Artc
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Last Year B777 Missed Landing

Sun May 06, 2012 2:32 am

I was watching some videos and came across with one that got the moment in which a Singapore Airlines B777 skids off the runway on landing. It happened last November.
It seems that the crew performed an autoland without advising ATC and another aircraft blocked the localizer signal or something. Fortunately nobody was seriously injured.
I hope it is not a repost.

Good day.
artur

http://www.youtube.com/watch?v=0rn-iI7wX-Y

[Edited 2012-05-05 19:33:43]
 
AT
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 2:38 am

Bizarre. When did this happen?

Also note that no thrust reversers were deployed... I wonder why.
 
Viscount724
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 2:46 am

Aerial photo showing its excursion, first to the left and then to the right.

http://dannews.co.nz/wp-content/uploads/2012/02/sq_landing.jpg

[Edited 2012-05-05 19:55:38]
 
Viscount724
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 2:52 am

Quoting at (Reply 1):
Bizarre. When did this happen?

November 3, 2011.
http://www.flightglobal.com/airspace...v-swq-slides-off-munich-79867.aspx

I was on a KLM 737-700 from AMS to MUC that evening after the runway reopened, but there was a big backlog of delayed and diverted flights since one of the two runways had been closed most of the day. The KL flight I was on didn't have enough fuel to hold very long so we diverted to NUE for more fuel and finally arrived MUC about 2 hours late.
 
PHX787
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 3:23 am

Looks like the nose bounced up and down quite a bit
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as739x
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 3:28 am

I've never encountered the crew having to notify ATC they were doing an Autoland. If IFR conditions persist, then a/c are to stay out of the IFR save boundary.
"Some pilots avoid storm cells and some play connect the dots!"
 
redrooster3
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 5:18 am

How do they get the aircraft out of there? With it's own power? Or a tow truck.
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spacecadet
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 5:33 am

Quoting at (Reply 1):
Also note that no thrust reversers were deployed... I wonder why.

Appears they might have tried to take off again, but were already stuck in the mud.
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777222LR
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 6:17 am

Quoting PHX787 (Reply 4):

Looks like the nose bounced up and down quite a bit

Didn't bounce, they tried to take off again, hence the reason no reverse thrust was selected.
 
AR385
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 6:28 am

Quoting redrooster3 (Reply 6):
How do they get the aircraft out of there? With it's own power? Or a tow truck.

In most cases, it´s a nightmare. It requires jacks, airbags, or both. And then it is usually towed. In this case, though, the plane taxied back onto the runway on its own power without the passengers. It really depends on wether or not the gear gets stuck and how deep.
 
sandyb123
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 7:26 am

Quoting at (Reply 1):
Also note that no thrust reversers were deployed... I wonder why.

I noticed that, I at first though the black spray was carbon from the brakes, but from the ariel view looks like there was an over correction with stabiliser / nose gear / thrust.

Quoting spacecadet (Reply 7):
Appears they might have tried to take off again, but were already stuck in the mud.

I doubt that, if the TO/GA command had been issued the flaps would have retracted to a take off configuration.

Given the way the nose bounced back down, a take off attempt may have resulted in an aerodynamic stall?

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IanatSTN
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 7:34 am

Quoting as739x (Reply 5):
I've never encountered the crew having to notify ATC they were doing an Autoland. If IFR conditions persist, then a/c are to stay out of the IFR save boundary.

In my company, Low Visibility Procedures must be in force in order to conduct a Cat II/III approach. If they are not then you cannot garentee the ILS protected area is clear of obstacles/other aircraft etc. Just because its cloudy doesnt mean that LVPs are in use, certain weather minima are usually have to be breached.
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flyingzacko
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 7:39 am

Quoting IanatSTN (Reply 11):
In my company, Low Visibility Procedures must be in force in order to conduct a Cat II/III approach. If they are not then you cannot garentee the ILS protected area is clear of obstacles/other aircraft etc. Just because its cloudy doesnt mean that LVPs are in use, certain weather minima are usually have to be breached.

It is the same way at my company. LVP have to be in force from the airport's side before performing any CAT II/III approach. And then, aircraft would be advised to hold short of the CAT II/III stopbars before the runway, so the sensitive area remains clear.
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AR385
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 7:56 am

The GBA reported that on approach the crew decided to perform a fully automatic landing onto runway 08R when the weather conditions were below the limits that permitted the the first officer, pilot flying to do the landing.

The captain became pilot flying, the first officer became pilot monitoring. The airport was operating according to CAT I standards.

At 2 nm before touch down a regional jet began its takeoff run on runway 08R. Winds were from 130 degrees at 7 knots. When the SQ flight crossed the runway threshold, the regional jet was climbing out short of the runway end.
At the time of touchdown of the SQ flight the regional jet was climbing out past the runway end.

