Emirates B-777 incident at DUBAI.

[silvercity]

This email was sent to me via a friend of an airline pilot mate of mine.

 

:

 

Subject: EMIRATES B777 CRASH LANDING

 

Aviation has a way of throwing up unexpected challenges. The case of the B777-300 crash in Dubai is in my opinion a case in point.

 

Let us examine the possibilities of why the event occurred to one of the world’s safest premier airlines in the world’s busiest international airport. As well Emirates pilots are trained to a very high level - practising emergency/abnormal procedures every 6 months in simulators. The B777 aircraft are probably the safest aircraft now flying.

 

Firstly Dubai airport on the Gulf coast - huge, modern and in 15 years of flying out of Dubai I never once encountered windshear ( which was a suggested reason for the aborted landing) There is no mountainous terrain nearby and thunderstorms are exceedingly rare. What I have encountered is gusty crosswinds around the landing crosswind limit of 35 knots.

 

Whatever reason the pilot decided to abort the landing it was the correct decision. However now comes certain factors that can catch an unwary pilot out.

 

When the B777-300 was introduced several years after the B777-200 it introduced new problems due to its extreme length of approximately 74 metres making it one of the longest aircraft in the world. It is easy to forget as a pilot that you have approximately 70 metres of hardware behind you.

 

New take procedures were introduced with a slower rotation rate on take-off and stopping at a deck angle of 12 degrees versus 15 degrees for the B777-200. Tail strikes have occurred on take-off by various airlines but that incidence is now very rare.

 

Go arounds - aborted landings - from a very low altitude are not common. Once on approach to land in London Heathrow airport following a landing Air Canada A340 the tower instructed me to expect a late landing clearance so I left the autopilot of the B777- 300 engaged. Suddenly a Canadian voice said " missed it we'll take the next one" ( missed the high speed runway exit taxiway ). Tower said " Emirates go round" so click TOGA switch on the thrust levers and from a wheel height of 50 feet above the runway the aircraft gracefully performed its automatic go around. Co-pilot called " positive climb " and I called for "gear up". Job done but that Canadian pilot cost Emirates 3 tons of extra fuel burnt as we re-joined the queue for landing.

 

When you have approximately 250 tons of aircraft descending on approach at 800 feet per minute there is a lot of momentum and height loss will occur after the decision to go around. The aircraft rotates about its centre of gravity which means initially as the pilots are rapidly ascending the tail is rapidly descending. I suggest the pilots felt they were climbing clear of the runway and retracted the gear just as the tail struck the runway causing the aircraft to crunch down on the runway..

 

This is only speculation but the gear was retracted and the pilots were performing a go around.

 

Interestingly when we were doing Category 111B auto land, in fog , in the Airbus with a wheel decision height of 15 feet ( CAT111C is 0 feet ) it was expected that the wheels might contact the runway on the go around from 15 feet. The much bigger B777-300 would have a bigger gravity drop.

 

This is one of the problems when you fly different models i.e. The B777-200 ( like MH370 and MH17 ) versus the much longer B777-300.

 

I am sure now all operators of B777-300 will introduce extra go around training for their pilots during their recurrent 6 monthly simulator training. A lesson for all pilots really. Just when you think everything is hunky-dory the Goddess of Gravity is just waiting to smite you.

 

Hard to classify the cause of this accident. I hope Emirates go soft on the pilots - it is easy to classify it as pilot error but it is in my opinion it is more of them being caught out in an unusual situation.

 

Emirates and Qantas still remain the world’s safest airlines with the best trained pilots. Never lost a passenger and Kudos to the excellent Cabin Staff that got everyone out safely - this being a testament to their training.

 

Accidents will always happen when humans are involved but flying is still the safest way to travel.

 

 

[Ozfergie]

Interesting article in the Oz today by veteran Captain Byron Bailey where he thinks a bounce was the start, followed by use of the TOGA switch on the throttle lever. His theory being that the first touchdown caused the flight computer to disable the auto-throttle because it "thought" they were on the ground and by the time the flight crew realised that the engines were not spooling up, it was too late for the manual override on the throttles to deliver enough thrust for the go around.

