SFO- Asiana 777 crash

[Don t moderate me this way 882]

They still were fine 14 nm out, but it seems they had no real clue how to cope with the 180kts/5nm clearance - with or without the autopilot.

[january 19]

Q. from a rank amateur- I wonder what role, thermal air currents may play in landing at KSFO ?

Imagine a hot sunny day with a light & cool westerly breeze from the sea.

Thermal currents would be rising from scorching hot runways and then would be pushed easterly over the Bay into the path of a descending aircraft- giving it an unexpected lift.

This rising warm air mass however would be cooling on its underside by the frigid waters of the bay and thus would be falling.

An aircraft on approach would first experience unexpected lift as it penetrated the thermal - and then perhaps quite suddenly, experience loss of lift- at the very moment when a stable path is most needed.

A sudden reversal of apparent lift that might surprise an unwary pilot????

january

 

[vololiberista 205]

Q. from a rank amateur- I wonder what role, thermal air currents may play in landing at KSFO ?

Imagine a hot sunny day with a light & cool westerly breeze from the sea.

Thermal currents would be rising from scorching hot runways and then would be pushed easterly over the Bay into the path of a descending aircraft- giving it an unexpected lift.

This rising warm air mass however would be cooling on its underside by the frigid waters of the bay and thus would be falling.

An aircraft on approach would first experience unexpected lift as it penetrated the thermal - and then perhaps quite suddenly, experience loss of lift- at the very moment when a stable path is most needed.

A sudden reversal of apparent lift that might surprise an unwary pilot????

january

This is why jet engines should never be allowed to spool down to idle during an approach. They take too long to recover (compared to propellers that immedaitely increase the airflow over the wings) in which time the aircraft has sunk further with ensuing consequences!

 

The aircraft in the article below was producing at least 82% n2 if not more in order to power away safely as it did!

 

http://www.vc10.net/Memories/testing_earlydays.html#GARVM%20at%20White%20Waltham

[FLEX1978 373]

Q. from a rank amateur- I wonder what role, thermal air currents may play in landing at KSFO ?

Imagine a hot sunny day with a light & cool westerly breeze from the sea.

Thermal currents would be rising from scorching hot runways and then would be pushed easterly over the Bay into the path of a descending aircraft- giving it an unexpected lift.

This rising warm air mass however would be cooling on its underside by the frigid waters of the bay and thus would be falling.

An aircraft on approach would first experience unexpected lift as it penetrated the thermal - and then perhaps quite suddenly, experience loss of lift- at the very moment when a stable path is most needed.

A sudden reversal of apparent lift that might surprise an unwary pilot????

january

 

Well it's just like landing anywhere else in the world. Take a look at Hong Kong, Narita, Gibraltar & many other airfields. Updrafts/downdrafts,  severe turbulence etc are all covered in the notes section of the charts.  It's all part of being a professional pilot.    

 

The 777 also has predictive windshear, first sign of a problem and you hit TOGA.

[KevinAu 441]

They still were fine 14 nm out, but it seems they had no real clue how to cope with the 180kts/5nm clearance - with or without the autopilot.

An instruction like that should have never been accepted by the pilots. A factor that never seems to get proper recognition in these kinds of accidents is the contribution played by the controllers in setting up a crew for a high and fast approach. In the end, the crew has final responsibility, but if blame is to be apportioned out to others that weren't actually in the cockpit, such as Boeing, ATC should share some of that blame as well.

[FLEX1978 373]

An instruction like that should have never been accepted by the pilots. A factor that never seems to get proper recognition in these kinds of accidents is the contribution played by the controllers in setting up a crew for a high and fast approach. In the end, the crew has final responsibility, but if blame is to be apportioned out to others that weren't actually in the cockpit, such as Boeing, ATC should share some of that blame as well.

 

It does get recognition, not sure why you would think otherwise? How exactly can ATC be blamed? Nothing about the approach path was dangerous or beyond the capability of the aircraft. The crew mismanaged the aircraft's energy state and ignored warnings. 

 

Everyone one else that day managed to get down safely with the G/S inop.

