B737-800 air carrier crew reported high engine EGT temperatures during climb out during high temperature conditions. The engine temperatures returned to normal after climb thrust was selected and the flight continued to the destination.
Synopsis
B737-800 air carrier crew reported high engine EGT temperatures during climb out during high temperature conditions. The engine temperatures returned to normal after climb thrust was selected and the flight continued to the destination.
Narrative
Flight was planned very close to max takeoff weight limited by ZZZ temperature/runway/climb limits. Initial performance data was 26K improved flap 5. We noticed that the flaps one numbers seemed to offer a slight climb advantage. I contacted Dispatch and asked for a 26K improved flaps 1 so we could compare. Dispatch sent a 27K bump flaps 1 (bleeds on IIRC). I contacted the Dispatcher and asked if he meant to send the 27K bump. He verified that he did and that it was common out of ZZZ in the summer. We configured the aircraft for 27K; flaps 1; bleeds off; APU on. Departure roll/liftoff was normal. Shortly after gear retraction; the First Officer (FO) announced high EGTs on both engines. I verified both were red. I am familiar with the allowance to disconnect the auto throttle (AT) and trim back the hot engine; however the case of both engines being hot and flying into rising terrain; the thought of pulling back both at the same time gave me pause to consider how this might affect out climb with the larger percentage of power reduction. I spent a couple seconds watching our climb (we had a good rate). I then decided that we could probably reduce the power slightly on both engines without issue as long as both kept running. I faced another issue as I was pilot flying (PF) and the air was quite turbulent I was working to keep the aircraft on the proper flight path and I was not sure I would be able to accurately fly and trim the engines. I decided to try to use the pilot not flying (PNF) to trim the engines. As I was getting ready to verbalize this; I noticed that the aircraft was reaching acceleration height and the AT pulled the power pack; returning the temps to normal. Enroute a logbook entry was made for each engine overtemp on takeoff. On landing; both engine EGT were boxed and an entry was made for each. A subsequent review of Maintenance actions appears to show both engines will need to be removed for inspection.Cause: As far as I am aware; we had a valid performance data for the conditions at hand. The aircraft was configured per the performance data. The engine should have made rated power without an EGT exceedance; but did not. I would assume that if this is the case; then it was an engine wear issue.A case could be made for using the 26K performance data. The engines might/might not have exceeded temp limits; although not as much I would assume. I did consider asking for a new 26K after we got our close out but decided to go with 27K as it had better margins and I did not want to task load the FO any more than I already had. As the airplane had been setup at the gate; changing numbers again on the taxi seemed an opportunity to introduce an error. We had good performance data/close out/and weather; so I went with 27K.I could have been quicker on the power reduction; however this was a novel situation. I was comfortable with the thought of a slight thrust reduction on one engine at low altitude; but had never consider what the implication of reducing power on *both* would be. I did not want a scenario where a reduction caused a climb/clearance issue. How far back should one pull the power? What if one quits on power reduction and the remaining engine is at an intermediate lower power setting? Will we make our climb? This event would make a good training spot. I am sure operations could develop data to show what the effect of a reduction on one or both engines would have at various places in the climb and how it affect ones climb performance. In this situation; task sharing; and having the PNF reduce the power is probably the best option; and could easily be practiced in the simulator.
Second reporter narrative
The Captain and Dispatcher deliberated on weight and temperature for take off and the Dispatcher issued 27K bump performance data off of XXR in ZZZ. The Captain again called the Dispatcher and confirmed that the 27K bump was approved and they agreed upon the use. We performed a bleeds off takeoff and after liftoff; I noticed the EGTs go red and informed the Captain whom was the pilot flying. At a safe altitude; the Captain reduced the thrust on the engines and the EGTs returned to the normal range. We noticed no other abnormalities and continued the flight. Cause: It was around 40c in ZZZ and we were heavy. I don't currently have any recommendations on mitigating the risk.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.