reply to post by earlywatcher
OK, earlywatcher, interesting finds.
IF it can be ascertained that was, indeed, the same airplane (and the NTSB will determine the validity of that claim) then it will be shown to be
VERY, VERY poor judgement on behalf of the OTHER pilots to continue the flight after a compressor stall.
The NTSB will investigate, as will the FAA, to see if THOSE earlier pilots noted the incident in the Airplane's LogBook. ( The Cockpit Voice
Recorder --- CVR --- only records about 30 minutes, and run continuously as long as there is power on the electrical busses). The Flight Data
Recorder --- FDR --- (or more correctly, 'Digital' FDR) can record for up to a few week's data.
As a side comment, in modern High-Bypass jet engines, what is known as a 'compressor stall', as it refers to the older Turbo-Jets, is far, far more
serious. I find it unlikely the published 'reports', which seem to be based on amateurish 'witnesses' accounts, are very accurate.
WHY is this? Because, in the High-Bypass modern engines the majority of the thrust is developed by that big fan you see in the front...consider it a
'ducted-fan' of sorts. Or, think of it as a big propellor. Anyway, in a two-stage High-Bypass engine design that big fan (the 'N1' fan) is
connected via a concentric shaft to the 'turbine', or 'hot' section, deeper in the engine. The center front of the engine includes compressor
blades to do the job of taking in air and increasing the pressure, through the various 'stages', whereby the compressed air can be introduced into
the plenum, or the 'burner', so that fuel and ignition can be introduced to produce the hot expanding gases that then are vented through the
turbine, or 'hot' section to provide the power to drive that big Fan, and produce the thrust.
The concept is simple: Suck, Squeeze, Burn, Blow.
IN FACT, except for the rotary nature of a jet engine, it isn't much different from how a car engine works. In a car, pistons in cylinders compress
the air, fuel is injected, it is sparked, and energy is expended.
A piston engine needs to translate that explosive energy, which is accomplished via cams and levers to turn a shaft....the 'crankshaft' which in
turn is connected, via the transmission to the drive-shaft of your car....etc, etc, etc. VERY inefficient!
So, really, internal combustion engines all work on the same principle, they just have different ways of conveying the energy output.
Finally, I hope this helped explain a few things....as to some 'conspiracy'??? Nah!!! No 'trial run' or any such baloney.
How do I know these things? I assure you, not from 'Google' -- but from experience. When I flew turbojets (on a B-727- a 'compressor stall' was
barely a concern, more like a hiccup, a combination of insufficient airflow during the early stages of a take-off, usually in a crosswind).
In High-Bypass Fan engines, it is far more serious....and usually results in some sort of engine damage, which by definition requires a divert to an
alternate landing site, not a "Re-Start" and continue to original destination. That's just crazy to assume that any pilot would do that!!!
I have personal experience....on A DC-10, from Paris to New York one morning...at about 22,000 feet we heard a bang, and saw the number three engine
instruments showing a failure. Since we had just left Paris, and still had two good engines, and were currently over England....hmmmm....what would
OF COURSE we diverted to London, since we knew we had Company maintenance (not contracted) there. There was NO WAY we could even consider continuing
the flight across the Atlantic, even though we still had two 'good' engines!!! BTW, the DC-10 had High-Bypass fan engines.
OK, long story short, the engine that 'blew' had JUST been overhauled, and only had about 130 hours on it....yet, a blade in the 'hot' section
appparently had a flaw that was missed, that developed into a crack, and once it let go it took out everything behind it, right out of the
Without the ability of the turbine section to properly transmit thrust to the big ole' fan, and with the imbalances that resulted, the engine shut
down. We're lucky it did, and that it didn't shake itself off of the wing....but, of course, these things happen real fast, so not much danger of
(BTW, the engine was overhauled by a 'contractor', not by the airline I worked for....so, big shout out to those who hope to limit 'outsourcing'
of maintenance procedures...)