Emirates B777 gear collapse @ DXB?
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So, if:
Then it can't have been travelling much faster than 120kt ground speed (which is 3000m per minute, or 50m per second).
And if:
Then it has flown for nearly 1.5 minutes since it arrived over the landing threshold and presumably conducted a go-around (or windshear escape).
So, one can hardly surmise that the accident is due to slow engine spool-up or premature retraction of the landing gear.
Neither can one surmise that the thrust levers were not advanced as they couldn't possibly have flown for a further 90 seconds without thrust.
Now, if, as it seems:
Then the gear lever must have been selected UP less than 12 seconds prior to impact. Let's call it 10 seconds.
At 120 kts, 10 seconds is 500m. Suppose initial impact was 500m from runway end, the gear cannot possibly have been selected UP until 1000m prior to runway end. That is 3500m from the landing threshold. At least 60 seconds from the landing threshold.
If you had attempted a go-around (or windshear escape), and for a full 60 seconds of subsequent flight, your aircraft is still not climbing away (that would be a very long 60 seconds), is it possible the following would be going through your mind (as either PF or PM)?
"Aircraft not performing, have I done everything? TOGA? Thrust? Flap? Only gear to go, still waiting for positive rate! Waiting, waiting... ****, we have run out of runway! We'll crash if we don't do something. We can't get more thrust, what do we have left? Drag! Will getting rid of the drag save us? Can't think of anything else... Gear Up..."
Yes, I acknowledge that retracting flap is not part of a windshear escape, but we don't know whether they were performing a windshear escape yet. Perhaps flap retraction also only occurred as a subsequent attempt to save a non-performing aircraft.
Regardless, my main point is that is the little evidence available indicates that if indeed the gear was selected UP, it didn't happy early in the manoeuvre. It wasn't selected UP until seconds before impact. And it's conceivable that retracting the gear could have been a well-intended last-ditch effort to save an otherwise doomed aircraft.
- The aircraft was flying slowly enough to impact at tail-strike attitude (at least 10 degrees nose up)...
Then it can't have been travelling much faster than 120kt ground speed (which is 3000m per minute, or 50m per second).
And if:
- It impacted the ground near the far end of a 4500m runway...
Then it has flown for nearly 1.5 minutes since it arrived over the landing threshold and presumably conducted a go-around (or windshear escape).
So, one can hardly surmise that the accident is due to slow engine spool-up or premature retraction of the landing gear.
Neither can one surmise that the thrust levers were not advanced as they couldn't possibly have flown for a further 90 seconds without thrust.
Now, if, as it seems:
- It impacted the ground with landing gear "in transit"; and
- Full gear retraction takes approx 12 seconds...
Then the gear lever must have been selected UP less than 12 seconds prior to impact. Let's call it 10 seconds.
At 120 kts, 10 seconds is 500m. Suppose initial impact was 500m from runway end, the gear cannot possibly have been selected UP until 1000m prior to runway end. That is 3500m from the landing threshold. At least 60 seconds from the landing threshold.
If you had attempted a go-around (or windshear escape), and for a full 60 seconds of subsequent flight, your aircraft is still not climbing away (that would be a very long 60 seconds), is it possible the following would be going through your mind (as either PF or PM)?
"Aircraft not performing, have I done everything? TOGA? Thrust? Flap? Only gear to go, still waiting for positive rate! Waiting, waiting... ****, we have run out of runway! We'll crash if we don't do something. We can't get more thrust, what do we have left? Drag! Will getting rid of the drag save us? Can't think of anything else... Gear Up..."
Yes, I acknowledge that retracting flap is not part of a windshear escape, but we don't know whether they were performing a windshear escape yet. Perhaps flap retraction also only occurred as a subsequent attempt to save a non-performing aircraft.
Regardless, my main point is that is the little evidence available indicates that if indeed the gear was selected UP, it didn't happy early in the manoeuvre. It wasn't selected UP until seconds before impact. And it's conceivable that retracting the gear could have been a well-intended last-ditch effort to save an otherwise doomed aircraft.
The thing to remember about windshear escape maneuvers is that while the aircraft climb performance may be maximised, the energy loss might exceed the available performance.