When the SQ flight reached 30 feet AGL, the aircraft began to roll left, landed, and the autopilot changed into roll out mode. The aircraft kept moving towards the left edge of the runway and crossed it. Rudder inputs by the PF disengaged the autopilot

The aircraft then rolled in a slight right turn over grass for about 400 meters, before it crossed the runway edge again onto the runway and crossed the runway reaching the right runway edge and exiting said runway.. The aircraft came to a stop on grass off the runway.

The GBA says the captain tried to go-around when the aircraft began to roll left. He pressed the TOGA button, but the aircraft did not respond. He then retracted the spoilers that had automatically extended. Strange, because it does not seem in the video that the spoilers ever activated.

The GBA reports the aircraft began to roll left in response to autopilot inputs to minimize the localizer deviation and reached 3.5 degrees bank angle to the left when the autopilot changed to roll out.

Very contradictory to the captain´s statements is the fact that there were no indications of the TOGA button pushed on the FDR.

So. Not my intention to second guess this crew´s landing attempt but it does not seem that there was an autopilot/ILS issue per se.
 
awthompson
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 8:40 am

It is great that someone was filming in those dull conditions. Does anything get missed nowadays!

Thats the first time I have ever seen/heard (on video) a Boeing 777-300 skidding sideways on tarmac/grass!

Co-incidentally, I was just watching 9V-SWQ on radar departing Manchester just before I clicked on this video! And what's more, he is on the way to Munich right now!
 
BA777
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 9:56 am

We dont know the whole story, but perhaps a rushed approach and late change between PF and PNF roles? Surely if in any doubt, disconnect and fly the plane manually and go around if necessary and come in again.
 
GearDownFlaps30
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 11:44 am

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EK413
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 11:58 am

Quoting spacecadet (Reply 7):

I'll say an aborted landing the result could've been worse...

EK413
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GearDownFlaps30
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 12:22 pm

Joking aside, this must have been a terribly freaking experience for everybody onboard, seeing your plane skidding from left to right, not knowing how it's gonna end. It's not like a car you can (try) countersteer when it skids... I guess when it was clear the crew couldn't TOGA they understood they "just" had to wait the the drama to come to an end.
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bueb0g
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 12:34 pm

Quoting sandyb123 (Reply 10):
I doubt that, if the TO/GA command had been issued the flaps would have retracted to a take off configuration.

The captain did actually press the TOGA buttons but the aircraft didn't respond to the command.
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as739x
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 3:34 pm

Quoting IanatSTN (Reply 11):
Quoting flyingzacko (Reply 12):

Good to know. Thanks
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Kaiarahi
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 4:03 pm

If anyone is interested in the facts, rather than speculating, the initial report (factual, no analysis yet) from the German Bundesstelle für Flugunfalluntersuchung is here: http://www.bfu-web.de/cln_030/nn_226...tualReport_11_EX010_B777_Munic.pdf

Quoting AR385 (Reply 13):
Very contradictory to the captain´s statements is the fact that there were no indications of the TOGA button pushed on the FDR.

The FDR readout indicates TOGA was selected.
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boacvc10
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 4:46 pm

In the report it is mentioned emergency responders took 2 minutes to arrive on the scene (?).

I think the amateur video shows a somewhat faster response, right?

Also, where emergency slides not deployed for any reason? The flight deck would not have known of any damage to the engines/fuel supply at that point ...

Quoting Kaiarahi (Reply 21):
If anyone is interested in the facts, rather than speculating,
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AirlineCritic
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 5:56 pm

Quoting Kaiarahi (Reply 21):
If anyone is interested in the facts, rather than speculating, the initial report (factual, no analysis yet) from the German Bundesstelle für Flugunfalluntersuchung is here

Thank you!

Quoting Kaiarahi (Reply 21):
The FDR readout indicates TOGA was selected.

But it does not! The FDR says nothing TOGA related was going on, CVR however does indicate sounds similar to pressing TOGA. A quote from the report:

Quote:
The FDR did not show any indications for the initiation of a go-around procedure. However, the Cockpit Voice Recorder (CVR) recorded at the time of the touch down the PIC's command "ok, flaps 20" together with several sounds which indicate the clicking of the TOGA lever and the movement of the speedbrake handle.

Another interesting part of the report is that the autopilot apparently made the initial bank and turn:

Quote:
The airplane began to roll to the left and at 11:09:16 UTC reached a maximum bank angle of 3.5° when it touched down with its left main landing gear. At the time the autopilot was still engaged; the approach mode changed into rollout mode. Because the autopilot generated control inputs to minimise the lateral beam deviation the airplane turned left

Can the experts on this forum tell me why this could potentially be the case? Are there external factors that could lead into this? Could the pilots have caused this? Or is this an autopilot malfunction?

Finally, why is the report focusing on the other aircraft leaving the runway? Is tehre some possibility that it has distracted either the autopilot, the regular pilots, or some navigational aids?
 
