Orient Thai plunges from sky after engine fails

[JoeLing]

AFAIK the f-16 is the world's only plane whose maximum engine thrust exceeds its weight (which varies of course) so it can theoretically fly straight up like a rocket. But even one of those can stall out.

They still fly the Lightning at air shows I think. Watched exactly that in awe when I was a kid.

I understand the English Electric P1 Lightning could go through the sound barrier in straight up vertical flight.

Unless Orient Thai flies their customers in F-16 or the "English Electric P1"

I can not see any relevance to this thread.

Can you enlighten me? Clarification?

[F4UCorsair]

Someone told me once that 777-200 can fly up vertical if it's has no passengers or cargo so powerful are the two engines. Don't know if its ever been done, Boeing might have done it during testing? Aviation myth?

It is quite powerful but not that powerful.

B777-200; empty weight about 300,000 lbs, thrust up to 2x 100,000 lbs.

B777-300ER; thrust 2x 115,000 lbs, but empty weight 370,000 lbs.

Mr Y, you are right only if it was achieved from maximum speed and pulled vertical, but it can't be sustained.

The key to it is that total thrust must equal the weight of the aircraft at the time to maintain vertical flight. To climb vertically, the thrust must be greater than the weight.

[soalbundy]

I always assumed forward momentum and glide ratio would prevent a plane from falling from the sky?

It's like Einsteins theory of relativity, it depends on whether you are in the aircraft or watching it from the ground as a neutral observer.

[Alfred Gruetzner]

Good pilots are able to handle an engine failure during cruising speed in a way that the passengers do not even feel that something is wrong. But it is necessary to check the instruments constantly. If the plane starts to stall then it is obvious: Unawarness of the flying crew! Can be deadly. If the plane - for example - has a speed of 600 nm - then an engine failure will not put the plane immediately in a stall situation, The crew has ample time to react. If the plane is in take off situation the crew might handle this much better, because they are, have to, constantly observing the engine instruments and know what to do if an engine shuts down.

If you have the engines on the wing and 1 fails, wouldn't the airplane make a sharp turn, which may cause some other problems. And what would the autopilot do in such a situation?

no, no sharp thurn, but if one of the outer engines is out then the pilot must

stabilize the plane immediately. The pilot will deactivate the autopilot for that, fly by hand for some time,

will look for the next airport in the vicinity and land there as an emergency

landing. This procedure is standard. But why the plane fell thousands of feet down

has different reasons. May be has be flown too high up. The plane might have been

above 40000 feet and was therefore in the so called "coffin corner" where the

minimumspeed and the maximum speed are very near together, so it is possible that the

plane comes into a stall situation and falls from the sky like a stone. Very rare.

But happened many years ago with China airlines over the pacific for example but they

managed to stabilize the plane 10000 feet over water....Another reason may have been

an windshear - too much wind form the tail . In this situation planes also come into a stall

situation as well. But who knows what really happened.

[Loles]

Crying staff is not the best thing on board when the aircraft is in trouble. I guess if they have to use the emergency sliders the staff would been the first who left the plane ... brave people.

[sandyf]

They do not build them like this anymore. Aircraft is about 10 feet off the ground an the shot was taken by the navigator in a similar aircraft coming in the opposite direction. This was taken in Malta but I did witness a similar move in the UK by a pilot that was retiring.

Edited April 2, 2015 by sandyf

[harrry]

I'm a pilot that often flies a twin-engine aircraft and I can assure you that when an engine fails, the aircraft doesn't just "plunge out of the sky". If the pilot responds to it quickly, chances are passengers won't even notice (depending on the aircraft type). Planes can fly fine on one engine, especially if they are already straight and level at altitude.

Perhaps there was also depressurisation issues, hence the rapid descent and oxygen masks. It wouldn't just nose dive due to a single engine failure.

huh..... yes it would if both pilots were crying "da plane da plane" & slapping their head.....:-)

If if it was an AIrbus the pilots would have been looking at each other and saying: "What the hell is the plane doing now?" .

[maidee]

professional thai crew, start the panic first

[Tomtomtom69]

Report on the flight http://avherald.com/h?article=483fc32e

Hard to believe this airline is still in existence with their 1-2-Go debacle in Phuket. Couldn't pay me to get on one of their aircraft.

http://en.wikipedia.org/wiki/One-Two-GO_Airlines_Flight_269

"Well used" aircraft http://www.airfleets.net/ageflotte/Orient%20Thai%20Airlines.htm

I couldn't agree more. That company utilise nothing but flying coffins. Anyone who flies with them needs their head examining in my opinion.