Survivors can expect to be second guessed ad infinitum
Survivors can expect to be second guessed ad infinitum
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So, if:
And if:
So, one can hardly surmise that the accident is due to slow engine spool-up or premature retraction of the landing gear.
Neither can one surmise that the thrust levers were not advanced as they couldn't possibly have flown for a further 90 seconds without thrust.
Now, if, as it seems:
At 120 kts, 10 seconds is 500m. Suppose initial impact was 500m from runway end, the gear cannot possibly have been selected UP until 1000m prior to runway end. That is 3500m from the landing threshold. At least 60 seconds from the landing threshold.
If you had attempted a go-around (or windshear escape), and for a full 60 seconds of subsequent flight, your aircraft is still not climbing away (that would be a very long 60 seconds), is it possible the following would be going through your mind (as either PF or PM)?
"Aircraft not performing, have I done everything? TOGA? Thrust? Flap? Only gear to go, still waiting for positive rate! Waiting, waiting... ****, we have run out of runway! We'll crash if we don't do something. We can't get more thrust, what do we have left? Drag! Will getting rid of the drag save us? Can't think of anything else... Gear Up..."
Yes, I acknowledge that retracting flap is not part of a windshear escape, but we don't know whether they were performing a windshear escape yet. Perhaps flap retraction also only occurred as a subsequent attempt to save a non-performing aircraft.
Regardless, my main point is that is the little evidence available indicates that if indeed the gear was selected UP, it didn't happy early in the manoeuvre. It wasn't selected UP until seconds before impact. And it's conceivable that retracting the gear could have been a well-intended last-ditch effort to save an otherwise doomed aircraft.
- The aircraft was flying slowly enough to impact at tail-strike attitude (at least 10 degrees nose up)...
And if:
- It impacted the ground near the far end of a 4500m runway...
So, one can hardly surmise that the accident is due to slow engine spool-up or premature retraction of the landing gear.
Neither can one surmise that the thrust levers were not advanced as they couldn't possibly have flown for a further 90 seconds without thrust.
Now, if, as it seems:
- It impacted the ground with landing gear "in transit"; and
- Full gear retraction takes approx 12 seconds...
At 120 kts, 10 seconds is 500m. Suppose initial impact was 500m from runway end, the gear cannot possibly have been selected UP until 1000m prior to runway end. That is 3500m from the landing threshold. At least 60 seconds from the landing threshold.
If you had attempted a go-around (or windshear escape), and for a full 60 seconds of subsequent flight, your aircraft is still not climbing away (that would be a very long 60 seconds), is it possible the following would be going through your mind (as either PF or PM)?
"Aircraft not performing, have I done everything? TOGA? Thrust? Flap? Only gear to go, still waiting for positive rate! Waiting, waiting... ****, we have run out of runway! We'll crash if we don't do something. We can't get more thrust, what do we have left? Drag! Will getting rid of the drag save us? Can't think of anything else... Gear Up..."
Yes, I acknowledge that retracting flap is not part of a windshear escape, but we don't know whether they were performing a windshear escape yet. Perhaps flap retraction also only occurred as a subsequent attempt to save a non-performing aircraft.
Regardless, my main point is that is the little evidence available indicates that if indeed the gear was selected UP, it didn't happy early in the manoeuvre. It wasn't selected UP until seconds before impact. And it's conceivable that retracting the gear could have been a well-intended last-ditch effort to save an otherwise doomed aircraft.
hmmmm....just another theory my friend. CVR reading can resolve so many clues, what phase of flight and what part of SOP they failed to fly
I hope my ex EK coleagues will leak transcript soon. Thanks god all escaped even with bags...
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A question concerning a recent change to the missed approach procedures in Dubai UAE (OMDB) has raised some interesting points about the 777 in this flight regime: high thrust, low altitude, high pilot workload, and ATC procedures that would seem to be not too well thought out.
Specifically the new procedure introduces a not-above altitude of 1300 ft AMSL after going around from a near sea level Precision or GPS approach minimum (1000 ft missed approach climb).
This new procedure initially tracks straight ahead from the Missed Approach Point (MAP) (that’s a good thing) to DB710 – but requires the crew to level off at 1300 ft AMSL (Not so good). It then requires level flight for approximately 3nm (why? why?)
