Concorde Engine Startup

[frgthy]

I was watching the startup procedure for concorde and have a couple of questions, firstly why does the red light on the shutdown handle come on after the hp valve opens for fuel? and secondly there was a reference to a "rotating stall" which was approx 70% N2. On startup is the "rotating stall" allowed to happen to check that the monitoring instruments work, is a rotting stall detected purley by 70%N2? how is it detected in flight, is it only specific to concorde? (a detailed step by step of concorde engine startup would be appreciated)

thanks

[WOK]

When you open the HP cock several warnings are uninhibited, one of these is low oil pressure. The low oil pressure warning illuminates the "fire handle". (Which on the conc is known as an 'Engine ShutDown Handle' - ESDH - since it is used to shut the engine down in most non-normal situations, not just fires).

Like many of the apparently eccentric attributes of this machine it turns out that, contrary to how it appears during your conversion course, this isn't different to make a long course longer but to address a potential problem in a tangentially clever way. In this case - no details here, it would take 2 pages - the oil pressure light illuminates the ESDH primarily so that you shut the engine down QUICK if a certain failure mode of a HP bearing occurs.

The start procedure on the Olympus is fantastic - far more straightforward even than 744/777/A320 etc: What happens is you turn around and say "Start Engines" like it says on the checklist, there are a few clicks and grunts and all four just wind up! Sometimes two at a time! I can't imagine why there are four pages in the manual detailing it....

Every aeroplane should have a flight engineer.

Oh yeah, rotating stall. Is a possible airflow condition following start in which the first stage (possibly more?) compressor is effectively stalled, upsetting airflow through the 'fan' but not enough to cause a surge. I believe that it is possible to induce flutter or acoustic damage in the N1 stage. It is difficult to detect rotating stall so to eliminate it the start sequence should accelerate the engine to c72% N1 before rolling back to c70%. This takes the fan out of the regime where RS is possible.

If this isn't observed the TCU for that engine is set to the other lane and the throttle up/down done manually.

Just a little foible of the engine, never a drama.

I'll stop now, this could go on and on. :)

PS How/where on earth did you spot all this going on? 10/10 for observation.

[the_fat_maintroller]

The Red Fire Handle is triggered by the low oil pressure warning, an interesting part of the QRH, It has caught at least one station engineer out, Fixed the oil leak.....ahhh now how do I get a fire bottle and squibs to India..if only I had an APU to rob.
As for the rotating stall, I would have to dig out the engine notes.
Surprised you didn't question the de-bow starts though!

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Yeap, yor right Captain, it is broken..I'll get you an engineer

[frgthy]

Thanks for your replies all a lot clearer, however if there happens to be a concorde FE out there a detailed step by step of the engine startup procedure would be appreciated