As I recall it was Orient Thai had bought the 747 that crashed on its last flight with China Airways ( CI 611).

That can't be right, that flight was a complete hull loss, it crashed into the Taiwan strait between Taiwan and Hong Kong in 2002, didn't it? No way that aircraft could have been repaired and probably only a fraction of the aircraft fuselage would have even been recovered.

UNLESS you mean the flight that dropped thousands of metres/feet over the Pacific Ocean en-route from Taiwan to Los Angeles, that had to make an emergency landing in San Fran? That aircraft had part of it's tail ripped off but was otherwise intact.

Sorry I could have just checked the flight numbers to confirm which flight it was, but too lazy. So just wondering.

Edited April 2, 2015 by Tomtomtom69

[55Jay]

Good pilots are able to handle an engine failure during cruising speed in a way that the passengers do not even feel that something is wrong. But it is necessary to check the instruments constantly. If the plane starts to stall then it is obvious: Unawarness of the flying crew! Can be deadly. If the plane - for example - has a speed of 600 nm - then an engine failure will not put the plane immediately in a stall situation, The crew has ample time to react. If the plane is in take off situation the crew might handle this much better, because they are, have to, constantly observing the engine instruments and know what to do if an engine shuts down.

If you have the engines on the wing and 1 fails, wouldn't the airplane make a sharp turn, which may cause some other problems. And what would the autopilot do in such a situation?

no, no sharp thurn, but if one of the outer engines is out then the pilot must

stabilize the plane immediately. The pilot will deactivate the autopilot for that, fly by hand for some time,

will look for the next airport in the vicinity and land there as an emergency

landing. This procedure is standard. But why the plane fell thousands of feet down

has different reasons. May be has be flown too high up. The plane might have been

above 40000 feet and was therefore in the so called "coffin corner" where the

minimumspeed and the maximum speed are very near together, so it is possible that the

plane comes into a stall situation and falls from the sky like a stone. Very rare.

But happened many years ago with China airlines over the pacific for example but they

managed to stabilize the plane 10000 feet over water....Another reason may have been

an windshear - too much wind form the tail . In this situation planes also come into a stall

situation as well. But who knows what really happened.

No need to speculate. The details are available on this thread and on other internet sites.

[fritzzz25]

Report on the flight http://avherald.com/h?article=483fc32e

Hard to believe this airline is still in existence with their 1-2-Go debacle in Phuket. Couldn't pay me to get on one of their aircraft.

http://en.wikipedia.org/wiki/One-Two-GO_Airlines_Flight_269

"Well used" aircraft http://www.airfleets.net/ageflotte/Orient%20Thai%20Airlines.htm

I couldn't agree more. That company utilise nothing but flying coffins. Anyone who flies with them needs their head examining in my opinion.

As I recall it was Orient Thai had bought the 747 that crashed on its last flight with China Airways ( CI 611).

That can't be right, that flight was a complete hull loss, it crashed into the Taiwan strait between Taiwan and Hong Kong in 2002, didn't it? No way that aircraft could have been repaired and probably only a fraction of the aircraft fuselage would have even been recovered.

UNLESS you mean the flight that dropped thousands of metres/feet over the Pacific Ocean en-route from Taiwan to Los Angeles, that had to make an emergency landing in San Fran? That aircraft had part of it's tail ripped off but was otherwise intact.

Sorry I could have just checked the flight numbers to confirm which flight it was, but too lazy. So just wondering.

Orient Thai has never purchased any 747 that was ever flown by China Airlines. http://www.airfleets.net/flottecie/Orient%20Thai%20Airlines.htm shows you all of the aircraft they have ever owned.

The incident aircraft over the Pacific that is mentioned with the emergency ladning at SFO is this aircraft http://www.747sp.com/production-list/22805-564/

[CNXBKKMAN]

I remember reading an article a couple of years back about Midway Island out in the pacific. It was saying it used to be a busy stop for airliners crossing the pacific but nowadays with the increased range of modern aircraft there's no need to stop. The airport is quiet, it's a remote backwater. The world passes it by. The funny thing was when the journalist wrote the article there was an airliner present, a 747. The airport staff said that was emergency diversion during a delivery flight. It was a "new" Orient Thai 747 on its way to BKK. Technical fault on its first flight for Orient Thai.