Low Missed Approach Altitude Restrictions | Flight
Specifically the new procedure introduces a not-above altitude of 1300 ft AMSL after going around from a near sea level Precision or GPS approach minimum (1000 ft missed approach climb).
This new procedure initially tracks straight ahead from the Missed Approach Point (MAP) (that’s a good thing) to DB710 – but requires the crew to level off at 1300 ft AMSL (Not so good). It then requires level flight for approximately 3nm (why? why?)
Low Missed Approach Altitude Restrictions | Flight
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I'm sure the crew would be well versed that the entire reason the gear isn't raised in a wind shear escape is as the gear doors open you have a lot more drag. The last thing I'd be thinking is raising the gear, if only to cushion the now inevitable impact.
Im sure the eventual report will be very interesting reading.
Im sure the eventual report will be very interesting reading.
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A question concerning a recent change to the missed approach procedures in Dubai UAE (OMDB) has raised some interesting points about the 777 in this flight regime: high thrust, low altitude, high pilot workload, and ATC procedures that would seem to be not too well thought out.
Specifically the new procedure introduces a not-above altitude of 1300 ft AMSL after going around from a near sea level Precision or GPS approach minimum (1000 ft missed approach climb).
This new procedure initially tracks straight ahead from the Missed Approach Point (MAP) (that’s a good thing) to DB710 – but requires the crew to level off at 1300 ft AMSL (Not so good). It then requires level flight for approximately 3nm (why? why?)
Low Missed Approach Altitude Restrictions | Flight
Specifically the new procedure introduces a not-above altitude of 1300 ft AMSL after going around from a near sea level Precision or GPS approach minimum (1000 ft missed approach climb).
This new procedure initially tracks straight ahead from the Missed Approach Point (MAP) (that’s a good thing) to DB710 – but requires the crew to level off at 1300 ft AMSL (Not so good). It then requires level flight for approximately 3nm (why? why?)
Low Missed Approach Altitude Restrictions | Flight
That's for 30L ......... doh!
Also, as said, notamed and removed quickly.
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I quote....
"hmmmm....just another theory my friend. CVR reading can resolve so many clues, what phase of flight and what part of SOP they failed to fly
I hope my ex EK coleagues will leak transcript soon. Thanks god all escaped even with bags".
Unqoute....
The spelling of "Co Workers" and the small "G" in "Alan the most beloved" is the give away there !
My experience ? Lived and worked in DXB ....and never again.
You can't even give "the finger" to some jumped up [email protected] for cutting you up on the road, fop fear said "[email protected]" is related to the cousin of the mother of the sister of the brother uncle of .....and so on.... and you get arrested (and that's happened !).
The "poster" prays for a leak !
And I pray that my dog starts sh*tting solid gold bricks.
Aint gonna happen.
I know it.
He knows it.
My dog knows it !
Dubai is Dubai. And that's not going to change. It's North Korea with ice cream.
Same dictatorship....but wearing Armani aftershave
"hmmmm....just another theory my friend. CVR reading can resolve so many clues, what phase of flight and what part of SOP they failed to fly
I hope my ex EK coleagues will leak transcript soon. Thanks god all escaped even with bags".
Unqoute....
The spelling of "Co Workers" and the small "G" in "Alan the most beloved" is the give away there !
My experience ? Lived and worked in DXB ....and never again.
You can't even give "the finger" to some jumped up [email protected] for cutting you up on the road, fop fear said "[email protected]" is related to the cousin of the mother of the sister of the brother uncle of .....and so on.... and you get arrested (and that's happened !).
The "poster" prays for a leak !
And I pray that my dog starts sh*tting solid gold bricks.
Aint gonna happen.
I know it.
He knows it.
My dog knows it !
Dubai is Dubai. And that's not going to change. It's North Korea with ice cream.
Same dictatorship....but wearing Armani aftershave
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Some minor numerical corrections:
Actually, 120 knots is a little over 60 meters per second, that two to one rule of thumb comes in handy when you fly to places like China with the wind speeds in meters.
Runway 12L at Dubai is 4300m long with 3600m usable past the displaced threshold and 3285m beyond the glide slope.
It impacted the ground near the far end of a 4500m runway...
