Happy Landings

[David Morton]

Actually there is a lot in what you say Paul.
The index is a function of a variety of things within the company and even the profitability of a particular route. Other things that come into the equation are the Engineering costs, if the aeroplane is owned or leased, the fuel that has been uplifted to fly the sector, and so on. The crew are presented with a cost index at the top of the flight plan (it's called the Sword in BA) and the amount of fuel required to fly the sector. You can reduce the amount a bit if you want (mainly management and company men do that) though the majority usually utter forth in agreement with the Sword. A few always put more than sword on. Because they can.
I used to think that people who lived by the sword could also die by it.

 

[David Sturch]

How true. I also remember watching a show a few years back on parts suppliers it may have been 20/20. The parts where not inspected and remanufactured properly usually cleand up painted and signed off by some dubeous companies changing hands a few times. Some 3rd world airlines were using them because they would be a third cheaper than through the normal channel. There was also the rash of front landing gear failure on the Dash 7 in the last year. I never heard much more about it.

 

[Malcolm]

Post deleted, couldn't get animation to work properly!

 

[David Morton]

Paul, here is a link to the Cost Index and how it's calculated:
http://www.boeing.com/commercial/aeromagazine/articles/qtr_2_07/AERO_Q207_article5.pdf

If you need any of the abbreviations decoded, I'll try. Aviation is full of them. OK. BFN.

 

[TimB]

This was posted on another forum I frequent

Fuel is constantly mixed in the tanks. Water contamination is not the problem. If there was enough water in the fuel to cause flameout, the engines would have died long before takeoff. Each engine get fuel from its' own wing unless fuel is transferred. Aircraft attitude would only be an issue if he were flying inverted during approach. Don't want to get into the details of a fuel system, but attitude couldn't possibly be the problem.

The throttles are electronic and they do have a common component, the PCM (throttle assembly), or whatever they chose to call it.

The same mechanic services both (or all) engines frequently. What has been changed is that service requirements are alternated between engines. If all engines are serviced in such a was as to be a concern, ground runs are accomplished. ETOPS does have different requirements depending on engine type.

In the business we define ETOPS (extended twin operations) as Engines Turn Or People Swim.


Both engines quitting at the same time due to starvation is about as likely as two cars driving down the road running out of gas at the same time.

The engines will continue to make power even if ALL wing fuel pumps fail. There are no filters in the fuel system until the fuel reaches the engine. The fuel pumps (about 10) each have their own pressure indication. The engine monitors its' own pumps pressures.

If it were already in an emergency low fuel situation this may be possible, but not unannounced. Even if they ran out of gas, they would know about it for a minute or two before flameout. Although there is unusable fuel in the tanks, there isn't much.

The throttles are electronic, a failure in the wrong area can kill both systems.

 

[Paul Thompson 'Hooligan']

Thanks David - very interesting stuff...

Also - I heard that there was something in the press today about a mobile phone possibly being at fault - I just can't see this... I know that phones are not allowed to be used on planes, but surely all modern/current flight equipment is bombarded during EMC testing to ensure it's not adversely affected...

Came across this link on google..
RA EMC Awareness - Interference in Aviation and Aerospace

Anyone...?

 

[speed220mph]

Looks like the cause of the power failure on Flt 28 into Heathrow may have been a computer glitch according to a Sunday Times Online article. Interesting read: Hunt for fatal flaw of Flight 38 - Times Online

 

[Ken Mason]

From the Press Association this morning:

