BA 777 crash at heathrow

page: 3
10
<< 1  2    4  5 >>

log in

join

posted on Jan, 19 2008 @ 04:05 PM
link   
I found out that on 777s you can find RR, PW, or GE engines. Someone earlier said this one had RR..is that confirmed..I can't tell by looking anymore. Then as for the GE there could actually be three flavors of controls .. The guys reponsible for the GE controls as of Fri afternoon do not think it had their controls. Keep in mind that it is hard to have a fault tolerant system if there is no power.. I was right that at least on GE controls they have both alternator and 115 VAC power. Considering the dual redundancy of the controls something quite catastrophic would have to happen for all power to be lost.




posted on Jan, 19 2008 @ 04:08 PM
link   

Originally posted by johnlear

I thank the good Lord Above daily, that I was able to retire before I ever had to fly an airplane that used fly by wire technology.

I often think of the pilots of Swissair 111 who spent the last few minutes of their lives back in First Class not only because of the fire in the cockpit but because every means of controlling the aircraft had been disabled by the fire.


Your two paragraphs do not quite gel together - Swiss Air 111 was an MD-11 aircraft, which had conventional hydraulic assisted direct linkage controls and not fly by wire controls. I am not quite sure why you mentioned Swiss Air 111 at all.



posted on Jan, 19 2008 @ 04:13 PM
link   

Originally posted by BlackProjects
I found out that on 777s you can find RR, PW, or GE engines. Someone earlier said this one had RR..is that confirmed..I can't tell by looking anymore.


Yes, the engines were two Rolls Royce Trent 800s.


Then as for the GE there could actually be three flavors of controls .. The guys reponsible for the GE controls as of Fri afternoon do not think it had their controls. Keep in mind that it is hard to have a fault tolerant system if there is no power.. I was right that at least on GE controls they have both alternator and 115 VAC power. Considering the dual redundancy of the controls something quite catastrophic would have to happen for all power to be lost.


GE were not responsible for the 777-200's control mechanism (they were not a risk sharing partner for the -200) and as such this plane would have had a Rolls Royce or Boeing subcontractor supplied engine management system. Specification wise, all offerings would have the same redundancy, and indeed 99% of the systems would be identical whether it was a RR, GE or PW engine.



posted on Jan, 19 2008 @ 04:33 PM
link   
Tx Richard..
The control guys said it was not a GE..usually if there is an IFSD(in flight shutdown) or similar serious event they hear very quickly. I figured specs were similar regardless...which as you say would lead to similar controls. In fact, I have no idea who might do RR controls maybe them? PW's are done pretty much by Hamilton Std I believe. GE's by BAe(although that facility has been Lockheed Martin and GE in the past). Still funny about the massive power loss though..
BP



posted on Jan, 24 2008 @ 05:56 AM
link   

Both engines of the British Airways jet that crash-landed at Heathrow Airport were still running when it came down, investigators have said.



US investigators have noted six previous engine failures in the same type of aircraft, it also emerged.


BBC

I was under the impression that this had been an fairly reliable aircraft? if it has now been released that it had suffered from engine problems in the past what else is there still to come out of the closet?



posted on Jan, 24 2008 @ 07:11 AM
link   

Originally posted by solidshot

I was under the impression that this had been an fairly reliable aircraft? if it has now been released that it had suffered from engine problems in the past what else is there still to come out of the closet?


6 engine failures in a world wide fleet of over 600 aircraft and 10 years since entry into service is actually damn reliable.



posted on Jan, 24 2008 @ 07:33 AM
link   
.....This BA 038 type 777was coming from Beijing,. This was an extreme range flight I havent seen the tjme mentioned, probably in excess of 22hrs, with extra crew against the prevailing wind (jetstream?) .
.....Was the aircraft on time or late?
.....There was only a small fuel spillage after the crash .
...Some reference was made that they had plenty of fuel for another half hour..which seems tight to me, I suppose they had Gatwick declared as an alternate by then.What were the actual and legally required reserves.?
.....The quoted use of the words " complete power failure" are a little ambiguous,Engine ? or Electrical?
....Pictures of engine damage after crash seem to indicate
one engine.may still have been giving some power, the other not.
....What was the required fuel management in regard to crossfeeds and booster pumps with low fuel and nose high attitude?
.....If there was some difference in engine power out put due to failure or partial starvation, the question of unlikely double failure of throttle control does not arise, though a single failure might then have occurred on the "good" engine.
.....Reports of conditions at the time refer to gusts and 40 kts aloft and 15 at the surface. Windsheer at 600 ft with poor response from throttled back engines might well have felt like "Loss of power"
....BUT whatever, hats off to copilot for mushing it over th fence ont a nice patch of soft grass..WOW!



