulent aircraft pitch and yaw - to the point where attempting to follow it appears to become an exercise in futility.

I said as much to the instructor after the event, having concluded already that I basically had no control over the aircraft using the HUD. He then asked the F/O what he thought of my efforts. The response was "extremely well handled". According to his PFD, I was flying the F/D very accurately, and the whole manoeuvre was very well flown

The RHS cannot use the HGS and the guidance is more sensitive than the PFD, so we have one pilot using one type of guidance system and the other pilot using a different one.

So, from your information regarding the HGS, is it not possible that a dual and opposing control input was the cause of the 12s nose down trim input, bearing in mind the crew must have been tired and somewhat stressed.

What would your views be on the cross cockpit co-ordination when both pilots are using different displays? The interim report does not mention whether the HUD was in use or not, but it would seem from the thread that it is SOP.

It also seems that the HUD/FGS requires a degree of currency, is it used for all approaches or just for LVOs?

The 737NG HUD is designed to be used in all phases of flight. It reduces the instrument scan rate required during manual flight and generally results in much more accurate manual flight - including a go-around or windshear escape.

In this case it didn't.


Thanks again for the informed comment.

[Chronus]

Derfred`s comments are most informative on the HUD. As the inferences drawn from known facts seem to point towards energy mismanagement, in the event the crew were reliant on HUD during the approach, would it not be reasonable to assume the HGS would have provided enhanced SA and energy management and would have alerted the crew from excessive and ill timed nose down pitch trim.

[MATELO]

737 HUD landing

https://www.youtube.com/watch?v=opiqvfrMGuc

[CHfour]

Waaayyy too much information for my old brain to process. I think I'll stick to my PFD and looking out of the window when it's nice and let George do the landing when its foggy.

[xollob]

that hud video is interesting, not much in the way of brown/blue though, 50 degrees nose down on a PFD would show a lot of brown, on the hud is there just a horizontal line for the horizon and no obvious colour pictorial ?

what's it like for unusual attitude recovery ?

[Chronus]

Bearing in mind we are talking about civil transport aircraft, if you mean brown on top and blue on bottom, some place like inside the marker on approach, then I`d guess it ain`t gone be much use.
Even in high performance combat aircraft ADI reference is a better guarantee against SD.
Here is some info on research conducted on the subject of HUD v Back up display in a static F18 sim.

http://www.lw.admin.ch/internet/luft...yhudvs.con.pdf

[recceguy]

Well, after reading all those posts of "experts" ... my input would be that it's quite difficult to say : HUD will do that, will induce those problems .... and PFD by the contrary ...
simply because it all depends of the MODEL of HUD you have, and the associated symbols displayed in it.
I've been flying HUD since 1984, a very advanced one which was changing a difficult aircraft into an easy one - simply because it was, and is still the best on the market. I flew after maybe 15 or 20 different ones, some of them really poor (horizon ? energy brackets ? FPV looking as a FPV when it simply was not...) Also the fact that the industry and the manufacturer can put anything they want in a HUD - well, in fact anything the test pilots want, and even the line pilots want. I have seen such ridiculous solutions "in order to prevent pilot disorientation" ....
Suffice to say that with a good HUD, you can make a barrel roll at low altitude in poor weather and horizon conditions, where you would have been killing yourself with the same aircraft without the HUD (yes, some had, and some hadn't)

Same for a HUD as for a head-down cockpit instrument : a nice one (russian, french often) will be a tremendous advantage, which will make you the pilot say "waoww.." when a poor design - such as some AOA indicators from anglo-saxon world - will make you move away from the stuff, with the assorted wrong conclusions. Did you know by example that you can find on the market HDI combined with HSI ?

When I became an airline pilot, I was so disappointed by how those aircraft were backwards. Then came, eventually and slowly, HUD for transport aircraft - and once again, some great, and some utterly complicated. Anyway, in cruise for hours they have nothing else to do than looking at it, and the approaches are always linear and simple, so I guess after some time they become familiar with the design, no matter how cluttered it might be..
So Derfred, sorry, your comment was about ONE type of HUD, not all the HUDs in general.

[framer]

Surely no pilot could ever do

a barrel roll at low altitude in poor weather and horizon conditions

To do that one would have to be an amazing pilot, one of the best there ever was.

[DOVES]

Chronus wrote:

An important aspect of the CVR analysis will no doubt involve the differing nationalities of the flight crew. The captain, a Greek Cypriot and the FO a Spaniard. Therefore English not their mother tongue. Add to this Russian ATC. Might bring into question issues concerning communications, particularly at critical times. It is not always what is said but how it is said that may affect outcomes.

AND:

- Call sign: Fly Dubai 981
- QFE 981
- 'Cleared 900 meters height'
- QNH 998

AND:

- Following HUD indications
- Landing Lights ext/ON in clouds

Is there any reasion for confusion?
More clearly than that?
It 's like a mute who wants to lead a blind in a forest.

[porterhouse]

when a poor design - such as some AOA indicators from anglo-saxon world

Disagree - AOA should always be there, specially in view of whole recent slew of accidents where AOA were busted. You don't want to watch AOA - fine, it occupies probably less than 2% of HUD display.