Flying Home Commericially Tonite...

.... had a front row seat (actully it was an exit row window seat...) for a
compressor stall on an America West Airbus while departing Detroit enroute
home to Phoenix.

Just after liftoff we heard/felt a moderate "bang" and I glimsed some flame
out the back of the left engine just about the time the gear was in transit.
Captain came on the I/C and said it was due to wake turbulence from the
Northwest Airlines aircraft that departed ahead of us.

Flight continued to Phoenix without any further issues.

Pretty interesting when you momentarilly take "suck" out of the "Suck ...
Squeeze ... Bang ... Blow" chain.

Am I correct in thinking that disrupting the airflow into a turbofan engine
sets up a momentarilly over-rich mixture (hence the visible flame?)

Jay Beckman
PP-ASEL
AZ Cloudbusters
Chandler, AZ

"Jay Beckman" wrote in message
news:08tsf.9585$xF6.1071@fed1read01...
... had a front row seat (actully it was an exit row window seat...) for a
compressor stall on an America West Airbus while departing Detroit enroute
home to Phoenix.

Just after liftoff we heard/felt a moderate "bang" and I glimsed some
flame out the back of the left engine just about the time the gear was in
transit. Captain came on the I/C and said it was due to wake turbulence
from the Northwest Airlines aircraft that departed ahead of us.

Did you feel some turbulance?


Flight continued to Phoenix without any further issues.

Pretty interesting when you momentarilly take "suck" out of the "Suck ...
Squeeze ... Bang ... Blow" chain.

Ummm...that doesn't apply to turbines....at least not as a discrete
sequence.


Am I correct in thinking that disrupting the airflow into a turbofan
engine sets up a momentarilly over-rich mixture (hence the visible flame?)

MTL.

Matt Barrow wrote:
"Jay Beckman" wrote in message
news:08tsf.9585$xF6.1071@fed1read01...

... had a front row seat (actully it was an exit row window seat...) for a
compressor stall on an America West Airbus while departing Detroit enroute
home to Phoenix.

Just after liftoff we heard/felt a moderate "bang" and I glimsed some
flame out the back of the left engine just about the time the gear was in
transit. Captain came on the I/C and said it was due to wake turbulence
from the Northwest Airlines aircraft that departed ahead of us.


Jet engines do sort of have the suck/squeeze/bang/blow but it's all a
continuous action. Check out the link below for a slightly more
detailed view. Compressor stalls can be nasty as pressurized combustion
gasses going the wrong way can in some instances damage the engine.

I don't think it's so much of an over rich mixture causing the problem
as it is the flames going the wrong way or burning in such a way that
they aren't producing a lot of air pressure to spin the turbine at the
outlet end of the engine.

http://www.grc.nasa.gov/WWW/K-12/air...bpar/ente.html

"Robert Chambers" wrote in message
newsCxsf.4558

Compressor stalls can be nasty as pressurized combustion gasses going the
wrong way can in some instances damage the engine.

Here is a good question, for someone has actually stalled a civilian
compressor. Do you have to log compressor stalls, or do anything extra,
after stalling one?
--
Jim in NC

"Morgans" wrote

Here is a good question, for someone has actually stalled a
civilian compressor. Do you have to log compressor stalls, or
do anything extra, after stalling one?

Used to happen all the time in the old B-707s due to "sticky"
surge bleed valves between the N1 and N2 compressor sections.
No write-ups due to compressor stalls, but we might write-up
the surge bleed valve. In the JT-3D engine, it was not a matter
of not enough air, but rather too much air fed from the N1
compressor stage to the N2 stage.

Bob Moore

"Morgans" wrote in message
Here is a good question, for someone has actually stalled a civilian
compressor. Do you have to log compressor stalls, or do anything extra,
after stalling one?

The center engine on the B-727 was prone to compressor stalls with strong
crosswinds during the initial take-off roll. According to our manuals, the
engine was to be removed after the second event. We were usually too busy
during take-off to write it.

D.

"Jay Beckman" wrote in message
news:08tsf.9585$xF6.1071@fed1read01...
... had a front row seat (actully it was an exit row window seat...) for a
compressor stall on an America West Airbus while departing Detroit enroute
home to Phoenix.

Just after liftoff we heard/felt a moderate "bang" and I glimsed some
flame out the back of the left engine just about the time the gear was in
transit. Captain came on the I/C and said it was due to wake turbulence
from the Northwest Airlines aircraft that departed ahead of us.

Flight continued to Phoenix without any further issues.

Good guess, as to the rich. No air was going through, but I'll bet that
fuel was.

I was on a flight that must have been the first landing of the first
captain's sisters kid, who had never landed anything before. It was
overcorrected all of the way down, landed long, and when he put the thrust
reversers up and gunned it, it stalled, not once, but twice.

My only experience with them, however.
--
Jim in NC

A few years ago, before I started flying, I was on an American flight
out of Houston with a pretty good crosswind ripping across the runway.
I was seated near the back of the plane. A couple of seconds after
takeoff we heard a VERY loud bang, the left wing dipped momentarily,
and we continued on...

About 20 minutes later the captain came on and explained they had a
compression stall due to, he said, to the wind blowing across the
engine. He apologized for waiting so long to explain it, but he said
he and the crew were busy going through the manual for the restart
procedure.

Not being a pilot at the time, I remember thinking that maybe he should
have read the manual BEFORE flying the plane :-)

If it's really true that the crosswind caused the compression stall, I
wonder why we don't hear about a double stall very often. Theoretically, the
wind can be strong enough to affect both engines, no?

Marco Leon

"Wiz" wrote in message
oups.com...
A few years ago, before I started flying, I was on an American flight
out of Houston with a pretty good crosswind ripping across the runway.
I was seated near the back of the plane. A couple of seconds after
takeoff we heard a VERY loud bang, the left wing dipped momentarily,
and we continued on...

About 20 minutes later the captain came on and explained they had a
compression stall due to, he said, to the wind blowing across the
engine. He apologized for waiting so long to explain it, but he said
he and the crew were busy going through the manual for the restart
procedure.

Not being a pilot at the time, I remember thinking that maybe he should
have read the manual BEFORE flying the plane :-)




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Marco:

Don't know if it's true or not -- just what the pilot said...

Cheers,
Wiz


Marco Leon (at) wrote:
If it's really true that the crosswind caused the compression stall, I
wonder why we don't hear about a double stall very often. Theoretically, the
wind can be strong enough to affect both engines, no?