posted on Jan, 24 2008 @ 10:57 AM
link   
...Ive had triple engine failure due to contaminated jellified kerosine .Indications were, run down and loss of power ,not instantaneous. Luckily I had a fourth kept going. ...Im wondering about cockpit check philosophy and crossfeeds and booster pumps in a nose up attitude after a 22 hour flight with a nominal half hour fuel remaining, and a some wind sheer to deal with .
... In my day the standard British cockpit checks were read out and done by usually the co pilot and counter checked by another crew member.Came the Boeings and 2 pilot crews with added work loads they changed to shared checks, each pilot did his own side and checked himself only...no cross checks.
...In this case with copilot handling how were checks being done, at a late and busy stage? certainly I completely understand that having decided to give a humdrum landing to the copilot ,it would have been difficult to switch duties at 500 ft without presenting the co with new problems.At least the Capt could concentrate on perhaps precise decisions as to what and when to do in the remaining seconds



posted on Jan, 24 2008 @ 11:50 AM
link   
reply to post by wilyflier
 


Agreed wily and welcome as well.

The point about the co-pilot keeping control was something that i mentioned briefly earlier and the one point about fuel spillage I actually heard there was quite a lot not the little that you stated. Also its come to light that both engines where producing power but at a must smaller amount then required and did not respond as said before.



posted on Jan, 24 2008 @ 11:55 AM
link   

Originally posted by Canada_EH

The point about the co-pilot keeping control was something that i mentioned briefly earlier and the one point about fuel spillage I actually heard there was quite a lot not the little that you stated. Also its come to light that both engines where producing power but at a must smaller amount then required and did not respond as said before.



In its update, the AAIB said the Boeing's twin Rolls-Royce engines initially responded to the request for thrust, but after three seconds the thrust of the right engine reduced and after eight seconds there was a thrust reduction in the left one.


BBC

looks like for some reason there was either a fuel blockage or the engine management told then to back off the power instead of increasing it?



posted on Jan, 24 2008 @ 12:08 PM
link   



The engines responded - they just dont spool up that quick from idle. [edit on 18/1/2008 by RichardPrice]



Interesting - and civilized - discussion.

About how long does it take for the engines to spool up?



posted on Jan, 24 2008 @ 12:43 PM
link   
Originally posted by RichardPrice


Your two paragraphs do not quite gel together - Swiss Air 111 was an MD-11 aircraft, which had conventional hydraulic assisted direct linkage controls and not fly by wire controls. I am not quite sure why you mentioned Swiss Air 111 at all.



WOW! Thanks Richard. This is what I love about ATS! You get instantly corrected for a mistake. I was under the false impression that the MD-11 was fbw.

I read your post and thought "Wait a minute….whats going on here." I immediately called Rod Boone who was in production test at Lockheed on the 1011 but had flown the MD-11. (Not that I didn't think your were absolutely correct.)

He said that with a total electrical failure in the MD-11 you would not have had control over the engines (he thinks they would go to MCT ) or pitch. But you would have aileron and rudder.

What do you think Richard?



posted on Jan, 24 2008 @ 01:57 PM
link   
reply to post by johnlear
 


Well there was issues with the hydraulic system and its operation or at least appeared to be when the TSB examined the wreckage.


The shut-off valves associated with the reversible-motor pumps were found to have been closed at the time of impact when it would be expected that, given the configuration of the aircraft, at least one set of valves would have been open, allowing one of the reversible-motor pumps to operate. Although the reason for the valves being in the closed position could not be determined, it could be attributed to several scenarios associated with fire-related electrical anomalies.


www.tsb.gc.ca...

All primary and secondary flight control surfaces are hydraulically powered by two aircraft hydraulic systems.

Other than the slats, which are electrically controlled and hydraulically actuated, the flight control system is designed with a direct mechanical/hydraulic interface consisting of cables that run between the cockpit controls and the various hydraulic actuators that move the control surfaces. Therefore, with the exception of the slats, the movement of the control surfaces does not depend on the availability of electric power.



posted on Jan, 24 2008 @ 06:17 PM
link   
A few more photos:

















posted on Jan, 24 2008 @ 07:02 PM
link   
Look at the gout of dirt the right-side engine took out of the ground! It's absolutely astounding that the engines managed to hold together enough to avoid injury considering the forces involved in such an accident.

Also, on the subject of the control surfaces, would the elevators/ailerons be electronically assisted when power is present as well?



posted on Jan, 24 2008 @ 08:24 PM
link   

Originally posted by Darkpr0Also, on the subject of the control surfaces, would the elevators/ailerons be electronically assisted when power is present as well?


If both engines should flame out there will still be some pitch and roll control available to keep the blue side up until the RAT is deployed and spooled up (about 20 seconds) and the APU started and on bus
(about 50 seconds), the elevator trim electrical operated supported by the standby bus (batteries) and the outboard ailerons driven by two electrical pumps from the standby bus.

There would also be some hydraulical pressure from windmilling engines even at low speed.