[KevinAu 441]

I didn't see it in the report. Maybe I missed it. Yes others made it down just fine. Just because I'm a hot stick and can get my plane down from a 3000 foot start inside of ten miles doesn't mean that everything is fine. The problem with us pilots is that we are mostly type A individuals who will not let a challenge go unconquered. Therefore when the controllers set up aircrafy for the initiation of their landing approaches way outside safe parameters and then the pilots accept it and 'make it work', it just makes them think that it is ok to keep setting up people for high energy approaches. While in the cockpit, the crews are usually violating stabilized approach company rules to make the approach work. If controllers start getting a portion of blame each time an aircraft under their control had an accident from a high energy approach, they'll be a little more concerned about vectoring their planes correctly for a safe approach instead of just squeezing as many planes in as they can.

 

The glideslope being inop had little to do with it. They crashed because they started that approach from a high and fast position, which led them into using guidance modes that they would not normally be using at that stage of flight and then became preoccupied with staring out the window wondering if they were going to get down in time.

[FLEX1978 373]

While in the cockpit, the crews are usually violating stabilized approach company rules to make the approach work

 

How does that work? You bust stable approach criteria & the QAR picks it up. Next thing you have is a trip to the office to explain yourself. I hope you are not saying you & your company tolerate busting SOP?

 

Crew deal with high energy approaches all over the world for a number of reasons. If anyone feels they are unable to deal with the extra workload they should not be near the flight deck of an airliner.  

 

You as the pilot have the last say, if it is beyond the safe operation of the aircraft you say unable or Go-around, and if you find yourself in the same mess as the Asiana crew you most definitely fly the missed approach and get yourself stable earlier.

 

They could have gone around, programmed the RNAV GPS approach back to 28L and landed without any issues. 

 

This is basic stuff.

[KevinAu 441]

How does that work? You bust stable approach criteria & the QAR picks it up. Next thing you have is a trip to the office to explain yourself. I hope you are not saying you & your company tolerate busting SOP?

 

Crew deal with high energy approaches all over the world for a number of reasons. If anyone feels they are unable to deal with the extra workload they should not be near the flight deck of an airliner.

 

You as the pilot have the last say, if it is beyond the safe operation of the aircraft you say unable or Go-around, and if you find yourself in the same mess as the Asiana crew you most definitely fly the missed approach.

 

This is basic stuff.

And ATC is probably the most common reason for unstabilized approaches.

 

You'd think people would say 'unable' when they should. Then we wouldn't have these kinds of accidents. If these Asiana guys or the Air France guys or the Colgan guys had the basics down, these boards wouldn't be as lively. I've flown with enough people to know not to expect everybody in professional aviation to belong there. So why not remove one more element of risk by having controllers vectors plane with safety in mind instead of airport arrival rate?

[Mike777 163]

I agree with the criticisms that have been leveled against the pilots, their poor knowledge of the systems, poor CRM, poor training, sheer inattention at a crucial moment.  Moreover, even if the autothrottle had been designed to control speed in their situation, they still needed to monitor airspeed on final approach.  After all, any system can fail at any time, including the autothrottle.

That being said, and at the risk of being flamed, I do not understand why the autothrottle, as long as it is armed,  is designed to ever not “wake up” while in the air if the airspeed threatens to drop below minimum safe flying speed for that configuration.  After all, it does wake up automatically in some situations – and it does so precisely to counteract pilot error/inattention, among other things.
    
I am not talking about HOLD mode during the takeoff role.  In VNAV SPD, I believe I understand why the autothrottle goes into HOLD (to allow the pilot to modify the rate of descent by varying the thrust).  But even in that situation, why would it ever remain there if the aircraft dropped to or below minimum safe flying speed (i.e. approached a stall)?  I am not suggesting that it go into TOGA, but rather that it should always seek to add enough thrust to prevent a stall (except during the last few feet of a landing).  In short, under what conceivable circumstances, while in the air and not on very, very short final (perhaps 25-50 ft AGL) is it better to allow the pilot to reduce speed to at or below stall speed than to override his/her decision by applying enough thrust to maintain minimum safe flying speed?

