Milan320 From Canada, joined Jan 2005, 868 posts, RR: 12 Posted (9 years 1 month 3 weeks 2 days 14 hours ago) and read 3685 times:
Perhaps this seems like a really stupid question, but if during flight, say the right engine flamed out, would the PTU pump spring into action to maintain hydraulic pressure and in turn produce the same "barking" sound that one hears during engine start-up? (long sentence, I know ).
NKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 5
Reply 1, posted (9 years 1 month 3 weeks 2 days 9 hours ago) and read 3643 times:
Could be, if...... If the right engine driven yellow system hyd pump was not producing output ( let's say the right engine's pump failed, not the engine....to take windmilling out of the equation ) and IF the electric yellow system pump either failed or was selected off....then yes, the green system pump ( left engine ) would pressurize the yellow system via the PTU.
SlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 69
Reply 2, posted (9 years 1 month 3 weeks 2 days 8 hours ago) and read 3633 times:
Had this situation not too long ago. High downwind for a visual approach and the left engine flamed out. We tried a restart, with no luck. We briefed the flight attendants but elected not to tell the passengers. Landing was uneventful and felt just like the simulator. Some passengers noticed the fire trucks following us to the gate. Some did not. No one asked about them.
One passenger asked a flight attendant after we got to the gate about the PTU operating for the last few minutes of the flight. She told him the truth and he was okay with it. Must have been a non-rev.
Anyway, the green hydraulic system is gets primary power from an engine-driven pump on the number 1 engine which was windmilling at rather low speed. When the pressure differential hit 500 PSI the PTU was signalled to run and frankly I never noticed.
Anyway that was my 5th engine failure. Two in single-engine, two in four-engine and that was the first in a two-engine plane. Might think of it as my only time in a single engine jet.
[Edited 2005-01-15 01:47:30]
[Edited 2005-01-15 01:48:53]
Happiness is not seeing another trite Ste. Maarten photo all week long.