B737-700
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 200; Flight Crew Type 3800
Troubleshooting; Workload
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; Flight Crew Overcame Equipment Problem; Flight Crew Landed in Emergency Condition; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Procedure
Arriving at the aircraft and checking the logbook; I noticed that the last crew had written that the Takeoff Configuration light and horn activated on takeoff (speed of activation was not noted). I surmised that the crew rejected the takeoff and subsequently swapped out of the aircraft after returning to the gate and the aircraft was not flown afterwards. The corrective action was a check of the Takeoff Configuration Warning System with no faults noted. Since nothing was actually corrected; the Captain and I discussed the possibility of it activating again on our takeoff. We pushed late due to an unrelated finding of damage in the floor of the Forward Cargo Bin C. The bin was deferred and bags transferred to the aft bin. We were relatively full on this flight and our V1/VR speeds for Flaps 1 on Runway XXR were 125/135. The engine start and taxi out were uneventful with the throttle burst yielding no takeoff warning. On the takeoff roll at approximately 130 knot (5 knot after V1) the takeoff warning horn and light activated. We elected to continue the takeoff. The initial climb was normal and we discussed that we would be writing this up in ZZZ1. The Captain called for 'flaps up' at the appropriate speed and I moved the flap lever to UP. We had a few distractions from ATC due to hold-down altitude that was cancelled. Before I moved the landing gear handle to OFF; I checked the flap indicator and noticed that the flaps were still at 1 with the LE FLAP EXT green light illuminated. After confirming that the flap handle was up; I told the Captain the issue and that we need to keep our airspeed below 250 kts. and level off to handle the problem.After notifying ATC that we would need to level off; they gave us vectors for terrain while we ran the QRH for Trailing Edge Flap Disagree. Since the QRH doesn't really address the disagreement when attempting to RETRACT the flaps and only deals with setting the flaps for landing; we turned our attention to coordinating the air return. Dispatch was advised of the return as well as Station Ops in ZZZ. Our current gross weight was a little over 130;000 pounds so we extended the gear to add drag and burn off excess fuel for landing. The F/As (Flight Attendants) and passengers were notified of the return. Since this was a flight control issue; we [received priority handling] and notified ATC that we were requesting [Runway] XYL but would need time to reduce our landing weight to 128;000 pounds. We felt this was the safe option as time was not an issue. We then ran the QRH; ran the performance calculation for the Trailing Edge Flap Disagree QRH; and then the brake cooling module. The flaps extended normally with the Alternate Flap system to 15 degrees. The only slight issue was although I read the section directing the flap lever to be moved to the final flap position (15); we were sidetracked by discussing slowing during the extension and this was not done until after the QRH was completed. This allowed us to see our Flaps 15 maneuvering speed. After the delay vectors were complete and we were below the maximum landing weight; we made an uneventful landing on [Runway] XYL. Brake cooling allowed us to take right to the gate and the ARFF (Airport Rescue and Fire Fighting) trucks followed. No other issues occurred. We swapped into another aircraft and continued the pairing.
The aircraft was an originator. The previous day a takeoff had been rejected because of a spurious Takeoff Config Warning and the maintenance resolution was no faults noted. The F/O (First Officer) and I discussed possible reasons for a false warning lasting a few seconds; which refreshed our memories of the warning system and thankfully prepared us for a repeat occurrence. We pushed late due to an unrelated finding of damage in the floor of the forward cargo bin. The bin was deferred and bags transferred to the aft bin. On takeoff; approximately two seconds after the F/O's V1 call; the configuration light illuminated and the warning horn sounded. The F/O called VR; and we lifted off. The light went out and the horn stopped about the time the wheels left the ground. The F/O's performance and adhering to procedure during this event was flawless; which combined with our earlier discussion allowed the situation to be handled easily. We briefly mentioned writing the issue up again in ZZZ1. I called for Flaps Up; from their takeoff '1' setting. F/O moved the flap lever to Up; and then moments later told me the flaps didn't go up; and instructed me not to go over 250 [kts.]. We were still at about 200 knots; so no airspeed issues. I told F/O to tell ATC we needed to level off and maintain low airspeed. Initially we told ATC we would follow the SID and get back to them. ATC gave us a terrain clearance altitude. We confirmed the flaps were not up. I called for the QRH and we agreed that 'Flap Disagree' was the appropriate checklist. The checklist starts off by saying 'to prepare for landing' so we paused the checklist; agreed we were not going to ZZZ1 with flaps out; and I messaged Dispatch we were returning to ZZZ; told ATC; and received clearance to return to ZZZ. I notified the F/A (Flight Attendants) and told the passengers we were returning to ZZZ. We ran the QRH for Flaps Disagree; the procedure went mostly uneventfully. We were at 130;000 pounds; so we took delaying vectors to burn fuel to 128;000 [lbs.]. We checked the brake cooling for Autobrake 3; no issues. We did [receive priority handling]. We landed Flaps 15 and taxied to the gate. Positive takeaways. The CQT training from (year)?; (year)? that emphasized flap malfunctions prepared us well to handle the stuck flaps. Negative takeaways. The QRH for Flap Disagree was obviously written with a failure occurring during approach in mind. For our situation of failure on takeoff; the procedure kept us with the flap handle up until we had returned to ZZZ and were preparing to land; which meant we had flaps out; but no maneuvering speed. We know that Flaps 1 speed is 180 knots approximately; but it would have been one more item in our favor if we had moved the flap handle to match the flaps to give us the normal sight picture on the displays. While we were extending the flaps with the alternate switch; between watching the flap gauge and calls from ATC; we momentarily missed the instruction in the QRH to move the flap handle with the flap movement. We followed proper flap speeds as flaps were extending; but that that was because of our experience; not the display. The QRH should have the instruction to move flap handle with flaps before the actual instruction to move the flaps so that crews can discuss the handle in advance. We ran the brake cooling for Autobrake 3; and then tried to run again for Autobrake 2. The brake cooling module did not work the second time. We recalled a recent (Company communication piece) about Dispatch doing something to mess up performance calculation results; which could be rectified by requesting landing data again; but that did not work. Something in the performance calculations needs to be corrected so that brake cooling can be run more than once. Brake cooling was not an issue; even with Autobrake 3; so this was a small nuisance. Based on passenger comments; F/As did a great job. F/O's performance was excellent; our teamwork together allowed the situation to be handled easily.
Flight Crew reported a repeat failure of the Take Off Warning System and a failure of trailing edge flaps to retract caused an Air Tun Back and a precautionary emergency landing.