This is quite different from roll and pitch modes where it does make sense for the pilot to be able to override the autoprotections.  For example, if I remember correctly, Captain Sullenberger was unable to flare as much as he wanted to because alpha protection on his Airbus prevented the aircraft from a potential stall by going further nose up.  In that situation my money would be on Captain Sullenberger.  The autoprotection logic could not anticipate a no-engine/gear up water landing.  
 

Mike

[Don t moderate me this way 882]

The NTSB abstract says:

 

"FINDINGS

1. The following were not factors in the accident: (...); or the air traffic controllers’ handling of the flight. (...)"

 

My rough estimate is that the crew had about 75 seconds to decelerate from 180 kts to some 140 kts during a 3° descent (with the gear down and a good amount of flaps extended). I'm no pilot, but this 'feels' as if it should have been possible.

[FLEX1978 373]

Hi Mike, 

 

If you speak to most people they will tell you the protections helped Capt  Sully, a nice example of man and machine working together.  The aircraft remained in normal law because the engines where still running and producing thrust (idle) if both engines actually died he would have been in alternate law and the outcome could have been very different.

 

Regarding the 777  A/T logic - It is a called a trap for a reason and has been commented on way before the Asiana incident.   Both Airbus & Boeing have quirks and a different operating philosophy, those up from are trusted to understand and operate these machines within their limitations, and most importantly understand how every mode works.

 

The A320  has  little traps, you must disengage both FD's when hand flying and not following a computed path, especially in OP CLB or DES  (Airbus version of FLCH) if you don't switch of the FD you can get yourself into a lot of trouble and trigger Alpha floor.

 

Here's a classic and fatal example - http://flightsafety.org/ap/ap_jan94.pdf

 

If you know any real world airbus drivers ask them what happens if you take off using FLX/MCT and then select TOGA for what ever reason below the acceleration altitude. The aircraft will command a go-around during take off!

 

None of these traps 'as some like to call them' are an issue if you understand how the aircraft works. Clearly the Asiana crew didn't,  hand flying FLCH with idle thrust below 500ft in HOLD & the FD's on is asking to become a statistic.

[KevinAu 441]

The NTSB abstract says:

 

"FINDINGS

• The following were not factors in the accident: (...); or the air traffic controllers’ handling of the flight. (...)"

My rough estimate is that the crew had about 75 seconds to decelerate from 180 kts to some 140 kts during a 3° descent (with the gear down and a good amount of flaps extended). I'm no pilot, but this 'feels' as if it should have been possible.

Which us exactly my point. ATC always gets off scot free.

 

If I remember what I read about this accident correctly, they had a high base start to this visual, so they were pretty much preoccupied with getting down and slowing down.

[evaamo 549]

Kevin, I understand your point. But when you are the *captain* of any aircraft, even more so if responsible for the safety of +300 souls, you should never comply with an ATC instruction that puts lives in danger.

 

It's likely we wouldn't even be discussing this event had the crew called for a go-around in a timely fashion or just replied a simple "unable" if they felt the instruction could compromise the flight's safety. The F/O was a seasoned 777 driver. The PF (and *captain*!!!) of the aircraft was indeed new to the 777, but he was anything but a newbie pilot. IIRC he had more than 18.000 hours of flight time. Any pilot with such experience, regardless of his/her proficiency level in the aircraft, should have known better than to continue with the landing.

 

This accident reminds me of a friend of mine who was first officer for a commuter airline. A series of events such as the need to comply with the airline schedule to avoid delay fines, the rush to take advantage of an ATC clearance window and the "must to carry on" with the captain's "Gotta Landitis" (hat tip Oliver for such a real world phrase!) ended up in an accident that claimed my buddy's (in his early twenties) and another 43 lives.

[Tom Allensworth 1,532]

This discussion and the apportionment of blame leaves one very BIG factor out... That is the culture of age, seniority and "respect" inherent in the Korean culture. The PF (and the trainee) was the senior officer aboard, if my memory serves, and everyone deferred to him. Someone mentioned the lack of response from the F/O. My assumption is that this cultural  was the reason he was less than assertive. In fact, I would be willing to guess that the entire CRM and training system is replete with potential disasters waiting to happen because of it. My opinion; a very high percentage of cause for this accident rests with the culture.