Pihero
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 6:57 pm

Quoting AirlineCritic (Reply 23):
Another interesting part of the report is that the autopilot apparently made the initial bank and turn:

Yes, they were executing an automatic landing : "During the approach briefing the crew had decided to perform an automatic approach and landing".
...and the aircraft was under A/P control.

Quoting AirlineCritic (Reply 23):
why is the report focusing on the other aircraft leaving the runway? Is there some possibility that it has distracted either the autopilot, the regular pilots, or some navigational aids?

Any metallic obstacle on or close to the axis of the localiser beamcould warp it, that's why it is important to know whether the AVRO did, in fact disturb the localiser antennas' pattern. Apparently not as it was on the other side of the Loc when the T7 landed.(That's why Cat 2 and 3 protections make sure that holding airplanes are nowhere close to the runway during LVP )

There are a few questions to be asked on this incident :
1/- Where came the Loc signal disturbance from ?
2/- It seems to me that the switch over to the "Roll out" mode from the "Approach" mode was a bit quick : what are the required conditions : only one gear contact doesn't sound right to me.
3/- The DFDR doesn't show any"Go Around" selection, but the Captain said it did and the CVR recorded the call for a reduced flap setting (part of the manoeuvre ). So what in reality did happen ?
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rfields5421
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 7:13 pm

Quoting AR385 (Reply 13):
When the SQ flight crossed the runway threshold, the regional jet was climbing out short of the runway end.
At the time of touchdown of the SQ flight the regional jet was climbing out past the runway end.

So the locaizer interference was from a departing aircraft, not from an aircraft crossing the CATII/III hold lines?

Quoting boacvc10 (Reply 22):
I think the amateur video shows a somewhat faster response, right?

There is at least a 20-30 second break in the video between the last aircraft movement on the video and filming when the aircraft is stopped. The camera moves quite a distance. Probably the reason we don't see the aircraft finally stopping is an obstruction and the camera was moved to get a good view of the aircraft.

On the video the AARF arrives about 1:35 - so 2 minutes for arrival at the aircraft works out about right.
 
PanAm1971
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 8:02 pm

That is some tough landing gear! Is this possibly a symptom of over reliance on autoland?
 
sandyb123
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 8:15 pm

Having now read the report in full, I have a few questions...

Quoting Pihero (Reply 24):
3/- The DFDR doesn't show any"Go Around" selection, but the Captain said it did and the CVR recorded the call for a reduced flap setting (part of the manoeuvre ). So what in reality did happen ?

This information is contradictory, the captain with PIC and PF so who was he telling in the CVR? It would have been his task? Regardless the button wasn't pushed and the overspeed on the steering input is what disengaged the A/P.

Quoting Pihero (Reply 24):
2/- It seems to me that the switch over to the "Roll out" mode from the "Approach" mode was a bit quick : what are the required conditions : only one gear contact doesn't sound right to me.

This reminds me of the famous AF296 crash back in 1988 when the plane made the decision that it had landed when it hadn't. Although the TOGA button wasn't pushed so this might not have been contributory.

Quoting AirlineCritic (Reply 23):
Another interesting part of the report is that the autopilot apparently made the initial bank and turn:

More interestingly is that at the start of the bank left the aircraft was only 30ft AGL. Why didn't the Captain react immediately to the fact his aircraft was veering off-course at a critical stage of flight with either the TOGA or a rudder input (which would have automatically handed the plane back to him).

All I can say is thank god there wasn't an aircraft holding in the taxiways B4 or B6.

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zkojq
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 10:00 pm

Its actually quite frightening to see such a large, powerful aircraft skidding down the runway, out of control.

According to the BFU report, the co-pilot:

Quote:

Total flying experience: 3,681 hours
Flying experience
on the type: 3,681 hours

That seems rather odd. Surely he would have done some flying in aircraft other than B777s?  
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Pihero
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 10:02 pm

Quoting sandyb123 (Reply 27):
This information is contradictory, the captain with PIC and PF so who was he telling in the CVR? It would have been his task?
Quoting sandyb123 (Reply 27):
Regardless the button wasn't pushed and the overspeed on the steering input is what disengaged the A/P.

Not quite, the report specifically says : "However, the Cockpit Voice Recorder (CVR) recorded at the time of the touch down the PIC's command "ok, flaps 20" together with several sounds which indicate the clicking of the TOGA lever and the movement of the speedbrake handle."
These are consistent with the drill " TOGA / Flaps... make sure speedbrakes stowed... announce FMA (which they never did ). On the other hand, those TOGA switches are not my favourite way of ensuring the go-around trigger.

"the PIC with 23 lbs and the co-pilot with 41 lbs - and over-steered the autopilot which disengaged immediately afterwards."
Please note that here we have an example of a dual flight control input with an over-correction of the left deviation.
Could be the main reason for the runway exit.
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flylku
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 10:09 pm

Quoting PanAm1971 (Reply 26):
That is some tough landing gear!

