Asiana B-777 Reported Down At KSFO

[Don t moderate me this way 882]

You mean pitch stable ? Because I don't see the 777 automatically pitching +15 or -15 degrees to keep the glide slope with idle or full throttle setting.

 

All I know about FBW, is the airbus one and it will allow you to lock your pitch and roll input, with auto-trim and auto throttle will try its best to maintain the selected speed.

 

The Cessna 172 handle like all the others non exotic airplanes ever made, the exception of FBW plane, but the logic should not be different at all

 

I'm not sure about maintaining the turn rate but it does keep the pitch by use of autotrim. So changing thrust does not change your descent path.

 

The Asiana was not in an automatic approach mode as the G/S was INOP. Speed dropping into the stall area is still one of those riddles that have to be resolved.

Is it safe to say, that if the plane did not suffers mechanical problems and it was allowed to get bellow vref, than the A/T was in fact disconnected ?

 

Even an armed but not engaged A/THR on the 777 has the ability to deliver thrust when approaching a stall (FBW stall protection). It seems that engine or fuel problems were no issue here, as the engines were able to spool up when throttles were moved manually (too late, though).

 

It could still be (1) a mechanical/electronic problem related to the automation or (2.a) a lesser degree of automation selected by the pilots (A/THR not even armed), combined with (2.b ) bad basic airmenship.

A third possibility (3.a) is an unfortunate (and probably inappropriate) selection of automatic modes (FLCH) without being aware (3.b ) that FLCH inhibits the throttle wake up even with A/THR engaged.

 

Apart from all that there's still the question why the PM (monitoring airspeed primarily) did not advise the PF of the decaying airspeed.

 

Many open questions still ...

[bendead 1,085]

So changing thrust does not change your descent path.

 

No ! It will not change your pitch, but with throttles at idle your glide slope will be flatter and flatter and flatter until you crash

[FLEX1978 373]

You mean pitch stable ? Because I don't see the 777 automatically pitching +15 or -15 degrees to keep the glide slope with idle or full throttle setting.

All I know about FBW, is the airbus one and it will allow you to lock your pitch and roll input, with auto-trim and auto throttle will try its best to maintain the selected speed.

 

The Cessna 172 handle like all the others non exotic airplanes ever made, the exception of FBW plane, but the logic should not be different at all

The 777 will adjust pitch automatically to maintain the referenced trim speed, if you slow down it will pitch down, increase speed it will pitch up. Also no change in pitch when you configure the gear or flaps.

 

Just to add, if you try to manually trim a 777 in flight you are not actually moving the trim tabs, you move the elevator then the aircraft automatically trims to the new referance speed

[bendead 1,085]

The Asiana was not in an automatic approach mode as the G/S was INOP.

 

It was INOP, but it was a visual approach, and I would have done the same thing as they did, too high too fast, close the throttle and pitch down, wait until glide is ok then reduce your speed and re setup for a normal approach

[Don t moderate me this way 882]

No ! It will not change your pitch, but with throttles at idle your glide slope will be flatter and flatter and flatter until you crash

 

 

Wait!

 

- No glide slope was active during the accident. You're talking about the descent path.

- And depending on how steep your descent is, you may not need thrust above idle at all.

It was INOP, but it was a visual approach, and I would have done the same thing as they did, too high too fast, close the throttle and pitch down, wait until glide is ok then reduce your speed and re setup for a normal approach

 

 

And when your altitude/descent rate are back within tolerable margins you would pay a lot of attention to your speed and thrust ...

[bendead 1,085]

The 777 will adjust pitch automatically to maintain the referenced trim speed, if you slow down it will pitch down, increase speed it will pitch up. Also no change in pitch when you configure the gear or flaps.

 

Just to add, if you try to manually trim a 777 in flight you are not actually moving the trim tabs, you move the elevator then the aircraft automatically trims to the new referance speed

 

My friend from AS, just joking

 

It is doing that because the throttles are at maximum / minimum or just together with it ?

[bo3bber 0]

Some high resolution photos directly from NTSB.

 

http://www.flickr.com/photos/68618467@N03/sets/72157634528378705/

[bendead 1,085]

- No glide slope was active during the accident. You're talking about the descent path.