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Not sure if already mentioned in previous posts, but could it be the same issue with the automation of the A/T that happened to Asiana in SFO?
No wake up of the A/T below 100ft RA during approach.... A/T mode in HOLD?
They pushed TOGA , called for FLAPS, rotated to 15 or so, but no thrust?
My 2 cents of thought.
No wake up of the A/T below 100ft RA during approach.... A/T mode in HOLD?
They pushed TOGA , called for FLAPS, rotated to 15 or so, but no thrust?
My 2 cents of thought.
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Yes, it should have been 3600m per minute, or 60m per second.
Point taken about the displaced threshold, thanks for that. Brings my 60 seconds down to 43. But still 43 long seconds.
Point taken about the displaced threshold, thanks for that. Brings my 60 seconds down to 43. But still 43 long seconds.
Last edited by Derfred; 8th Aug 2016 at 00:21.
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My experience ? Lived and worked in DXB ....and never again.
You can't even give "the finger" to some jumped up [email protected] for cutting you up on the road, fop fear said "[email protected]" is related to the cousin of the mother of the sister of the brother uncle of .....and so on.... and you get arrested (and that's happened !).
You can't even give "the finger" to some jumped up [email protected] for cutting you up on the road, fop fear said "[email protected]" is related to the cousin of the mother of the sister of the brother uncle of .....and so on.... and you get arrested (and that's happened !).
It impacted the ground near the far end of a 4500m runway...
It clearly impacted the ground some distance from where it came to a stop.
If 12 seconds for gear retraction is for the gear to retract normally, it is not necessarily valid in this case as it would have been assisted back into the gear bay by the weight of the aircraft settling onto it and must have been selected before impact as the over centre lock did not prevent retraction. I would disregard the 12 seconds between the up selection and impact. In fact the nose gear doors are still open in the pics.
Probably all happened a lot quicker.
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And now they're basing entire articles off us...!
Should overhead lockers be centrally locked? - BBC News
Should overhead lockers be centrally locked? - BBC News
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if figures are one to believe from FlightAware, speed 180kts was way too high at 600ft
https://flightaware.com/live/flight/.../OMDB/tracklog
Now, if, as it seems:
- It impacted the ground with landing gear "in transit"; and
- Full gear retraction takes approx 12 seconds...
It impacted the ground near the far end of a 4500m runway...
US Airways 1493 slid at least 300m/1000 feet after landing on a Metroliner at LAX. Admittedly gear down - but dragging (friction) the wreckage of the Metroliner under the fuselage. And was still sliding at a substantial speed when it hit an airport building and stopped abruptly. Conservatively, I think you need to assume "impact" was 300-500m prior to the final resting point.
Density altitude with 49°C temperature would make 120 on the gauge = about 130 TAS. But with a headwind, I'll accept 120 GS (and 10° pitch) as possible - at some point during the progression of the crash. Not convinced GS was as low as 120 kts at the beginning of the GA attempt.
Combine those with the actual available runway between the displaced thresholds, and I think your assumptions and math need revision.
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HiTech Nice one not!
Air Traffic controllers cannot close airports for weather. Pilot has total responsibility as to whether to make an approach. ATC can only give latest and best information to PIC.
Air Traffic controllers cannot close airports for weather. Pilot has total responsibility as to whether to make an approach. ATC can only give latest and best information to PIC.
I have worked. in a country were not only did ATC close the airport but also turned off the navaids..fun times.
Best one. Them "Airport closed because of weather"
Me. " I am at 15 miles and have visual with the runway!"
Them " Airport closed! You go away!"
Best one. Them "Airport closed because of weather"
Me. " I am at 15 miles and have visual with the runway!"
Them " Airport closed! You go away!"
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if figures are one to believe from FlightAware, speed 180kts was way too high at 600ft
Air Traffic controllers cannot close airports for weather.
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What I am confused by is how a light 777 on full thrust is struggling to climb. When heavy ones have no problem taking off. It did climb initially, seemingly, which precludes spool up time. Loss of power for some reason? Too much pitch up combined with increased tailwind? Did the a/c actually stall?
At least PAX and crew survived thankfully. It's a shame a firefighter lost his life in the call of duty.
