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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.
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.
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.
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.
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?
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.
The engines responded - they just dont spool up that quick from idle. [edit on 18/1/2008 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.
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.
Originally posted by Darkpr0Also, on the subject of the control surfaces, would the elevators/ailerons be electronically assisted when power is present as well?
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.