My initial thought also. I'm sure Boeing never flew the 777 in and out of grass strips during the certification process. Actually, it is the transitions from pavement to runway and back that would concern me the most.
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tp1040
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 10:13 pm

What kind of damage would the plane have.? I would imagine a lot of stress on the landing gear.
 
flightsimer
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RE: Last Year B777 Missed Landing

Sun May 06, 2012 11:43 pm

Quoting sandyb123 (Reply 27):
More interestingly is that at the start of the bank left the aircraft was only 30ft AGL. Why didn't the Captain react immediately to the fact his aircraft was veering off-course at a critical stage of flight with either the TOGA or a rudder input (which would have automatically handed the plane back to him

It was only 3.5 degrees at the max. At 30ft it was only another 3-4 sec until touchdown. The roll happened so slow and shallow that he probably figured it would right itself or was temporaraly occurring due to a natural force (what were winds like). Also he would not have corrected with rudder while in the air and there is a disconnect button right at his finger's reach on the yoke that he could have hit if he felt it needed to be.

The issue wasn't really until when the left main was on the ground and the turning force was still being applied. Because of that the right main came down 5 seconds later when assumingably the pilot hit the rudders to correct. To me it looks like the plane doesnt even reach the full 3.5 degrees until the left main is firmly on the ground.

Luckily, it appears that for the most part, the weight of the aircraft was on the mains almost the entire time during the initial skid and when the aircraft re-entered the runway.
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tdscanuck
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RE: Last Year B777 Missed Landing

Mon May 07, 2012 12:56 am

Quoting AirlineCritic (Reply 23):
Quote:
The airplane began to roll to the left and at 11:09:16 UTC reached a maximum bank angle of 3.5° when it touched down with its left main landing gear. At the time the autopilot was still engaged; the approach mode changed into rollout mode. Because the autopilot generated control inputs to minimise the lateral beam deviation the airplane turned left

Can the experts on this forum tell me why this could potentially be the case? Are there external factors that could lead into this? Could the pilots have caused this? Or is this an autopilot malfunction?

This is the normal autopilot response to being right of the localizer beam (presumably because the localizer beam bent to the left). In the air, the airplane would bank to try to center on the beam. On the ground it would steer left to try to get to the beam. In both cases the autopilot believes the localizer beam is the center of the runway (since that's the entire purpose of a localizer).

Quoting Pihero (Reply 24):
2/- It seems to me that the switch over to the "Roll out" mode from the "Approach" mode was a bit quick : what are the required conditions : only one gear contact doesn't sound right to me.

You can't switch from "Approach" to "Rollout" mode. ROLLOUT is a heading control mode. The equivalent mode in the air is LOC, not APPROACH (the altitude mode would switch from G/S to FLARE). There is no FMA annunciation of "APPROACH" on a 777.

Quoting sandyb123 (Reply 27):
More interestingly is that at the start of the bank left the aircraft was only 30ft AGL. Why didn't the Captain react immediately to the fact his aircraft was veering off-course at a critical stage of flight with either the TOGA or a rudder input (which would have automatically handed the plane back to him).

It's a 3.5 degree slow bank...that's nothing to be alarmed about in that situation.

Tom.
 
Viscount724
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RE: Last Year B777 Missed Landing

Mon May 07, 2012 1:48 am

Quoting AR385 (Reply 9):
Quoting redrooster3 (Reply 6):
How do they get the aircraft out of there? With it's own power? Or a tow truck.

In most cases, it´s a nightmare. It requires jacks, airbags, or both. And then it is usually towed. In this case, though, the plane taxied back onto the runway on its own power without the passengers. It really depends on wether or not the gear gets stuck and how deep.

The ground was very firm. Based on photos the wheels barely sunk into the grass.

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Kaiarahi
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RE: Last Year B777 Missed Landing

Mon May 07, 2012 12:05 pm

Quoting AirlineCritic (Reply 23):
But it does not! The FDR says nothing TOGA related was going on, CVR however does indicate sounds similar to pressing TOGA.
Quoting Pihero (Reply 24):
The DFDR doesn't show any"Go Around" selection

My mistake - reading too quickly! I was looking at the CVR printout.
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N14AZ
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RE: Last Year B777 Missed Landing

Mon May 07, 2012 12:12 pm

Quoting Viscount724 (Reply 34):
The ground was very firm.

I remember the time last year when this incident happened. We didn't have any rains in November for some days (even weeks). You can see this from the colour of the gras (well, if you know how it usually looks in Munich in November). Therefore I always wondered what would have happened if the ground would have been wet as usual during that time of the year. Maybe the nose or parts of the main landing gear would have been damaged when going back onto the runway.
 
sandyb123
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RE: Last Year B777 Missed Landing

Mon May 07, 2012 4:15 pm

I am no commercial pilot, let alone a wide body pilot. My aircraft would fit through the door of a 777  , but....