Both engines of the British Airways jet that crash-landed at Heathrow Airport were still running when it came down, investigators revealed today.
Disaster was narrowly averted when the Boeing 777, carrying 136 passengers and 16 crew, lost power in mid-air as it approached the west London airport on January 17.
American investigators have recorded six previous engine failures involving the same type of aircraft, it emerged today.
The most recent was in September 2006, when a Malaysia Airlines Boeing 777's right engine shut down near Brisbane, Australia.
The US National Transportation Safety Board's website lists another five incidents, including one in August 2005 where a 777 lost thrust after taking off from Perth, Australia.
A British aviation industry source stressed seven engine failures was "not a large figure" given the aircraft's long flight history and questioned how similar the previous incidents were to this month's BA crash-landing.
The Air Accident Investigation Branch (AAIB) issued an update today, indicating its inquiry into the Heathrow incident may be focusing on the aircraft's fuel supply system.
Various theories about what caused the jet to lose power have been put forward, including the possibility of fuel contamination.
The AAIB said it was carrying out a "detailed analysis and examination of the complete fuel flow path from the aircraft tanks to the engine fuel nozzles".
On Sunday, the stricken 150-tonne aircraft was painstakingly moved from Heathrow's southern runway to BA's nearby base, where it is being examined for clues.
In its latest update the AAIB repeated that the Boeing's twin Rolls-Royce engines had failed to respond to demands for more thrust as it came in to land.
It said: "The engines both initially responded but after about three seconds the thrust of the right engine reduced.
"Some eight seconds later the thrust reduced on the left engine to a similar level.
"The engines did not shut down and both engines continued to produce thrust at an engine speed above flight idle, but less than the commanded thrust."
Recorded data shows the aircraft had enough fuel and its autothrottle and engine control systems had worked as expected, the AAIB said.
The AAIB has said it intends to publish a preliminary report within 30 days of the incident.
The Boeing 777 is certified by the US Federal Aviation Administration (FAA) and its Rolls-Royce engines are certified by the European Aviation Safety Agency (EASA).
A spokesman for the Civil Aviation Authority said: "We regulate BA as an airline, so we need to be content they are meeting all regulations and requirements.
"As far as any modifications or inspections are concerned, that would come from the AAIB recommending it and the FAA or EASA making it a legal requirement after consulting with the manufacturer."

 

[Mike Trusty]

New approach lights at 27L LHR

http://www2.b3ta.com/host/creative/61345/1200695510/runway.gif

 

[David Morton]

Further release from the Air Accident Investigations Branch (AAIB)
reported on AOL news this evening:

The scene of last month's crash at Heathrow airport​

Investigators have found no evidence of a mechanical defect as the cause of the British Airways Boeing 777 crash-landing at Heathrow airport last month.

They also found the "black box" flight recorders indicated "no anomalies in the major aircraft systems", and ruled out ice, water or contamination of fuel tanks, a report from the Air Accidents Investigation Branch (AAIB) said.
But there was some damage seen to the engine high pressure fuel pumps and some small items of debris were found in the fuel tanks.
Not giving any cause of the January 17 accident, the AAIB said it was carrying out a full examination and analysis of the entire aircraft and engine fuel system.



Related Links

• Air Accidents Investigation Branch

The Boeing 777, with 136 passengers and 16 crew aboard, had flown to London from Beijing on January 17.
With the cockpit crew unable to get the required thrust from the engines as the plane approached Heathrow, the aircraft came down on the grass "some 1,000ft short of the paved runway surface and just inside the airfield boundary fence", the report said.
As the plane skidded across the grass and on to the end of the runway, the underpart of the aircraft collapsed. All occupants were safely evacuated, with one passenger suffering a broken leg and eight others receiving minor injuries. Four crew were slightly hurt.
Following an examination of the wreckage the report said: "Detailed examination of both the left and right engine high pressure fuel pumps revealed signs of abnormal cavitation (air bubbles) on the pressure-side bearings and the outlet ports.
"This could be indicative of either a restriction in the fuel supply to the pumps or excessive aeration of the fuel. The manufacturer (Boeing) assessed both pumps as still being capable of delivering full fuel flow."
The report went on: "Investigations are now under way in an attempt to replicate the damage seen to the engine high pressure fuel pumps and to match this to the data recorded on the accident flight."