 

 

[dutchroll]

Another interesting facet I discussed with a colleague recently was the possibility of a mixup with the TOGA switches.

 

I remember coming from the B747 onto the B767 where the TOGA switches and autothrottle disconnect switches were in different positions which could cause confusion, leading to several inadvertent activations of go-around mode (ie full thrust and pitch up) in the simulator when all I wanted to do was disconnect the autothrottle and land!

 

I wonder if the scenario could be reversed. Wanted to activate go-around mode but disconnected the authothrottle instead? This could lead to a lot of confusion at a critical time.

 

 

[onetrack]

Haven't seen anyone mention the lag in spool-up time for the engines, either, once the throttles are shoved forward.

 

I've seen 6-7 seconds mentioned as the time before full thrust is available, after the throttle movement.

 

I'm guessing even 3 seconds lag would mean a lot, when you've either touched the runway, or you're only 15-20 feet off it.

 

 

[dutchroll]

Spool up time from flight idle to 95% takeoff thrust is 5 seconds or less. That's regulated by the FAA.

 

The engines remain in flight idle (a higher thrust than ground idle) for a period after touchdown to allow for this.

 

 

[facthunter]

That delay is related to P&W JT 8D jet engines and that is the maximum time above which the engine is considered unserviceable. It's from idle. Most other engines aren't quite as bad. If above idle the response is much better. including the situation where they are spooling down to idle. For safety you spool up slightly, below 3,000 altitude when descending. 7 seconds is a long time when you need it, and it's something you allow for. Virtually no approach has power at idle till you flare, or just before. Heavy and into strong headwinds the power is quite high on the normal sloped approach. Sometimes above 80%. Bit different to a Drifter. Nev

 

 

[facthunter]

Perhaps it should be" safe height and established a positive climb"?. I would never act on the needles (IVSI) first movement unless a near obstacle climb limit applies and engine power loss. In most planes there is more drag retracting than gear down, due landing gear doors. With 2 engines operating full power (only used on critical take offs) on these kinds of aircraft, you are really overpowered and will fly rapidly through any low level you are assigned to if you don't watch things. Certainly zero gravity will impress the Pax NOT. Nev

 

 

[dutchroll]

Perhaps it should be" safe height and established a positive climb"?.

The only problem is creating a hard and meaningful definition of "safe height" which is not open to interpretation - bearing in mind that the gear needs to come up fairly quickly after a takeoff or go-around for performance reasons.

It's a generally accepted rule that once the radar altitude and altimeter are increasing, the height is safe given that you're already supposed to be established in the manoeuvre (full thrust and pitching to around 15 degrees nose up).

 

 

[facthunter]

Safe Height is when there is no chance of sinking back onto the runway. If there is any doubt make it no doubt and wait. On two motors you have $hitloads of power. If the tail hits first you pitch down and it's all over if the gear is retracted. Nev

 

 

[dutchroll]

I guess what I'm saying is that 6 inches would be a safe height under normal circumstances. With a speed above Vr (rotate speed for the uninitiated) and TOGA (takeoff/go around thrust setting, or basically flat strap for the uninitiated) and 15 degrees nose up, there's no chance of settling back onto the runway in any of these modern jets today. They all have so much excess power.

 

To settle back onto the runway, you have to screw something up (as likely happened) or get a very sudden and incredibly severe windshear. All that's needed is to establish that you are in fact climbing, hence the "positive climb" call.

 

 

[facthunter]

You still have to reconfigure the flap. Done wrong that won't help things, either by having too much or it going too far in to retract and any fault with your auto thrust becomes critical. Nev

 

 

[fly_tornado]

 

 

 

 

[Bats]

Just as well nobody thought sitting tight in a burning aircraft was a good idea this time around; that's pretty well toasted.

 

 

[onetrack]

Gee, those crane operators are pretty careless! Don't they understand you can seriously damage an aircraft by slinging chains around it??