Quoting tdscanuck (Reply 33):
It's a 3.5 degree slow bank...that's nothing to be alarmed about in that situation.
Quoting flightsimer (Reply 32):
It was only 3.5 degrees at the max. At 30ft it was only another 3-4 sec until touchdown.

Even at 3.5% bank angle the aircraft will start to make a noticeable change in direction towards the runway threshold. 4 seconds equates to approx. 280 meters at 160 ktas (approach speed). A reaction from the captain within this timeframe (rudder, TOGA, something else) may have avoided the excursion.

Quoting flightsimer (Reply 32):
Also he would not have corrected with rudder while in the air and there is a disconnect button right at his finger's reach on the yoke that he could have hit if he felt it needed to be.

I think this is an example of over-reliance on automation. The rudder is used every day on cross wind landings or to kick out any changes in the final stages of flight. IIRC the autopilot has no rudder authority and wouldn't have used it in any case as logically (it's logic) there was nothing wrong. I propose that the thing to do would be to disengage the A/P and correct / go around.

Quoting Pihero (Reply 29):
Please note that here we have an example of a dual flight control input with an over-correction of the left deviation.

This reminds me of AF477, although at least the inputs were consistent rather than contradictory. Regardless, surely the FO should not have made the input?

Quoting Pihero (Reply 29):
Not quite, the report specifically says : "However, the Cockpit Voice Recorder (CVR) recorded at the time of the touch down the PIC's command "ok, flaps 20" together with several sounds which indicate the clicking of the TOGA lever and the movement of the speedbrake handle."

Surely the Data recorders would record the TOGA input to corroborate the audible button push. This seems inconclusive to me.

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Pihero
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RE: Last Year B777 Missed Landing

Mon May 07, 2012 5:51 pm

Quoting tdscanuck (Reply 33):
You can't switch from "Approach" to "Rollout" mode. ROLLOUT is a heading control mode. The equivalent mode in the air is LOC, not APPROACH (the altitude mode would switch from G/S to FLARE). There is no FMA annunciation of "APPROACH" on a 777.

OK ; Please enlighten us on what 's happening to the airplane at the threshold . What mode does the "ROLL OUT" replace, and is it still dependent on LOC signal ? GPS ?

Quoting sandyb123 (Reply 37):
surely the FO should not have made the input?

NBo . The captain was PF, the F/O, perforce became PM. He shouldn't have interfered (which puts to rest all the twaddle about Airbuses hidden flight controls and pilots unaware of what their colleague is doing.)

On this incident, as soon as the landing geometry showed a touchdown outside the runway lateral boundaries, a go-around should have been executed. That it didn't happen is testimony of either a not-optimum CRM inside' the crew or some ergonomics issue with the T7 TOGA switch, or both.
Quite funny that we hear of this nearly six months after it happened. Had it been an Airbus, I'm not so sure it would have been hidden for the same period.
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tdscanuck
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RE: Last Year B777 Missed Landing

Tue May 08, 2012 1:01 am

Quoting sandyb123 (Reply 37):
The rudder is used every day on cross wind landings or to kick out any changes in the final stages of flight.

It's used on crosswind, yes, but no training program I know of advises using it to "kick out" final orientation at touchdown unless you're taking out a crab.

Quoting sandyb123 (Reply 37):
IIRC the autopilot has no rudder authority and wouldn't have used it in any case as logically (it's logic) there was nothing wrong.

Most autoland autopilots have rudder authority; it's the only way to do crosswind autolands.

Quoting Pihero (Reply 38):
OK ; Please enlighten us on what 's happening to the airplane at the threshold . What mode does the "ROLL OUT" replace, and is it still dependent on LOC signal ? GPS ?

When you're on the beam (assuming an ILS), the FMA should be SPD | LOC | G/S (speed mode | heading mode | pitch mode). The armed modes would be - | ROLLOUT | FLARE. As you pass through ~50' it should switch to SPD | LOC | FLARE. At about 30' is will go to IDLE | LOC | FLARE. After touchdown, IDLE | ROLLOUT | FLARE.

ROLLOUT replaces LOC. It's still tracking the localizer (if you were on an ILS) but is using rudder & nosewheel instead of bank to hold centerline. If you were on a GLS it would be using GPS.

Tom.
 
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RE: Last Year B777 Missed Landing

Tue May 08, 2012 1:30 am

Quoting BA777 (Reply 15):
Surely if in any doubt, disconnect and fly the plane manually and go around if necessary and come in again.

