BA Flight lands short of Runway

[LSainsbury]

I went past Heathrow on the M4 at about 5pm - quite heavy traffic but nothing unusual, but the M25 was rammed. Mind you - it normally a car park anyway!

My money is on a bird ingestion event...

[SMHarman]

Originally Posted by Uncle Peter

Sorry yes as BBKing says the net effect is that the airspeed of the plane will drop once the event has occurred. If the aircraft is on autothrottle then it'll be the machinery itself getting it into a pickle.

and with low to no groundspeed the plane will stop before it even gets to the start of the runway?
I'm no expert at this but extrapolating what I am reading and understanding here and seeing that the plane stopped very quickly.

[BBKing]

Fascinating snippet of a mobile camera footage on Newsnight, but they never went back and reshowed it. They seemed to reach a fairly plausible consensus (despite Kirsty Wark having no clue) that the event struck quickly, late in the descent, no time to even get a mayday out, was unlikely to be loss of all power/electrics, was quite likely weather related and the flight crew did as good a job in the circumstances as could reasonably be expected, bringing the plane in level (no mean feat if you've not got flying airspeed, it only takes a wing to drop and you'll cartwheel it) and stopping slowly enough to avoid deceleration injury. I'm not sure about the latter being the crew's doing, though, since the ground's pretty soggy after days of rain round here.

We can estimate the rough landing length from Google Maps - about 1000-1200 feet from the last lighting gantry to where the plane stopped, which is about 1/3 the usual stopping distance, so about 3 times the deceleration if the plane had hit with landing speed, rather less if, as seems likely, the speed was down in the dirt (the video shows the nose pulled high but the plane sinking, suggesting very low speed indeed and being bled off in the air). Given that, the witnesses saying it was a hard landing but they didn't realise it was a crash until the masks came down, the doors came open, people shouted 'get off' and bits of undercarriage were visible through the wing seem quite plausible.

[Uncle Peter]

Just found this interesting article which explains how an Australian 777-200 experienced erroneous speed readings and warnings from one of it's primary systems causing the autopilot to throttle up. Perhaps it could also have happened the other way around, reporting overspeed and throttled back.

http://www.airlinesafety.com/faq/777DataFailure.htm

[Xaccers]

Originally Posted by SMHarman

and with low to no groundspeed the plane will stop before it even gets to the start of the runway?
I'm no expert at this but extrapolating what I am reading and understanding here and seeing that the plane stopped very quickly.

We used to do short landings in FlightSim by setting the wind directly along the runway so you'd either hover in flight, dive and move forward or pull back and move back.
There was a slight flaw in that when your wheels touched the ground, windspeed had no effect so you'd suddenly shoot along the runway!

[LSainsbury]

Captain Peter Burkill only discovered that his Boeing 777 had lost power when he was 500ft above London's rooftops.


He tried to apply more thrust as the plane sank dangerously low on its approach to one of the world's busiest airports.


But the engines failed to respond, leaving him with 30 seconds to decide how to handle the crisis.


Capt Burkill was forced to the land the jet carrying 136 passengers several hundred feet short of the runway.

Great sensationalism from Sky....

In that situation, there's only way - and that's down...no need to "decide" anything!

[tweetypie/8]

Originally Posted by Uncle Peter

Nasty, looks like the hallmarks of a low speed wind shear accident. Thank heaven nobody was killed or seriously injured.

the pilots done a fantastic job !!well done

[BBKing]

[Warning - amateur air accident investigation follows]

Fascinating pictures out on the web now - here's one:

http://www.heathrowpictures.com/pict...72_gymmm15.jpg

What some people are saying is that the little squished fan thing under the plane is the RAT - the turbine that provides emergency power to the aircraft's electronics in the case of loss of power - whether it deployed during the emergency (suggesting electrical failure) or was knocked out during the slide isn't tellable.

Elsewhere in the pictures the starboard engine's intake is full of dirt, suggesting the plane hit slightly right-wing down (since it slewed to starboard during the crash this is quite likely) and the engine's fan blades aren't showing any damage, suggesting that it quite possibly wasn't under power. The port engine, on the other hand, has quite a bit of dirt all round the disk, suggesting it was at least rotating, and most of the blades appear to have broken, which suggests quite a bit of energy in the engine. Good work by Rolls-Royce in that the engine appears to have contained the disk failure (note the scarring around where the sheared blades hit the inside of the intake, but none have come through the case).

Also BA are saying that the 'hero pilot' wasn't Pilot Flying on the approach, the co-pilot was. British journalists, jumping to conclusions? Fancy.

