Sorry if posted before...

The pilots did an amazing job but this guy also deserves praise for remaining so cool under pressure!

BBC News - 2008 BA Boeing 777 Heathrow crash: Air traffic control

Just another day at LHR ATC!!!

Cheers, Mark

 

Thanks for that-it was shown before in fact.

Yes all concerned did a first class job, they kept their heads in a particularly unpleasant emergency and carried out the only correct actions to make it over the fence onto the grass.

That would go a long way towards an AFC in the RAF!

Les

 

Les, what is an AFC??? Tried to google it but only get details about Arsenal, or RAF appointments followed by those letters.

 

Air Force Cross - for courageous flying outside of the combat zone iirc

 

Here you go

Ministry of Defence | Defence For... | Veterans | Medals | Air Force Cross

 

They were very lucky on that 777 flight.
As the engines spooled-up to counter the increase in flap for landing, they dragged ice that had accumulated in the aircraft fuel pipework into the engines' fuel / oil heat exchanger. The ice then blocked the fuel flow to each engine, causing the engines to remain at roughly flight idle, which wasn't enough to keep it airborne.

Oddly, the only way that they could have recovered, was to pull the throttles back to idle, and then re-apply power! Given that no one had ever experienced this phenomenon before, the flight crew did a pretty amazing job at cleaning up the aircraft and hopping over an aerial installation that could have led to a very different outcome if they'd hit it.

 

I read somewhere that this problem was, in part, due to the aircraft industries drive to save fuel. Until recently, aircraft would give the engines full throttle periodically thru a flight and this helped keep the build up of ice unlikely. Flying at partial throttle for long periods can, apparently, result in ice buildup.

Thanks to the "Green Brigade" - NOT

You have to research changes in scope and operational changes PROPERLY.

Cowtowing to the "Popularist Genre" isn't neccesarily the correct thing to do - As this case appears to support.

 

Looks like that one is covered for you.

I heard that the captain was the victim of a whispering campaign by other employees of the airline and was effectively forced to leave their employ and is looking for another flying job. Don't know whether it was jealousy at his success in saving all those lives. It is surprising how such nastiness can show up in cases like this.

Les

 

It might interest you to know that no-one strives to safe fuel as much as the airlines. The "green" benefits are incidental.

No pilot is going to apply "full throttle" during flight, if he doesn't have to, for this reason.

What you might be confusing is the stepped climb using VS instead of VNAV.

In VNAV mode, the autothrottle sets the engine thrust to achieve maximum climb thrust. The autopilot then uses elevator commands to control the airspeed to the VNAV target speed set in the Flight Management Computer (FMC).

In VS mode the autothrottle modulates the engine thrust to maintain the speed set on the MCP. The autopilot uses elevator commands to control the aircraft’s vertical speed to the vertical speed/flight path angle set on the MCP.

If VNAV had been used to climb to higher flight levels then it's possible, no one really knows, that this incident might not have happened.

I should say that both modes of climb are allowed, and in BA's case VS is the SOP so the pilots were simply following company procedure.

 

Did the plane survive this, is it back in service ?

Wasnt this mainly down to poor quality fuel with water in it ?

 

I doubt that it would be repairable J4CKO, it had a good thumping on that arrival. They will probably flog all the salvable bits off to the secondhand aircraft spares dealers. Its quite a big industry I hear.

It was probably down to poor quality fuel, I have forgotten where they picked up fuel but I think that possibility was mentioned at the time. Seeing those pictures on the tv, that seemed a hell of a lot of water just from a normal refuel. We had drains in the fuel tanks on ours and one of the checks was to drain off the water and fuel until it ran as pure fuel. You always get a bit of condensation over time, but not in the same league as in those pipes.

Les

 

No, no and no. ;-)

 

I read about it subsequently and it has indeed now been broken up, not sure how much got re-used.

As for the third no and the winky thing, come on spill the beans !

 

Isn't there an additive you can take on when fueling, which stops ice forming in jet fuel? Supposed to be pretty nasty staff - I can't remember its name.

 

nothing to spill Jacko. You asked 3 questions, the answer was no x3. Hence the wink.

 

Water in fuel is an industry problem, caused by storing large volumes in tanks, which naturally create condensation.

Military jets generally get round this problem by including additives in the fuel, but most commecial airliners are not approved for using the additives and so have to cope with an amount of 'dissolved' water. There is a spec which allows up to x% water in the fuel.

There was no problem with the fuel in G-MMMY - it was extensively tested and found to exceed the required specs. The issue was that, at certain temperatures, the water (ice) could adhere to the insides of the main fuel pipes to the engines - over time, this ice can build up in significant quantities.

The engines had been running at pretty much a constant throttle setting for a significant portion of the flight - it was only when the throttles were advanced at the very end of the flight that the increase in fuel flow dragged off the accumulated ice, blocking the entry to the heat exchanger.

The heat exchanger was tested as part of the engine certification, which it easily passed. However, the particular design meant that it was susceptable to be blocked if by large amounts of ice. The part has now been redesigned, and these have already been fitted to a large proportion of the 777 fleet (and also potentially affected Airbus aircraft). The method to change to higher flight levels has also been changed on 777 aircraft, which requires a higher throttle setting, which should dislodge any ice accumulations during flight.

Very little is known about ice acumulation in aircraft fuel systems (partly why this AAIB report has taken so long to be issued). It is worth noting that the rig tests could only block the engine's fuel supply by injecting around 100 times the acceptable amount of water into the fuel system.....so the reason why ice affected this one flight, and no other, is still a bit of a mystery....

 

Thanks for the explanation DaveD.

As I explained above we used to drain the unsdissolved water out of the tanks. We did have additives in our fuel, one of which was to stop algae forming in the tanks and pipes as well. Think it was called "FSII"

Les

 

Dave, thanks for that, very interesting.

 

Indeed, the A/C did 2 VS climbs whilst in the cruise... which is where the problem came from (probably).

I think the main issues were down to them not taking the AP off when the roll back started and they ended up below the GS. They might have got her to the thold had they taken the AP off sooner.

Either way, I would have been quite happy to get out of that one.

 

DaveD, Thanks for your input in this thread, really interesting and insightful.

Quite refreshing to read a thread without it degenerating into trolling and bickering.

 

Give it time FM.

 

 

If anybody fancies a long read, then the full investigation report by the AAIB can be downloaded from here:

http://www.aaib.gov.uk/sites/aaib/cm...0%20G-YMMM.pdf

The lengths that the investigators went to in their quest to find out what, and then why this happened is quite staggering.

 

Thanks for that, will have a read later.

Les