That is something I really think about. I am an ATC, and private pilot, not really experienced with heavier of fully automated aircraft. I don't really know what the procedures are for this specific aircraft on this situation, but I think that if we can override the autopilot in critical situations would be a safer option. I say this just based on the idea that pushing a button, TOGA, would correct the problem, even when it is able to do so and designed to do so, is kind of risky.
If the conditions were marginal, good, keep the autopilot, but with good visibility I don't think I would continue relaying on it, at least more than manual control.

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RE: Last Year B777 Missed Landing

Tue May 08, 2012 3:32 am

Quoting tdscanuck (Reply 39):
At about 30' is will go to IDLE | LOC | FLARE. After touchdown, IDLE | ROLLOUT | FLARE.

In this case, I'd assume that with that ROLLOUT indication on the FMA, Go Around is locked out as you're now in a "ground" mode. and the captain's attempts at GA were, by design, prevented from happening by the system.
That attempt at goAround cancelled the speedbrakes, which explains the aircraft vertical nose oscillations.
All in all, it could have been far worse and IMO, had they not interfere with the A/P, it would have brought them back on the runway centerline. Difficult to blame the crew, though, as we're not used to visit the sides of a runway... That explains, but certainly not excuse the F/O (PM) action on the rudder pedal.

As a conclusion, a smack in the face of the anti-side-stick brigade and their belief in the inherent superiority of "tactile feedback"," backdriven flight controls" from A/P inputs and God knows what.
This should, as a very good example of the importance of crew synergy over cockpit designs, close once and for all the debate : There is no ideal set up.
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RE: Last Year B777 Missed Landing

Tue May 08, 2012 5:06 am

Quoting Pihero (Reply 29):
Please note that here we have an example of a dual flight control input with an over-correction of the left deviation.
Could be the main reason for the runway exit.

LOL! never thought of it that way!
(But then, would dual input be announced when both pilots make rudder inputs on the bus FBW?)

Quoting Pihero (Reply 41):
In this case, I'd assume that with that ROLLOUT indication on the FMA, Go Around is locked out as you're now in a "ground" mode. and the captain's attempts at GA were, by design, prevented from happening by the system.

Go-Around guidance not available on ground.
Go-Around mode not available on ground.
Selecting TOGA once in ground mode does nothing.
Somewhere on the 777 FCOM I think...

Now why would Boeing lock-out Go-Around guidance and all the rest of it, once on ground? I'm sure there must be a good explanation (we're talking Boeing, like Airbus, not AVIC/Xi'an aircraft factory here!) and I sure would love to hear it!

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RE: Last Year B777 Missed Landing

Tue May 08, 2012 9:14 am

Quoting Pihero (Reply 41):
In this case, I'd assume that with that ROLLOUT indication on the FMA, Go Around is locked out as you're now in a "ground" mode.

The mode isn't exactly locked out but it won't do the transition from ROLLOUT to TO/GA without an extra step...cycle the flight directors. ROLLOUT comes on once the airplane goes from Air to Ground mode. A huge amount of systems reconfigure on that transition. Trying to go-around after you're on the ground isn't a go-around, it's a rejected landing. Different procedures, different actions required.

Quoting Pihero (Reply 41):
All in all, it could have been far worse and IMO, had they not interfere with the A/P, it would have brought them back on the runway centerline.

True if and only if the guidance beam was actually on the runway centerline. If the localizer was deviated due to some other object causing an issue, it would have gone to wherever the localizer was. That said, although bendy localizers aren't unusual and they're a bit off putting during autolands, they typically don't end up completely off the runway.

Quoting Pihero (Reply 41):
As a conclusion, a smack in the face of the anti-side-stick brigade and their belief in the inherent superiority of "tactile feedback"," backdriven flight controls" from A/P inputs and God knows what.

Where did that come from?

Quoting mandala499 (Reply 42):
Now why would Boeing lock-out Go-Around guidance and all the rest of it, once on ground? I'm sure there must be a good explanation (we're talking Boeing, like Airbus, not AVIC/Xi'an aircraft factory here!) and I sure would love to hear it!

The systems went through their air/ground transition. If you try to take off now you're talking about a rejected takeoff (aka touch-and-go), not a go-around. The procedures aren't exactly the same.

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RE: Last Year B777 Missed Landing

Tue May 08, 2012 11:30 am

Quoting tdscanuck (Reply 43):

Where did that come from?

Main argument of those who claim the superiority of "visual and tactile feedback" on moving flight controls : PM sees everything,; understands everything PF does and makes a success of his monitoring duties ; This example shows it's just a load of bull : PM intervened and made worse a situation, which in my opinion was well taken care of by George and the captain.

Quoting tdscanuck (Reply 43):
The systems went through their air/ground transition. If you try to take off now you're talking about a rejected takeoff (aka touch-and-go), not a go-around. The procedures aren't exactly the same.

