Hung shut-down

[TGT882]

My notes have plenty of advice about what to do if one of the ALF-502Rs' hang on start but I can't find any guidance on an engine hang on shut down. Some would advocate pulling the fire handle thus shutting the LP cock, seems to me that at the reduced fuel flow rate in this instance the time delay due to draining the fuel in the system downstream of the LP cock could enable enough of a TGT rise to damage the engine. Others might prefer to re open the HP cock get the core turning and stablised before attempting another normal shut down, this could however mean that you are spraying fuel into an already over-heated low gas flow engine. Ker-boom... good bye Job!
Any-body got any ideas?

[Cough]

First of all, how would the engine hang on shut down - No fuel = no motor!

Anyhow - Would there be any point in hitting the Overspeed test button? Im not a 146 man so I don't know the result, nor the ALF engine so the first bit may have a simple answer.

[This message has been edited by Cough (edited 15 May 2001).]

[Capt Claret]

TGT882 (-904 for 15 secs)

I've not experienced the problem but have heard that one way to cope is to momentarily re select ground idle, followed immediately and more firmly by Fuel Off.

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bottums up !

[DoctorA300]

TGT882,
If I EVER catch you NOT reengaging the starter PROMTLY when you have and internal fire, ei the senario you just described, I will personally drink a lot of beer on your credit at your local pub. Well joke aside, what you describe in your post is a rare phenomenon, especially on small jet engines, but it can happen never the less. It´s caused by an internal fire fuelled by engine oil and the only way out of it is to engage the starter and let it cranck the engine until the tgt or egt is lowered.
Brgds
DOC

[Checkboard]

Hi Claret - that method always worked for me when you saw a TGT rise on the ALF 502 just after shut down - it was fast and effective.

If that didn't work I would go for the overspeed button (which closes the fuel valve at the high pressure pump and is much faster than the handle (all this from memory now :)) which closes the fuel valve at the firewall.

Next is to complete the QRH checklist.

[Capt Claret]

G'day Checkers,

If only there was a QRH! :)

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bottums up !

[battwistingtastic]

had it happen; used overspeed shutdown-worked ok

[TGT882]

Thanks for the info....

It happened to me too, I had also heard somewhere about re-selecting ground idle so I did........
It worked a treat, only afterwards I got to thinking!! http://www.pprune.org/ubb/NonCGI/eek.gif
next time I'll try the O/S (even with N1 less than 28.5%)

:)

[maxalt]

The ALF502 will hang on shut down if the TMS is misrigged, or stuck. If the TMS motor is trimmed too far forward (or stuck) then the thrust lever at cutoff still hasn't fully signalled shutdown. Seen it happen.

[vertical speed]

I had one some years ago (have since given up on 146's and taken to 733's ) it went through 1010 degr C before finally giving up the ghost. The fault was a failed TMS -in the extended position. At that stage our airline had specifically banned pushing the os button so the problem became theirs! One thing about CFM's they always stop when asked to!

[maxalt]

1010 degrees eh? woof!
When shutting down the ALF make sure to WHACK the bugger closed. If it hangs try whacking it again. If that doesn't help try standing on the throttle and jumping up and down on it several times. Bloody useless.

[4dogs]

Clarrie,

Checker's mob do have a QRH item for it although I think it is called "engine fire on ground"

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Stay Alive,

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