 

Yeah, it a visual interpretation of your glide path, the runway perspective changes with the length or width of the runway, but you are trained to that on your PPL/CPL

- And depending on how steep your descent is, you may not need thrust above idle at all.

 

I know and I did a couple of landing at idle, you just have to know when to adjust your power, idle approach with full power closed to the runway is called a rubbish but successful landing

And when your altitude/descent rate are back within tolerable margins you would pay a lot of attention to your speed and thrust ...

 

Eyes on the runway to check if my profile is correct again, snapshot my ASI a few time and land the plane

[Don t moderate me this way 882]

Yeah, it a visual interpretation of your glide path, the runway perspective changes with the length or width of the runway, but you are trained to that on your PPL/CPL

 

I know and I did a couple of landing at idle, you just have to know when to adjust your power, idle approach with full power closed to the runway is called a rubbish but successful landing

 

Eyes on the runway to check if my profile is correct again, snapshot my ASI a few time and land the plane

 

 

Now you're all set to apply for a flight instructor job at Asiana ...  

[KevinAu 441]

My bad, I though you were talking about altitude callouts only.

 

Regarding the visual approach discussion, I am sitting here listening to Perth Approach, who is issuing clearances for visual approaches only. The current METAR is FEW042, 9999 vis. Last night, they were also doing visual approaches, so it definitely isn't out of the ordinary to do a visual apch.

You misunderstand what I wrote. The discussion about visual approaches was about visual approaches to runways that have no instrument approach procedure backup. I fly E190s for a major in the US, I know I do plenty of visual approaches everyday and night. However, I am able to do almost all of those with a published ILS or other type of published approach programmed in the box and tuned to the radios to provide guidance on my displays while I make my visual. It is the rare approach to a runway that has no such support that I was having the discussion with Ro about.

[bendead 1,085]

Now you're all set to apply for a flight instructor job at Asiana ...  

 

LOL :lol:  My instructor should, really.

 

One thing very important I learn is, f*ck the checklist, just fly the plane and even think a few minutes before you do a thing, so you will know the result.

 

If you buy me a FFB yoke, a nice setup to fly the PMDG 777 and I would not fly "RW" for a few month. I would suck at flying again.

[fencer 16]

My two cents on the topic :

Korean flight deck culture :

We're not talking about a junior FO/senior captain relationship here as both pilots were pretty senior so let's wait until we know more before jumping to conclusions.

Visual vs instrument approaches

1 Apparently the PAPI was operating correctly

2 I understand both Kevin's and Ró's points...and happen to agree with both (By the way IAF 747, both of them fly airliners for a living so I am sure your advice and flying tips to Kevin are duly appreciated).

A minor point : maybe the word "threat" to qualify a visual approach should have been replaced by another one ("potential risk" ? or "potential threat when not practiced regularly"). And (Ró), to me a threat is not necessarily something beyond my control, it 's just a threat that, with the proper attitude, technique, training - and sometimes luck - I'll be able to overcome.

By the way, with the limitated resolution of our computer screens, try a visual approach in FS without ANY navigation aid (ie no distance info, no PAPI etc) and you'll understand Kevin's point. But , if I agree with Ró's point that doing it often should make this a rather simple task, I also guess that after a long night flight, many captains will prefer to land in AUTO mode.

Glad to see some posters trying to revive the good old "stick vs throttle" debate about speed control in FINAL.

Suffice to remember that A.T. controls SPEED and that MOST airline pilots will use throttle to control speed in final....

In closing, a thought for the victims of this tragic mishap and for their families.

Rgds,

Bruno

PS (edit) : Rón, what's RHS ? Right Hand Seat?

[bendead 1,085]

But I agree with Ró's point that doing it often should make this a rather simple task.

 

Practice makes perfect. I am just wondering if Ró's is practicing GA anymore

[bendead 1,085]

Suffice to remember that A.T. controls SPEED and that MOST airline pilots will use throttle to control speed in final....

 

Not really, it controls thrust, which will give you a different glide slope more than a speed increase on final

[Don t moderate me this way 882]

Not really, it controls thrust, which will give you a different glide slope more than a speed increase on final

 

 

That's where some of the recent confusion in this thread comes from:

 

- A/THR has different modes: speed and thrust, depending on the vertical mode you choose