 

 

[Marty_d]

That wing looks ok... pop out a few rivets, buff out the burn marks on the engine cowling... she'll be right!

 

 

[Bats]

Interesting that there seems to be a set of dunlops dangling more or less as nature intended - at least on one side. I guess they may have still been in transit when she dropped back on the runway or otherwise the fire damage was sufficient to disrupt the uplock mechanism.

 

 

[facthunter]

If they don't get caught by the uplocks, in the full "UP" position they will free fall (most of the way, if not all) without hydraulics holding them up. From what I can see that looks to be fully down. Nev

 

 

[bexrbetter]

Emirates B777 crash was accident waiting to happen

 

• BYRON BAILEY
   
   
  
• The Australian
   
   
  
• 12:00AM August 9, 2016
   
   
  
• Save
   
   
  
•  
  Share on Facebook
   
   
  
• Share on Twitter
   
   
  
• Share on email
   
   
  
• Share more...
   
   
  

 

 

[*]113

 

The crash of an Emirates B777 during an attempted go-around in Dubai last Wednesday was always an accident waiting to happen.

 

It was not the fault of the pilots, the airline or Boeing, because this accident could have happened to any pilot in any airline flying any modern glass cockpit airliner — Airbus, Boeing or Bombardier — or a large corporate jet with autothrottle.

 

It is the result of the imperfect interaction of the pilots with supposedly failsafe automatics, which pilots are rigorously trained to trust, which in this case failed them.

 

First, let us be clear about the effect of hot weather on the day. All twin-engine jet aircraft are certified at maximum takeoff weight to climb away on one engine after engine failure on takeoff at the maximum flight envelope operating temperature — 50 degrees C in the case of a B777 — to reach a regulatory climb gradient minimum of 2.4 per cent.

 

The Emirates B777-300 was operating on two engines and at a lower landing weight, so climb performance should not have been a problem. I have operated for years out of Dubai in summer, where the temperature is often in the high 40s, in both widebody Airbus and Boeing B777 aircraft.

 

Secondly, a pilot colleague observed exactly what happened as he was there, waiting in his aircraft to cross runway 12L. The B777 bounced and began a go-around. The aircraft reached about 150 feet (45 metres) with its landing gear retracting, then began to sink to the runway.

 

This suggests that the pilots had initiated a go-around as they had been trained to do and had practised hundreds of times in simulators, but the engines failed to respond in time to the pilot-commanded thrust. Why?

 

Bounces are not uncommon. They happen to all pilots occasionally. What was different with the Emirates B777 bounce was that the pilot elected to go around. This should not have been a problem as pilots are trained to apply power, pitch up (raise the nose) and climb away. However pilots are not really trained for go-arounds after a bounce; we practise go-arounds from a low approach attitude.

 

Modern jets have autothrottles as part of the autoflight system. They have small TOGA (take off/go-around) switches on the throttle levers they click to command autothrottles to control the engines, to deliver the required thrust. Pilots do not physically push up the levers by themselves but trust the autothrottles to do that, although it is common to rest your hand on the top of the levers. So, on a go-around, all the pilot does is click the TOGA switches, pull back on the control column to raise the nose and — when the other pilot, after observing positive climb, announces it — calls “gear up” and away we go!

 

But in the Dubai case, because the wheels had touched the runway, the landing gear sensors told the autoflight system computers that the aircraft was landed. So when the pilot clicked TOGA, the computers — without him initially realising it — inhibited TOGA as part of their design protocols and refused to spool up the engines as the pilot commanded.

 

Imagine the situation. One pilot, exactly as he has been trained, clicks TOGA and concentrates momentarily on his pilot’s flying display (PFD) to raise the nose of the aircraft to the required go-around attitude — not realising his command for TOGA thrust has been ignored. The other pilot is concentrating on his PFD altimeter to confirm that the aircraft is climbing due to the aircraft momentum. Both suddenly realise the engines are still at idle, as they had been since the autothrottles retarded them at approximately 30 feet during the landing flare. There is a shock of realisation and frantic manual pushing of levers to override the autothrottle pressure.