 

[David Morton]

The AAIB have published their findings concerning the British Airways B777 crash landing on the threshold of 27L at London's Heathrow. Their finding is in fact inconclusive, and they have gone on record to say that ice in the fuel was the probable cause.
Oh really.
It's a very convenient finding because the ice would have melted long before the investigation started.
Somehow I think we are looking at an expedient rather than the actual cause.

Personally I think it is beginning to smell somewhat and I smell a rat.

 

[Pete McCluskey.]

Ditto David, I think we should start the GT40s sceptics club.

 

[David Morton]

Good idea Pete. Hereinafter named the SOF club.





Sceptic Old Farts ?

 

[Randy V]

Ditto X2 - Sign me up as an SOF as well....

I wonder how long it will take for the real story to come out of this?

 

[David Morton]

Randy - probably never. Loads of comment in the news today in a similar vein.
I can think of countless things to counter the Low Fuel Temp warning including loading -43c Freeze Point fuel but does China have such a thing? I know that Japan does for the Siberian route to London. Did it have any fuel to freeze up?
They (BA) said it had.

http://www.dailymail.co.uk/news/art...planes-ice-fuel-caused-BA-crash-Heathrow.html

 

[Scott Calabro]

Count me in too David.

The engines fuel filters would have stopped debris from getting to the fuel control units.

I still think they just used up all their fuel.

Cheers,
S

 

[domtoni]

Guys,

Like you, I can't believe it was ice in the fuel tank. Espically at such a low altitude.

Count me into the Skeptics club !!

Best
Dom

 

[Randy V]

I am having a hard time believeing that they would consider the public - many of which are quite learned - to buy off on all of this....


One thing I found almost humorous was this quote from the article you pointed to David;

One expert said, that in motoring terms, they have to 'gun the accelerator', even when that is not necessary. Asking pilots to do this inevitably increases fuel consumption.

In response to this I would have to say that NOT spooling up on final is a recipe for disaster should you have to execute a go-around / late missed approach... The thrust response is not immediate from an idle by any stretch in any turbine engine..

But it was the last sentence that struck me as a potential clue in the right direction. Not long ago, there were some pilots that refused to fly with only partial fuel loads thereby saving weight, fuel consumption and $$dollars$$ for the airline... So - I'm wondering - could this have played into it? As well as potentially running at higher throttle settings during the flight?
What about the potential foul-up of dumping fuel by mistake?

I purely cannot believe the ice crystals thing.. Those wings are cold yes - but aren't the leading edges fed ducted hot-air for deicing? Would that not increase the temp of the wings and thereby the fuel tanks?

 

[Ian Anderson]

Full report available here - on the site David posted earlier - made good lunchtime reading!

http://www.aaib.dft.gov.uk/cms_resources/G-YMMM Interim Report.pdf

Ian

 

[David Morton]

Just a couple of pointers Gents - By flying faster, and often to do this would be a reduction in altitude as well, the fuel can be warmed (relatively) to back above the Low Temp Warning level (nominally about
-43c) simply by friction. This is a frequent occurrence on the Polar or Siberian routes during the winter where the OAT (OUTSIDE AIR TEMP) can be as low as -70c or even lower. The fuel will obviously be heated during the final stages of low level and approach, but would still be in the order of -20c or colder, long after the aeroplane has been parked. It's usual to see Hoar frost on the underside of the fuel tanks up to a few hours after landing even in the summer. It can be a problem when an aeroplane is tanked up to full when it already has cold fuel on board and then there is a delay which results in venting and then requires fire service wash down and an even longer delay until it's declared safe again to board the talking freight. Most Rollers (RR engines) have a system of a fuel cooled oil cooler which by definition exchanges heat from the oil into the fuel, and this fuel is then used in the Engine.
Lastly, the leading edge hot air would not really have any effect on the wing tanks and can only be used while the LEDs (Leading Edge Devices such as droops and slats ) are retracted. Once they are extended Deicing has no effect and is inhibited.
Dave M