EGT OVERLIMIT at T/O: continue flight?
Join Date: Feb 2008
Location: Wingham NSW Australia
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Overtemp at T/O thrust (or any other time)
Until the post by JazzyKex nobody seems to have mentioned other engine parameters. Personally experienced scenario: T/O at close to MTOW, Max Thrust required, B747-200. Just before first thrust reduction noted No 2 EGT climbing past Max Allowable, no other parameter following. Reduced thrust to bring EGT below Max permissible. Cycled No 2 EGT indicator CB, EGT indication immediately reduced by approx 100 degrees C. Flight was to be of approximately 7 hours duration. Full Pax load and approx 125 tonnes of fuel. Thrust reset & EGT normal, discussed my observations and actions with Captain. A consensus of ACTUAL problem reached, i.e an indication fault rather than an actual overtemp. Decision made to continue and monitor. No further abnormal indication. EGT indicator changed during tech stop, oncoming Crew briefed. Aircraft continued on next sector with no abnormal indication until well established in cruise. F/E did exactly as I had i.e. cycled No 2 EGT CB, indications returned to normal. During next turn-around a "ballast resistor" in the EGT indication amplifier was found faulty, replaced and no further abnormal indication noted on subsequent flights. Moral of this story, "More than one parameter will usually be abnormal so indication needs to be cross referenced with others to determine REAL problem". Common sense, experience and system knowledge was used in this instance to enable the flight to continue in safety. The rule "Hasten slowly", I think, was shown to be good advice in this instance.
Last edited by Old Fella; 24th Jan 2011 at 09:02.
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Yes, we have a chart in our log for time v/s temp. If at base you may return depending on the calculated temp/time. It is important to determine if your exceenence requires a detailed inspection or engine overhaul.
Time v/s temp should be a calculation availible to you.
Time v/s temp should be a calculation availible to you.
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Old Fella: Good show sorting out that EGT indication problem.
As a stateside product support engineer, I was once confronted with a customer's engine with several percent high fuel flow. After a telex or two over a 10000 km distance, we deduced the actual fuel burn did not match the excess shown on the FF gage.
Then I found there were two different FF transmitters, with different calibration points (low vs high FF). They looked identical, same basic p/n, different dash number. Swapped the transmitter for the correct item, customer satisfied.
While this problem was quite benign, the Tuninter ATR72 crew had a related problem that was not so minor.
As a stateside product support engineer, I was once confronted with a customer's engine with several percent high fuel flow. After a telex or two over a 10000 km distance, we deduced the actual fuel burn did not match the excess shown on the FF gage.
Then I found there were two different FF transmitters, with different calibration points (low vs high FF). They looked identical, same basic p/n, different dash number. Swapped the transmitter for the correct item, customer satisfied.
While this problem was quite benign, the Tuninter ATR72 crew had a related problem that was not so minor.
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Subtask 72-00-00-290-053
