Any instance of abnormal ITT increase after normal engines shutdown?
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Any instance of abnormal ITT increase after normal engines shutdown?
If anybody know the instance of abnormal ITT rising after engine shutdown, please let me know the link of the relevant report.
Or anybody know how engine parameters behave in case of abnormal ITT rising after engine shutdown, please let me know it.
Thanks!
Or anybody know how engine parameters behave in case of abnormal ITT rising after engine shutdown, please let me know it.
Thanks!
I don't think ITT rise after shutdown is abnormal, or do you mean it now rises more than it normally does? Without any air flow, the recently stopped engine parts will still be radiating heat and the ITT sensors will detect the stationary air heating up. For the next start up, you normally have to wait for the ITT to reduce below a certain value anyway, before introducing the fuel - a FADEC will monitor that automatically.
It is called a hot shutdown or afterfire. Usually caused by the throttle not being fully closed.
It is why you are supposed to monitor ITT / TOT / T4 until the N1 / NG reaches 0.
If Temp starts to rise rapidly Activate starter, confirm throttle fully closed, fuel valve off.
Nothing like watching Joe Cool close the throttle and immediately turn the battery off.
He will be unaware if he had a hot shutdown and even if he is alerted, perhaps by the strange noises emanating from the exhaust and the engineer if he is watching, by the time he gets the battery back on he may have already cooked the engine.
It is normal after a shutdown for the temp to slowly rise to perhaps 250-300 C. Especially in hot, no wind conditions. ( this is one reason to shutdown into wind to get airflow through the engine intake) . This is why we confirm on the next start that (depending on the engine ) that the temp is below 150 C before opening the throttle. Sometimes if the shutdown was short you need to do a short cooling run by energizing the starter with the throttle OFF for +- 30 seconds to “blowdown” the temp. Then wait for a couple of minutes before doing a normal start…see “Starter Limitations” in you flight manual.
We could also discuss hot starts too.
Once saw a fellow do a start, open Throttle, no light off, looked up and saw the ignitor CB was pulled out, he reached up and pushed it in…large flame and noises from the exhaust, TOT pegs, Change engine, much paperwork required. Pilot’s photo removed from the boss’s desk after a “No tea, no cookies” interview.
Hitting the starter with the throttle open on non fadec 250 series engines would produce equally startling results. ( if you did that you will not have time to do anything that will prevent a hot start. Push starter..WHUMP..TOT Pegs…game over. )
It is why you are supposed to monitor ITT / TOT / T4 until the N1 / NG reaches 0.
If Temp starts to rise rapidly Activate starter, confirm throttle fully closed, fuel valve off.
Nothing like watching Joe Cool close the throttle and immediately turn the battery off.
He will be unaware if he had a hot shutdown and even if he is alerted, perhaps by the strange noises emanating from the exhaust and the engineer if he is watching, by the time he gets the battery back on he may have already cooked the engine.
It is normal after a shutdown for the temp to slowly rise to perhaps 250-300 C. Especially in hot, no wind conditions. ( this is one reason to shutdown into wind to get airflow through the engine intake) . This is why we confirm on the next start that (depending on the engine ) that the temp is below 150 C before opening the throttle. Sometimes if the shutdown was short you need to do a short cooling run by energizing the starter with the throttle OFF for +- 30 seconds to “blowdown” the temp. Then wait for a couple of minutes before doing a normal start…see “Starter Limitations” in you flight manual.
We could also discuss hot starts too.
Once saw a fellow do a start, open Throttle, no light off, looked up and saw the ignitor CB was pulled out, he reached up and pushed it in…large flame and noises from the exhaust, TOT pegs, Change engine, much paperwork required. Pilot’s photo removed from the boss’s desk after a “No tea, no cookies” interview.
Hitting the starter with the throttle open on non fadec 250 series engines would produce equally startling results. ( if you did that you will not have time to do anything that will prevent a hot start. Push starter..WHUMP..TOT Pegs…game over. )
Last edited by albatross; 12th Jan 2023 at 17:50.
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We'd get residual fires on shutdown in CH-47's occasionally, PTIT would start to climb & you'd see smoke out of the exhaust. Just motor the affected engine for a few seconds to put it out.
There is an “Afterburner Equipped Chinook” joke there but it’s too easy a shot to take.
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