Anyway, whoever was flying it, if it did indeed lose two engines on the approach, getting it down without serious injury was good work all round, but it was a damned close run thing. If it only lost the starboard they should have made it, so there are questions to answer.

http://www.heathrowpictures.com/pictures/pictures.html

Try it yourselves:

Port: http://www.heathrowpictures.com/pict...772_gymmm3.jpg
Starboard: http://www.heathrowpictures.com/pict...72_gymmm20.jpg

[r1ch]

I noticed that the RAT was out in that picture earlier but I figured that it must have been pulled out as it dragged along the ground. The crash pulled off the undercarriage, so it doesn't seem like the RAT would stay attached during the initial impact - could easily be wrong though.

The initial report from the AAIB says:

Following an uneventful flight from Beijing, China, the aircraft was established on an ILS approach to Runway 27L at London Heathrow. Initially the approach progressed normally, with the Autopilot and Autothrottle engaged, until the aircraft was at a height of approximately 600 ft and 2 miles from touch down. The aircraft then descended rapidly and struck the ground, some 1,000 ft short of the paved runway surface, just inside the airfield boundary fence. The aircraft stopped on the very beginning of the paved surface of Runway 27L. During the short ground roll the right main landing gear separated from the wing and the left main landing gear was pushed up through the wing root. A significant amount of fuel leaked from the aircraft but there was no fire. An emergency evacuation via the slides was supervised by the cabin crew and all occupants left the aircraft, some receiving minor injuries.

Initial indications from the interviews and Flight Recorder analyses show the flight and approach to have progressed normally until the aircraft was established on late finals for Runway 27L. At approximately 600 ft and 2 miles from touch down, the Autothrottle demanded an increase in thrust from the two engines but the engines did not respond. Following further demands for increased thrust from the Autothrottle, and subsequently the flight crew moving the throttle levers, the engines similarly failed to respond. The aircraft speed reduced and the aircraft descended onto the grass short of the paved runway surface.

[BBKing]

Presumably the autothrottle-initiated increase was related to the final flap selection, which obviously requires an increase in thrust. In a high-drag configuration with no extra power on tap (so no chance of a go-around) there's only one direction you're going.

The AAIB saying that the speed reduced while height reduced suggests lack of thrust and presence of lots of drag, of course. It'll be interesting to understand the reasons for the asymmetric engine damage, though.

[Hom3r]

The RAT (Ram Air Turbine) normally deploys when the plane losses electrical power, and I'e been told that it deploys this a loudish thud.

You could say it looks like a fan, and produces enough power for the most importal controls/instruments

The above links don't currently work.

[Mick]

Originally Posted by BBKing

so there are questions to answer.

One thing is for sure - as we know in situations involving incidents with commercial jets - no stone will be left unturned. Even if it takes the investigators or "tin kickers" years to establish a cause, they don't like having any plane incident undetermined because they cannot correct the probable cause which could strike again in another plane.

[Warning - Some Air Investigation history coming up]

You only have to look at the case of the jamming rudder PCU servo valve issue, involving three flights but all the same model plane, the Boeing 737. In this case which took investigators 10 years to solve (one of the longest investigations in aviation history).

What happened? If you can recall, two of the three planes were ripped from the sky due to one small minuscules problem in the rudders PCU servo valve which controls the movement of the Rudder. In both incidents - the rudders PCU servo valve would jam and malfunction forcing the two planes to go an unrecoverable pitch to nose down position.

One of the main reasons it took so long to determine the absolute cause of the crashes of both B737's is that the rudders PCU servo valve, upon previous inspection left no evidence of any malfunction, it was only when a thermo shock test was performed that investigators saw with their own eyes that the servo valve jammed and then the valve would then only work in reverse mode, thus any commanded action taken by the pilots meant the opposite effect on the rudder, so in essence, what the pilots didn't know and will never know is that they were actually steering their plane to the ground.

Other contributory evidence came to light too when the third flight involving a B737, when the same rudder hard-over malfunction occurred but the pilots managed to land safely giving investigators a plane that was intact and pilots that were alive and able to tell them their version of events.

[Octal]

I bet there are some very concerned people over in Boeing at the moment.

[BBKing]

The above links don't currently work.

Too true - evidently I posted them on here just as a couple of thousand other people did the same, since the URL was plastered all over the BBC Six o'Clock News coverage.

[SMHarman]

This was the first serious accident for the 777 since it began commercial service in 1995.
12+ years of safe service
http://www.telegraph.co.uk/travel/ma...athrow-117.xml
Says there are 667 in service
http://en.wikipedia.org/wiki/British...ys_Flight_BA38
Says this one G-YMMM is c/n 30314/342
so a finger in the air guess makes it around 5-6 years old.
http://en.wikipedia.org/wiki/Boeing_777#777_sales
Looking at delivery numbers here this was 'craft was delivered in 2001.

http://www.airliners.net/open.file/1313756/L/

I'd think Boeing are more concerned with getting the 787 off the ground than this.