On the bus, it doesn't make a difference between a GoAround or a rejected landing ( that is up to 30 seconds after touchdown)... Just push the TLs into the TOGA detent and have your trusted copilot announce the FMA changes.
We really need to be careful as the philosophies are really different ( for instance, LAND, FLARE and ROLLOUT are common pitch and roll modes on the 'Bus, hence my initial mistake ).
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RE: Last Year B777 Missed Landing

Tue May 08, 2012 1:29 pm

Quoting Pihero (Reply 44):
Main argument of those who claim the superiority of "visual and tactile feedback" on moving flight controls : PM sees everything,; understands everything PF does and makes a success of his monitoring duties ; This example shows it's just a load of bull : PM intervened and made worse a situation, which in my opinion was well taken care of by George and the captain.

If the PM takes control without telling the PF I'm not sure how that's an indictment of the control inceptor philosophy; no airliner is ever designed for dual input. If the PM had either stayed PM or taken control as PF the result would be different...making an input without telling the PF what you're doing is against all procedures I know of, whether on an Airbus or Boeing.

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RE: Last Year B777 Missed Landing

Tue May 08, 2012 2:54 pm

Quoting Pihero (Reply 24):
2/- It seems to me that the switch over to the "Roll out" mode from the "Approach" mode was a bit quick : what are the required conditions : only one gear contact doesn't sound right to me.
3/- The DFDR doesn't show any"Go Around" selection, but the Captain said it did and the CVR recorded the call for a reduced flap setting (part of the manoeuvre ). So what in reality did happen ?

AP-L immediately went to ground mode 11:09:16 (when 1st wheel touched)
AP-C went to ground mode at 11:09:20
AP-R went to ground mode at 11:09:18
AP Roll out Armed went to active as soon as RA reached 2feet RA per design (11:09:16)
Times mentioned above are "start of transition to next mode", transitions last approx 1 second.
I assume that as soon as ROLLOUT mode is active, TOGA activation is inhibited as per stated in the FCOM as The TO/GA switches are inhibited when on the ground and enabled again in the air for a go-around or touch and go."

Quoting tdscanuck (Reply 33):
You can't switch from "Approach" to "Rollout" mode. ROLLOUT is a heading control mode. The equivalent mode in the air is LOC, not APPROACH (the altitude mode would switch from G/S to FLARE). There is no FMA annunciation of "APPROACH" on a 777.

I'll elaborate on yor posts regarding this:
FMAs:
Below 1500RA: SPD, LOC (ROLLOUT armed), G/S, LAND 3.
40-60ft RA: SPD, LOC (ROLLOUT armed), FLARE, LAND 3
25-50ft RA: IDLE, LOC (ROLLOUT armed), FLARE, LAND 3
2ft RA: IDLE, ROLLOUT, FLARE, LAND 3

Quoting Pihero (Reply 41):
That attempt at goAround cancelled the speedbrakes, which explains the aircraft vertical nose oscillations.

Funny, TOGA switches should be inhibited. Unfortunately we have no thrust lever angle readouts at the released FDR plots... would love to know how it retracted.

Quoting Pihero (Reply 41):
This should, as a very good example of the importance of crew synergy over cockpit designs, close once and for all the debate : There is no ideal set up.

I agree... there is NO IDEAL SET UP.

Quoting tdscanuck (Reply 43):
The mode isn't exactly locked out but it won't do the transition from ROLLOUT to TO/GA without an extra step...cycle the flight directors.

It seems locked out by the FCOM:
This is nitpicking I know, but...:
Under the Automatic Flight system description on the 777 FCOM, under Go-Around:
"Pushing either TO/GA switch activates a go-around. The mode remains active even if the airplane touches down while executing the go-around."
BUT...
"The TO/GA switches are inhibited when on the ground and enabled again in the air for a go-around or touch and go"

And in the FCTM:
"If a go-around is initiated before touchdown and touchdown occurs, continue with normal go-around procedures. The F/D go-around mode will continue to provide go-around guidance commands throughout the maneuver.

If a go-around is initiated after touchdown byt before thrust reverser selection, auto speedbrakes retract and autobrakes disarm as thrust levers are advanced. The F/D go-around mode will not be available until go-around is selected after becoming airborne"

And on Rejected landing as well as:

Quoting tdscanuck (Reply 43):
The systems went through their air/ground transition. If you try to take off now you're talking about a rejected takeoff (aka touch-and-go), not a go-around. The procedures aren't exactly the same.

(I assume "now you're talking about a rejected landing").
"A rejected landing maneuver is trained and evaluated by some operators and regulatory agencies. Although the FCOM/QRH does not contain a procedure or maneuver titled Rejected Landing, the requirements of this maneuver can be accomplished by doing the Go-Around Procedure if it is initiated prior to touchdown. Refer to Chapter 5, Go-Around after Touchdown for more information on this subject."
Going around in circles on this... This is like Boeing saying, "U're on your own when rejecting a landing"... it's cynical of me I know! Shouldn't be a problem with manual landings, but the autoland mindset and then reject the landing, does sound like "you're on your own" in Boeing.

