2024-08 · NASA ASRS report 2154169
B737 flight crew reported the master caution and number one engine overheat lights illuminated during departure climb. Flight crew returned to departure airport and landed safely.
Flight XXXX ZZZ-ZZZ1 Probationary FO; so my assessment was that it would be safer to give us more time at the airplane before departure. So we coordinated the night prior to meet at the airplane in lieu of operations. My commute in to the gate was delayed. There was a longer than usual delay waiting for the bus from the employee lot. Known crew member resulted in a random selection. During this I noticed a last minute aircraft swap and resultant gate change. That information changed my transit to the gate and that transit on the 'people mover' was crowded and slower than usual. At the gate the manager had to brief me on approx 5 LEOs (Law Enforcement Officers). Once I got down to the airplane; two flight attendants advised me of 2 different write up's that needed to be addressed before departure (flight attendant jumpseat cushion and 5 inop direct TV screens). A third flight attendant advised me via inter phone as I sat down that the lav needed to be serviced. It was then that I started to try to download the new release for the new airplane and read the MEL. We were already boarding. Our normal preflight was then disrupted by approx 5 LEOs (Law Enforcement Officers) coming in succession to the cockpit to check in.We put in chat and called to ops for lav service. The FO had already called maintenance for the jumpseat issue before my arrival. Maintenance was on the scene quickly and above average. They very quickly addressed all of new issues and then; because they happened to be there; discussed the MEL for ENG 1 loop B. We all looked at the fire panel and noted that despite the MEL; BOTH was selected on ENG 1. With review of the MEL and with maintenance concurrence; I selected loop A; it and tested successfully. The maintenance rep had a new maintenance release for us immediately as the write up's were addressed.Additionally; during all this; the ground crew was attempting to connect unsuccessfully using multiple ground to cockpit alerts and use of hand signals to establish comms. The lav service also required multiple calls to the back and calls to ops to see if it had been accomplished.With numerous interruptions we completed our pre-flight briefings. Ground headset communication continued to be a problem with many interruptions. At one point somebody signaled the FO to release brakes with hand signals; counter to the ground communications that had just finally been establish.The primary threat briefed was that this was a very busy push; and mitigation was to slow everything down; which we did. We ended up blocked out 1 minute late. The normal runway XX was closed resulting in a high density taxi environment and wait time. On departure we were kept level multiple times below 10k for long periods on vectors.Above 10k; things resumed to normal. Not long after we notice a solid master caution. The system annunciator was not illuminated. After searching quickly for the cause of the master caution unsuccessfully; we depressed the recall. The OVHT/DET (Overheat Detector) was then illuminated. Looking at the fire panel the Engine Overheat light was then observed. We then actioned the immediate action items. On reaching idle the light remained illuminated. By this point we had slowed our ascent; transitioned above 18; and had to start interacting with ATC for a level off and return [requested priority handling]. By the time we got to the QRC/QRH and started to go to the engine shutdown checklist; the light extinguished. QRH directs that the engine be run at a thrust level that does not illuminate the overheat light.QRH complete; we transferred controls to the FO. I sent an ACARS to dispatch; gave the flight attendants the brief stating that this would be a normal landing and not anticipating an evacuation. I asked that one of them to visually check the left engine and call back only see if they saw anything unusual. I then made a PA.With discussion we elected to keep the engine running at idle and use it for landing; while briefing actions that we would take if the light reilluminated and forced an engine shutdown. We reviewed landing procedures; including engine failure/shutdown on final.After reprogramming the FMC I attempted to get landing data for ZZZ for an overweight landing. It kept returning an error code regarding being the correct aircraft. I'm not sure if this was normal or I was doing something incorrect. In the process of reviewing single engine landing I looked up the landing distance in the non normal configuration chart for flaps 15; saw that it was more than adequate for planned runway XYL; selected max auto brake and continued.My formal brief for the descent and approach was disjointed and not very comprehensive; briefing things more as they came up on the arrival. That was an error from the threat of constant distractions.The support from the FO was honestly outstanding and far above his part 121 experience. He brought up several pertinent issues at appropriate times; had a calm; helpful demeanor; flew the airplane well; and was absolutely methodical with checklists and procedure.During the arrival we transferred controls back to the left seat. It was then that I realized I had not actually looked at the overweight considerations in the FM and asked my FO to quickly review those to make sure we had not missed anything. While the FM discussion on overweight landings is good; it is not suited to a return environment. A QRH or supplementary procedure with bullet points would be much more useful than a several paragraphs of a long discussion.The small difference between on speed and max flap speed was alarming to see. Even a minor gust could have resulted in flap load relief and mandated a go around below 500'; and bringing power up to go around power on an engine that could go into overheat would have been uncomfortable. I had elected to make the approach at flaps 40 with the idea that we would be fast on approach and I wanted to be as slow as possible. I also thought that the decrease in approach speed would be commiserate with the difference in maximum flap speeds. I realize now that was incorrect and flaps 30 would have been more appropriate.The landing was uneventful. We taxied clear of the runway towards the emergency vehicles and stopped to allow them to check us. Coordination with ATC and fire service was seamless and expeditious. I made an announcement to the passengers that the service vehicles were quickly checking on us out of an abundance of caution. After they checked the engine and the brakes; the overheat light having never reilluminated; we elected taxi back to the gate. I kept both engines running because we were heavy; could shut the engine down at any time we got the light; and had emergency vehicles following us.After shutdown at the gate and parking checklist; I made another announcement apologizing for the inconvenience; and advised everybody to check their apps and talk with the Customer Service Representative regarding their amended travel plans. Me and the FO quickly debriefed but as soon as we opened the door maintenance were there and needed their debrief.Because I was busy as well I quickly wrote up the engine overheat and overweight landing without any detail because I assumed that I would have an extensive verbal debrief. As well it would have taken me a very long time to type out all the details on the ACARs. Maintenance expressed some displeasure with this. If I had to do it over again I would have waited to type the writeups with maintenance beside me so the appropriate details would be in the original writeup.Chief Pilot's office support was great. We were met at the gate by the Chief Pilot's office representative. He put us at ease; helped us with a human factor survey; support and with our schedules; etc.Following all that I met the flight attendants in the back and had an extensive debrief. I had intermittently monitored their PA's and knew they had donea great job despite all the stress.As we were leaving the flight deck finally; the FO noticed that the engine overheat light had reilluminated with the engine shut down. I called maintenance to update that fact.I made an announcement to the passengers at the gate; called the Chief Pilot; and went to the Chief Pilot's office to further debrief with the Chief Pilot's office representative.
