View Full Version : Was this a dangerous situation???
13th Jul 2001, 03:17
A question regarding a situation I was in..
I was on American Airlines flight from KORD to EGLL, a 777-200, when inflight just over the atlantic, fuel was coming out of engine number 2 at what looked like a high rate as a visible stream, and it was shut down. We flew to JFK on 1 engine, and landed with all the emergency services around the plane.
My question is this: Was this a slightly dodgy situation to be in, or do you think it was perfectly safe. The crew handled it very well, and AA gave me lots of air miles!!
While on the flight I was assuring my very scared friends of the wonders of ETOPs, however slightly on edge myself (especially when during the engine shut down, the lights and LCD displays etc. kept flickering on and off..)
cheers for any thoughts just for my interest,
The 777 flies very well on one engine, and AA pilots (like those in most airlines) are trained quite extensively in one-engine operations. Since there was no fire, and/or other apparent serious complication, it was probably not as bad as it might seem. It gets really "dodgy" when you have an engine fire that won't go out, or a fuel leak that is hard to stop (but even those can end safely too).
I wouldn't go so far to say that one-engine operations are perfectly safe, because all two-engine pilots prefer to have both engines operating at all times ;) but it appears that you still were in a "reasonably safe" situation.
It was helpful that you reassured your scared friends -- even if the cockpit and cabin crew didn't have a chance to say thanks, I'm sure they appreciated the cooperation of the pax, especially ones who helped ease the worries of others.
I'm a 757/767 pilot, so my systems knowledge on the 777 is limited, but the flickering of lights was most likely due to the loss of the right engine-driven generator. The load (or most of it) would be picked up initially by the other generator. Some non-essential lighting might go off during this time. Then another generator would have come on line. Usually any time a power source changes, you get some flickering. Not a big deal, but it might look a bit scary if you don't know why it's happening.
Any words of wisdom from the 777 Fleet?
[ 13 July 2001: Message edited by: McD ]
13th Jul 2001, 17:09
Thanks for the info! The question was partly also refering to the loss of Jet A1 from the engine...was there any chance it could combust outside the engine at FL370?? It just worried me slightly, with the hot engine, and fuel all around it, however I assume the oxygen density at that altitude is too low to support combustion outside of the engine? Secondly I read a windmilling engine can produce some low frequency vibration, and that it is preferable if say, ferrying an engine on the outside of the aircraft, to strap up the spools, and cover the inlets..can this be a problem at all in single engine ops??
Another question, I assume that thrust assymetry compensation on the 777 makes flying on one engine a lot easier, as the way I understand it, the rudder dynamically compensates for any thrust induced yaw..
On the 767, for example, which I beleive doesn't have TAC, during an approach with one engine using varying thrust, is it very hard to balance the rudder with the changing assymetrical thrust, whilst concentrating on so many other things? Sadly I am a very very new pilot, so no twin engine flying for me..
Thanks again for any info..
Once the jetfuel is outside the aircraft there is almost no chance of it combusting, so while a fuel leak may look scary and it can induce other problems like an imbalance or a shortage of fuel, it is not a serious as you might think. Infact, the 777 has provisions to DUMP fuel to reduce weight in order toreturn for a landing immediately after takeoff. It is possible that they had an engine failure, or knew that an engine was heading south and were already dumping fuel in preperation for landing. Generally it is preferrable to dump fuel over the water, although in theory fuel dumped from over 5000 feet should not reach the ground.
As to a single engine approach. Yes it is more difficult than normal flying, but it is a learned skill, and with practice you get quite proficient at it. Riding a bicycle is not a natural thing either, infact it is rather unstable and difficult. I am sure that when you first learned as a child you had your share of scuffed knees and elbows. But with practice you are soon whistling down the street listening to your walkman and waving to the neighbors. A long way from the slighty unsteady/sweaty progress on the the first ride without training wheels :) .
As to the question of a windmilling engine. Yes a turbine engine will windmill if they don't "plug" it. Usually when performing and engine out ferry in 3 or more engine aircraft they stick a rod down the engine to stop the rotation. This has two effects. It reduces drag, a windmilling engine has marginally more drag, so by plugging it the aircraft get better performance with the remaining 2 or 3 (depending on type). Also while the windmilling isn't dangerous, there is a problem of oil starvation. The engine isn't being properly lubricated so it increases wear and tear on the engines. That time is supposed to be logged and depending on the amount of windmilling time, certain inspections/repairs might have to be carried out. Unless the engine threw a blade, in probably won't be creating a vibration.