[edit on 24-1-2008 by Freaky_Animal]



posted on Jan, 25 2008 @ 08:11 AM
link   
Ive been out of it a long time, but seem to remember last ditch drill for low fuel or engine stoppage was"open all crossfeeds" ...with all its implications.
.
...Iam also reminded about a controversial low level "double Fadec failure" in a fatal RAF helicopter crash at Kintyre Scotland about 20 years ago .Nothing ever proved, and the pilots disgraced



posted on Jan, 27 2008 @ 09:35 AM
link   
........Further reading of variousaviation posts shows some ADs about freezing affecting the non electronic components of FADECS in icing fog at low powers.And on monitoring fuel specs BEFORE flight into specially cold conditions and fuel temps IN flight. in order to avoid fuel congealing into wax.
........Fuel specs call for working at temps down to various figures around minus 50 to minus 40 deg c .These temps are apparently monitored in flight, with instructions to find a warmer altitude ;and even divert if this causes increased
consumption
.......Suppositions
.....Fuel usually has some means of being stirred ,or heated in the tank,some of this by a small recirculation of warm fuel from the engine at normal full power.the descent from cruise height called for a long period of reduced power and reduced recirc flow?
....Beijing to London Great Circle route was a trip of 22 to 24 hrs and oats were minus 70 degrees c which gave the wing tanks a long cold soak . Perhaps when fuel was uploaded at Beijing with the best local spec(-50) there was still a large slug of fuel remaining from the previous flight with a lesser spec (-40)
Anyhow if the fuel ever got down to minus 55 or lower there would have been plenty of candlewax in the system, jamming the FCUnits(Fadecs)



posted on Feb, 18 2008 @ 03:30 PM
link   
Reply 75 from BA 777 Off Runway At LHR - Part 9

Not sure if this is official as next interim release was due out this weekend

www.airliners.net...


Quoting AAIB Interim Report:

Detailed examination of both the left and right engine high pressure fuel pumps revealed signs of abnormal cavitation
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 assessed both pumps as still being capable of delivering full fuel flow.


Quoting AAIB Interim Report:
Initial results confirm that the fuel conforms to Jet A-1 specifications and that there were no signs of contamination or unusual levels of water content.


Quoting AAIB Interim Report:

Some small items of debris were discovered in the following locations:

1. Right main tank – a red plastic sealant scraper approximately 10 cm x 3 cm under the suction inlet screen
2. Left main tank, water scavenge inlet - a piece of black plastic tape, approximately 5 cm square; a piece of brown paper of the same size and shape, and a piece of yellow plastic.
3. Right centre tank override pump – a small piece of fabric or paper found in the guillotine valve of the pump housing.
4. Left centre tank water scavenge jet pump – small circular disc, 6 mm in diameter, in the motive flow chamber.

The relevance of this debris is still being considered. Examination of the fuel surge tanks showed no signs of blockage of the vent scoops and flame arrestors. Neither pressure relief valve had operated; the relief valves were tested and found to be operate normally.


My Summary:
1. Both High pressure Fuel pumps (part of the engine) at some recent time in operation have sucked vapors

2. Both HP fuel pumps were still capable of full operation

3. No signs of fuel contamination by water or other contaminents

4. The right main tank main inlet had a possible blockage from a scraper
however the other potential blockages in the left main tank
deal with water scavenging not the main fuel inlet. Center tank
was supposed to be empty at this point.

No wonder its taking awhile to pinpoint the what happened prior to crashing and what transpired adter the crash., vis a vis fuel shutoff valves and transfer valves.

Almost brings directed energy EMI back in the picture affecting electronic
controls dealing with fuel

Apparantly it's the real deal
www.aaib.dft.gov.uk...



[edit on 18-2-2008 by Eagle1229]

[edit on 18-2-2008 by Eagle1229]

[edit on 18-2-2008 by Eagle1229]

[edit on 18-2-2008 by Eagle1229]



posted on Feb, 18 2008 @ 06:27 PM
link   
They went through two periods of flight where they were down to as low as -76C at altitude. Both were over China/Russia. They were initially instructed to climb to FL341, but didn't stay there because of extreme cold. They then dropped to FL315, until they were over the Urals. They climbed back up to FL348 at the request of ATC until after crossing, when they climbed up to FL380. At FL348 it was -65C, and went as low as -76C at FL380. The crew monitored temps of the fuel, and it didn't get close to freezing, but it could and probably did cause other problems for them at some point. The AAIB says fuel shouldn't fall below 3C above the freezing point, which on the 777 is -57C. That day it went to a minimum of -34C.

Both engines low and high pressure fuel filters were clean, both fuel heat oil exchangers were free of blockage, as were the fuel feed lines. The damage to the pumps is caused by either a blockage, or excessive aeration of the fuel. The accident board is attempting to recreate the damage in another pump.



[edit on 2/18/2008 by Zaphod58]





top topics
 
10
<< 1  2    4  5 >>

log in

join