I arrived at the aircraft right at our scheduled report time; following a gate change and aircraft swap. I boarded and immediately started pre-flight procedures. I was quickly interrupted by one of the flight attendants who asked if I could contact maintenance about an issue with their forward jumpseat. I made an entry through ACARS and contacted hub maintenance verbally. I then stepped out to do the walk-around. Upon my return to the cockpit I resumed pre-flight; and downloaded release 2 for the aircraft change. At this time I also read the maintenance release and noticed that fire detection loop B for ENG 1 was inoperative and deferred; and we were to operate on loop A. I was then interrupted again by another flight attendant informing me that 5 of the direct tv screens in the back were inoperative. I told her maintenance was already on the way and would take a look at those as well. Shortly thereafter the CA arrived. As we proceeded through our normal pre-flight procedures and brief; we were interrupted several more times by LEOs (Law Enforcement Officers) boarding; the maintenance tech arriving; and another issue the flight attendants had identified (aft lav requiring service). When the maintenance tech arrived we went through the maintenance release write-up with him; confirming that it was in fact the B loop deferred. We confirmed this because when arriving at the aircraft the selector switch was in 'both'; not 'A' as it should have been. It then tested without issue.Once our new maintenance release was produced; we tried to get through our pilot brief. We were interrupted several times by the ground crew headset trying to connect without success. We also called ops several times to get confirmation of the aft lav service.We finally completed our brief and prepared to push; but ran into more issues with the ground crew headset. At one point I was given a hang signal asking if brakes were released despite the CA having verbally advised that we were not ready for brake release. These headset issues caused further delays with our push.We finally pushed back successfully and got taxi instructions to runway XYC; as the usual XX was closed. This caused brief departure delays due to our sequence. During this time the CA and I both remarked how that morning had several more interruptions and issues than usual. Although we managed them and identified the threat; they had caused some distraction. We mitigated with a slow taxi on both engines to regain control of pacing.Our takeoff and initial climb was uneventful. We were leveled off several times at low altitudes for traffic separation; and were given vectors. We eventually were given a higher climb and passed through 10;000 without issue. Shortly thereafter we noticed a master caution but without any illuminations on the recall panel. This led to a momentary delay as we searched for the cause of the master caution. We eventually identified the cause as a number 1 engine overheat light. We actioned the immediate action steps; called for and ran the QRC/QRH; and resultant reduced thrust on the left engine. The overheat light remained illuminated and we were discussing shutting the engine down when the light extinguished. We then ran the engine at idle thrust. We then [requested priority handling] and began a descent. The CA then gave me the controls to fly while he communicated with dispatch; the FAs; and passengers. I continued flying and started getting us vectors back to ZZZ. He also got landing data and began setting up for the approach back to XYL. During this time we discussed the plan to use the left engine for landing; and our plan if the overheat light came back on during the approach. The CA set brakes max; but we both agreed we had plenty of runway to stop the aircraft regardless. During this time our workload and stress levels increased and we became slightly task saturated and distracted with ATC communication; flight path management; briefing; andensuring we were not missing any steps. The landing data that the CA sent for returned an error; so we sent for it again. It came back with an error again; so he ran the non-normal landing distance and we reaffirmed that we had adequate stopping distance. At this point I transferred control of the aircraft back to the CA for him to fly the approach and landing. We intercepted the localizer and glide slope and proceeded with the approach. At this point the CA asked me to reference the overweight landing criteria to make sure we had not missed anything. It took me quite some time to find the correct section as there was no quick reference or supplementary procedure quick link. We abandoned the search as we were descending on final and decided landing the airplane safely with both our focus on flight path was more important. It was an oversight as we became task saturated.We landed safely and taxied clear of the runway before coming to a stop. We then contacted the fire marshals and asked them to check the left engine. They said they saw no abnormality so we decided to taxi in on both engines. We returned to the gate uneventfully and shut down. The CA made a PA apologizing for the inconvenience and explaining the situation and what could be expected next for follow-on passenger transport. We then began our debrief before being interrupted by maintenance. We discussed our experience with them; and subsequently with the Chief Pilot's office representative who was waiting at the gate for us. He was extremely supportive and put us both at ease. We debriefed human factors with him; and then got up to leave the aircraft and head to the Chief Pilot's office. It was at this point that I noticed the overheat light had returned with both engines shut down. We confirmed that maintenance was not working on the aircraft yet; and called them to let them know. We then left and went to the Chief Pilot's office to continue our debrief and notify the Chief Pilot.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.
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