[Johnny S]

Crying staff is not the best thing on board when the aircraft is in trouble. I guess if they have to use the emergency sliders the staff would been the first who left the plane ... brave people.

Agree - Fire them if they cant handle an emergency, thats what they are there for - not to serve coffee

[MaxYakov]

I always assumed forward momentum and glide ratio would prevent a plane from falling from the sky?

I can't tell if you are asking us if you assumed something or are asking a question about what you assumed.

Anyway, it got a lot of likes and a few oblique answers so I'll try to answer as well. The terms "forward momentum" and "glide ratio" might be better applied to a glider. In this case it was a jet airliner at cruise altitude losing half of its available thrust due to an engine failure so it's quite a bit different. I rummaged around and found these well-written postings from an "Engine failure during cruise" thread on PPRuNe (Professional Pilot's Rumor Network):

"You remember from your studies that in unaccelerated steady flight, constant airspeed, thrust equals drag.

If your Boeing 737 NG is flying at cruise altitude and your airspeed is stable at a given mach, say .78, the thrust of your engines equal the drag generated by your airplane. Now if one of your two engines fails; and you do nothing but maintain altitude, very quickly the airspeed will begin to slow (decay).

The airspeed will slow because you have 50% of the thrust you had before the engine failure, all the drag you previously had plus you have added the drag created by the inoperative engine wind milling in the air. Your thrust was reduced by 50% and your drag increased significantly. Your airspeed will decay. If you do nothing but try to maintain altitude with pitch, you will stall."

There are a few ways to "stall" an aircraft at cruise, BTW, without losing engine power as was demonstrated by the pilots flying AF 447, but I digress. In a stall, the aircraft is falling because the lift of the wings has been lost, regardless of the plane's forward momentum. The momentum at that point will be mainly downward as the lift of the wings cannot offset the acceleration of gravity. A stall occurs when the "Angle of Attack" of the wings relative to the airstream is too great and wing lift is lost.

If the above strikes you as a little too technical, then here is (allegedly) the single-engine failure procedure for a Boeing 737 Flight Crew Training Manual from the same thread:

"If an engine failure occurs at cruise altitude, it may be necessary to descend. The autothrottle should be disconnected and the thrust manually set to CON. On the FMC CRZ page select the ENG OUT prompt, followed by the prompt corresponding to the failed engine. This displays the engine out cruise data and the FMC calculates engine out target speed and maximum engine out altitude at the current gross weight. The fields are updated as fuel is burned. Do not execute the page if VNAV is required for any arrival procedures. If any ENG OUT page is executed then FMC will not transition to descent.

Set the maximum altitude in the MCP altitude window and the engine out target airspeed in the MCP IAS window. Allow airspeed to slow to engine out speed then engage LVL CHG. If the "Engine Out Target Airspeed" and "Maximum Continuous Thrust" are maintained, the airplane levels off above the original MAX altitude. However the updated MAX altitude is displayed on the ENG OUT CRZ page. After viewing the engine out data, select the ERASE prompt to return to the active cruise page.

After level off at the target altitude, maintain MCT and allow the airplane to accelerate to the single engine long range cruise speed. Maintain this speed with manual thrust adjustment. Entering the new cruise altitude and airspeed on the ECON CRZ page updates the ETAs and TOD predictions."

There may have been associated issues such as cabin pressurization concerns to cause the flight crew to make such a rapid descent. This was an incident that should have been reported and investigated. I cannot second guess their decision to perform a scary, rapid descent, but I have my suspicion that they may have overreacted to the engine failure. Everyone survived so even it was not the ideal decision, it wasn't the worst case scenario.

Edited April 2, 2015 by MaxYakov

[MrY]

As I recall it was Orient Thai had bought the 747 that crashed on its last flight with China Airways ( CI 611).

That can't be right, that flight was a complete hull loss, it crashed into the Taiwan strait between Taiwan and Hong Kong in 2002, didn't it? No way that aircraft could have been repaired and probably only a fraction of the aircraft fuselage would have even been recovered.

UNLESS you mean the flight that dropped thousands of metres/feet over the Pacific Ocean en-route from Taiwan to Los Angeles, that had to make an emergency landing in San Fran? That aircraft had part of it's tail ripped off but was otherwise intact.