 

But too late. The big engines take seconds to deliver the required thrust before and before that is achieved the aircraft sinks to the runway.

 

It could have happened to any pilot caught out by an unusual, time-critical event, for which rigorous simulator training had not prepared him.

 

Automation problems leading to pilot confusion are not uncommon; but the designers of the autoflight system protocols should have anticipated this one. Perhaps an audible warning like “manual override required” to alert the pilots immediately of the “automation disconnect”.

 

My feeling is the pilots were deceived initially by the autothrottle refusal to spool up the engines, due to the landing inhibits, and a very high standard of simulator training by which pilots are almost brainwashed to totally rely on the automatics as the correct thing.

 

 

[onetrack]

There's no sign of the MLG being extended in any previous photos I've seen - those taken right about evac time. If "gear up" had been selected, wouldn't the gear have cycled right through, until the uplocks engaged?

 

It looks to me like the gear fell down when the hull was lifted - leading one to presume the gear was partially cycled up, but the uplocks hadn't engaged.

 

What I find interesting, is the relatively little signs of hull and engine pod scarring on the underside - which I thought would have been pretty substantial, when you have 250 tonnes skating on its belly (well, on engine pods initially, then belly), starting at somewhere around 150 kts, and continuing for perhaps 1200-1500 feet? I would have expected some pretty major scars.

 

It certainly looks like Boeing build 'em tough alright - I reckon a few other Brand X's would have broken the fuselage in at least a couple of places.

 

 

[facthunter]

I think the right side engine detached and the plane was leaning that way probably with most of the weight on the belly by that time .I think it swung/slewed to the right as it stopped. nev

 

 

[WayneL]

The following copy was sent to me recently, maybe Dutchroll can comment on the content.

 

Wayne.

 

Piece copied from “The Australian”, authored by Byron bailey.

 

 

How flight computers misled pilots

 

Emirates B777 crash was accident waiting to happen

 

The crash of an Emirates B777 during an attempted go-around in Dubai last Wednesday was always an accident waiting to happen.

 

It was not the fault of the pilots, the airline or Boeing, because this accident could have happened to any pilot in any airline flying any modern glass cockpit airliner — Airbus, Boeing or Bombardier — or a large corporate jet with autothrottle.

 

It is the result of the imperfect interaction of the pilots with supposedly failsafe automatics, which pilots are rigorously trained to trust, which in this case failed them.

 

First, let us be clear about the effect of hot weather on the day. All twin-engine jet aircraft are certified at maximum takeoff weight to climb away on one engine after engine failure on takeoff at the maximum flight envelope operating temperature — 50 degrees C in the case of a B777 — to reach a regulatory climb gradient minimum of 2.4 per cent.

 

The Emirates B777-300 was operating on two engines and at a lower landing weight, so climb performance should not have been a problem. I have operated for years out of Dubai in summer, where the temperature is often in the high 40s, in both widebody Airbus and Boeing B777 aircraft.

 

Secondly, a pilot colleague observed exactly what happened as he was there, waiting in his aircraft to cross runway 12L. The B777 bounced and began a go-around. The aircraft reached about 150 feet (45 metres) with its landing gear retracting, then began to sink to the runway.

 

This suggests that the pilots had initiated a go-around as they had been trained to do and had practised hundreds of times in simulators, but the engines failed to respond in time to the pilot-commanded thrust. Why?

 

Bounces are not uncommon. They happen to all pilots occasionally. What was different with the Emirates B777 bounce was that the pilot elected to go around. This should not have been a problem as pilots are trained to apply power, pitch up (raise the nose) and climb away. However pilots are not really trained for go-arounds after a bounce; we practise go-arounds from a low approach attitude.