So, the way I see it, the correct procedure to reject a landing is to change to a Touch-and-go mindset... which is only for training...
"The Trainee should do a normal final approach and landing. After touchdown, the instructor selects flaps 20, sets stabilizer trim, ensures speedbrakes are down and at the appropriate time instructs the trainee to move the thrust levers to approximately the vertical position (so engines sabilize before applying go-around thrust). When the engines are stabilized, the instructor instructs the trainee to set thrust.

At VREF, instructor calls "ROTATE" and the trainee rotates smoothly to approximately 15deg pitch and clim at VREF + 15 to 25kts. The take off configuration warning siren may sound momentarily if the flaps are not retracting to flaps 20 and the thrust levers are advanced to approximately the vertical position."

Or yes... just do the standard go-around... which, they did... but didn't work...
The manual flap selection to 20 was done... the TOGA pressing was done... ensure/set go-around thrust... not done... I guess they expected this to occur automatically... but... And Follow F/D commands... well... TOGA FMA never came...

"The FDR did not show any indications for the initiation of a go-around procedure. However, the Cockpit Voice Recorder (CVR) recorded at the time of the touch down
the PIC's command "ok, flaps 20" together with several sounds which indicate the clicking of the TOGA lever and the movement of the speedbrake handle."
So, TOGA was selected, but inhibited.

More emphasis on "Go-Around after touchdown" or "rejected landing" to include "perform manual go-around" might do some good here. The problem in this incident is that it was rejecting an automatic landing after touchdown. It's like a total grey area (depending on how you look at it). I don't think a manual landing would pose this kind of problem as there's less emphasis on activating to TOGA mode (ie: one can always put the thrust up first then press TOGA, or just the A/T d/c)... a luxury not available in the autoland mindset?

Quoting Pihero (Reply 29):
These are consistent with the drill " TOGA / Flaps... make sure speedbrakes stowed... announce FMA (which they never did ). On the other hand, those TOGA switches are not my favourite way of ensuring the go-around trigger.

Well...

Quoting tdscanuck (Reply 45):
making an input without telling the PF what you're doing is against all procedures I know of, whether on an Airbus or Boeing.

Yeaps... so many mishaps and near events and lucky escapes on these... but once in a while, they're not so lucky with dual inputs.

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RE: Last Year B777 Missed Landing

Tue May 08, 2012 5:18 pm

Quoting mandala499 (Reply 46):
Quoting tdscanuck (Reply 43):
The mode isn't exactly locked out but it won't do the transition from ROLLOUT to TO/GA without an extra step...cycle the flight directors.

It seems locked out by the FCOM:
This is nitpicking I know, but...:
Under the Automatic Flight system description on the 777 FCOM, under Go-Around:
"Pushing either TO/GA switch activates a go-around. The mode remains active even if the airplane touches down while executing the go-around."
BUT...
"The TO/GA switches are inhibited when on the ground and enabled again in the air for a go-around or touch and go"

There's an unwritten caveat there that falls out of where this text is located in the FCOM..."the TO/GA switches are inhibited when on the ground *after landing*". The TO/GA switches are obviously not inhibited all the time on the ground because that's how you set takeoff thrust in the first place.

This is why you cycle the flight directors when doing repetitive touch-and-go's. When the flight directors first come up they always come up in - | TO/GA | TO/GA. That arms the TO/GA switches. If you cycle the flight directors after touch down they "wake up" in TO/GA mode and you can use the TO/GA switches, even if you just landed and are still rolling.

If you land and don't touch anything, TO/GA won't do anything because the flight director won't go from IDLE | ROLLOUT | FLARE to - | TO/GA | TO/GA.

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RE: Last Year B777 Missed Landing

Tue May 08, 2012 5:22 pm

Quoting tdscanuck (Reply 45):

If the PM takes control without telling the PF I'm not sure how that's an indictment of the control inceptor philosophy

We're in total agreement. But if PM had been really comfy knowing - and seeing - what PF was doing, he would never have interfered... and you remember that still IS the main gripe A.netters have against Airbus.
I enjoy twisting a few noses a bit, from time to time.

Quoting mandala499 (Reply 46):
the correct procedure to reject a landing is to change to a Touch-and-go mindset... which is only for training...

Somewhere in that drill there's a reset of the Flight Director switches, IIRC, if that architecture is 744-like.
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RE: Last Year B777 Missed Landing

Tue May 08, 2012 7:35 pm

Quoting tdscanuck (Reply 47):
If you land and don't touch anything, TO/GA won't do anything because the flight director won't go from IDLE | ROLLOUT | FLARE to - | TO/GA | TO/GA.

Interesting ... so its entirely possible they hit the TOGA switch and it simply didn't do anything?