Sorry I could have just checked the flight numbers to confirm which flight it was, but too lazy. So just wondering.

Orient Thai has never purchased any 747 that was ever flown by China Airlines. http://www.airfleets.net/flottecie/Orient%20Thai%20Airlines.htm shows you all of the aircraft they have ever owned.

The incident aircraft over the Pacific that is mentioned with the emergency ladning at SFO is this aircraft http://www.747sp.com/production-list/22805-564/

Orient Thai had bought the aircraft, but it had not been taken out of service with China Airlines yet.

[PaPiPuPePo]

AFAIK the f-16 is the world's only plane whose maximum engine thrust exceeds its weight (which varies of course) so it can theoretically fly straight up like a rocket. But even one of those can stall out.

They still fly the Lightning at air shows I think. Watched exactly that in awe when I was a kid.

Well (at to FH above) I _did_ write "as far as I know," which is apparently not very far

[NeverSure]

I always assumed forward momentum and glide ratio would prevent a plane from falling from the sky?

There have been some correct but complicated answers to this. In pilot-speak it's called "trading speed for altitude". If you are lacking power and put the nose a bit down, the plane will maintain enough speed to glide, but you have to give up that altitude to do it. If properly handled there's no danger of falling out of the sky as the plane maintains its normal power-off glide slope. There is an assurance of descending in a controlled glide, but the plane remains controllable to the point of being able to land it if a suitable place is within reach.

Every plane has an optimum glide speed and that depends also on its load (weight) and a couple of other factors. The pilots will watch the airspeed and maintain that airspeed by pulling the nose up or lowering it. Properly done this will give them the longest glide and the slowest, softest practical landing.

[MaxYakov]

I always assumed forward momentum and glide ratio would prevent a plane from falling from the sky?

There have been some correct but complicated answers to this. In pilot-speak it's called "trading speed for altitude". If you are lacking power and put the nose a bit down, the plane will maintain enough speed to glide, but you have to give up that altitude to do it. If properly handled there's no danger of falling out of the sky as the plane maintains its normal power-off glide slope. There is an assurance of descending in a controlled glide, but the plane remains controllable to the point of being able to land it if a suitable place is within reach.

Every plane has an optimum glide speed and that depends also on its load (weight) and a couple of other factors. The pilots will watch the airspeed and maintain that airspeed by pulling the nose up or lowering it. Properly done this will give them the longest glide and the slowest, softest practical landing.

Actually, just like a glider between thermals or updrafts, the pilot of a powered aircraft that has lost all engines has to "trade altitude for distance (and, to a degree, speed)". The optimum glide speed of the aircraft is specific to the aircraft type and the optimum glide-distance possible is dependent on several factors such as aircraft design, aircraft drag, wind direction (relative to the aircraft's heading) and aircraft weight which must be the major factors. Here's an incomplete list of aircraft that required gliding (from wiki).

An example of a prop-driven aircraft that had lost all power due to several errors is Tuninter Flight 1153, which was forced to ditch in the Mediterranean Sea after running out of fuel, was documented in an "Air Crash Investigations" episode. According to the investigation, they may have been able to glide to a nearby airport, but the pilots did not maintain the optimum glide speed for the aircraft type and did not feather the props in order to reduce drag on the aircraft. In gliding, potential energy in terms of altitude and speed is traded for distance. If energy is lost unnecessarily, the glide-distance is reduced accordingly.

But, to get back on topic, this was a powered jet with only one engine out, which is a completely different scenario. It may involve attempts to restart the failed engine (which may require an altitude change) and flying the aircraft with a single engine which is producing asymmetrical thrust on the aircraft. This means that the aircraft's has to be "flown" and will probably require flight control changes in order to maintain a correct attitude and control.

The famous example of a Boeing 747 that went out of control due to pilot inattention to aircraft attitude while troubleshooting a single engine failure is China Airlines Flight 006. The plane rolled and "plunged" (seems like a common term) 30,000 feet before the crew was able to pull it out of a high-speed, nearly fatal, dive. Handling a single engine failure on a four-engined 747 can probably be done routinely and with less drama that by a competent, trained and alert flight crew.

Did something similar to China Airlines 006 incident happen in this case?

Edited April 2, 2015 by MaxYakov