 

Modern jets have autothrottles as part of the autoflight system. They have small TOGA (take off/go-around) switches on the throttle levers they click to command autothrottles to control the engines, to deliver the required thrust. Pilots do not physically push up the levers by themselves but trust the autothrottles to do that, although it is common to rest your hand on the top of the levers. So, on a go-around, all the pilot does is click the TOGA switches, pull back on the control column to raise the nose and — when the other pilot, after observing positive climb, announces it — calls “gear up” and away we go!

 

But in the Dubai case, because the wheels had touched the runway, the landing gear sensors told the autoflight system computers that the aircraft was landed. So when the pilot clicked TOGA, the computers — without him initially realising it — inhibited TOGA as part of their design protocols and refused to spool up the engines as the pilot commanded.

 

Imagine the situation. One pilot, exactly as he has been trained, clicks TOGA and concentrates momentarily on his pilot’s flying display (PFD) to raise the nose of the aircraft to the required go-around attitude — not realising his command for TOGA thrust has been ignored. The other pilot is concentrating on his PFD altimeter to confirm that the aircraft is climbing due to the aircraft momentum. Both suddenly realise the engines are still at idle, as they had been since the autothrottles retarded them at approximately 30 feet during the landing flare. There is a shock of realisation and frantic manual pushing of levers to override the autothrottle pressure.

 

But too late. The big engines take seconds to deliver the required thrust before and before that is achieved the aircraft sinks to the runway.

 

It could have happened to any pilot caught out by an unusual, time-critical event, for which rigorous simulator training had not prepared him.

 

Automation problems leading to pilot confusion are not uncommon; but the designers of the autoflight system protocols should have anticipated this one. Perhaps an audible warning like “manual override required” to alert the pilots immediately of the “automation disconnect”.

 

My feeling is the pilots were deceived initially by the autothrottle refusal to spool up the engines, due to the landing inhibits, and a very high standard of simulator training by which pilots are almost brainwashed to totally rely on the automatics as the correct thing.

 

Byron Bailey is a commercial pilot with more than 45 years’ experience and 26,000 flying hours, and a former RAAF fighter pilot. He was a senior captain with Emirates for 15 years.

 

 

[SDQDI]

I'm not an expert on big planes so I won't enter into a discussion on the maybes or maybe nots of this particular case but I Would like to point out one thing said by Mr Bailey.

 

"Pilots are not really trained for go arounds a after a bounce,"

 

It was my experience in my training that I did a lot more go arounds after bounces than I did low level aborted landings! Maybe that says bad things about my landings but in my case it was true. Learning in the J3 cub I got very proficient at bouncing the first attempt then with just the right amount of power recovering the balloon and greasing the second landing:whistling:

 

 

[WayneL]

Sorry Bex, I did not see your post before I posted the same letter.

 

Wayne.

 

 

[Bennyboy320]

"Pilots are not really trained for go arounds a after a bounce,"

Yes we are, my company is doing this an an exercise on our day 2 sim session of our current PC.

 

Makes me feel confident that on the Bus you will get the thrust that you demand, i.e. manually push the thrust levers all the way to the firewall & you get TOGA thrust.

 

 

[facthunter]

SDQDI. There is a marked difference between a Cub and a large jet re "bouncing". The Piper will pitch up from a mainwheels contact with a fair ROD. A tri gear jet will tend to pitch down,(same as any tri gear). Also there is no damping on a basic U/C on an ultralight, so whatever energy the spring(s) absorb they give back. The gear on a big jet is well damped and doesn't tend to throw the plane back into the air.

 

Also once the ground spoilers have extended, most of the lift has GONE, whereas on a small plane you still have enough to fly. As I said in a previous post, I've never seen a Passenger jet "bounce " in the general sense, from inside or outside the cockpit. IF the spoilers aren't activated either manually or automatically you can "skip" for a looong way, distance wise if not height wise and waste a lot of runway and have trouble stopping with the distance remaining after your "second" landing. Most times you don't have "tons" of runway to spare, so landing "long" (coming in high or fast), or skipping (bouncing) is not encouraged. You have the wheels on the ground and spoilers activated and brakes available (weight on wheels) as soon as possible. Nev