A B737-700 leading edge flap actuator failed at V1 so the takeoff continued. After trouble shooting; the flight returned to the departure airport where an incorrect V speed was flown; putting the aircraft in the min maneuver range.
Synopsis
A B737-700 leading edge flap actuator failed at V1 so the takeoff continued. After trouble shooting; the flight returned to the departure airport where an incorrect V speed was flown; putting the aircraft in the min maneuver range.
Narrative
Right at V1 we got the LE flap Transit light. Rotation was initiated and we got the Configuration Warning horn and a stick shaker for five seconds. Flaps 1 was retracted on schedule. Looking at the LED Annunciator showed all LE devices in Amber Transit. The view from flight deck showed LE devices extended both sides. Started reviewing QRH Flaps; Leading Edge: LE Flaps Transit. Aircraft was flown at 230 knots. Above 10;000'; we advised ATC of warning light and that no emergency was being declared. Called and asked Operations for a patch to Dispatch. Started talking to flight attendants; passengers; and Company Pilot riding in cabin; who told me LE devices were extended. Went back to the QRH and now was talking to Dispatch. Were going through about FL 200 and heard pop sound. (Later we found out it was LE Actuator #4 failing.) Dispatch got back to us and told us to go back to the departure airport for Passenger consideration. We ask for vectors back. Called Flight Attendants and Pilot in cabin for any more information. Pilot told me of hydraulic fluid flowing over wing. Hydraulic quantities were good. The plane was flying well. Advised passengers of return to the departure airport and estimated time of arrival. Went back to QRH. Reviewed landing configuration and we talked about it; but now I had to get ATIS and landing performance information. Got all that out of the way but forget to execute it in FMC! On final visual XXL; flaps 15+5 not 15+15. Speed was in minimum maneuvering band. Still didn't realize our mistake. I went to the performance reference and selected flaps more than 1 less than 15 speeds and selected flaps 10 with max autobrake. Rest of approach and landing were uneventful. Checked brake cooling time of 30 minutes. At gate; met with Maintenance and called Chief Pilot on Call. Logbook writeup was made. Went on to next flight to our destination.
Second reporter narrative
After the flaps were raised; the LE Flaps Transit light remained illuminated and slats 1 and 8 could be seen from the cockpit as partially extended. I requested radar vectors back to [departure airport]. We continued the QRH with the During Configuration for Landing (Trailing Edge Flaps Extended) portion of the checklist. The performance data was reviewed and VREF/Target speeds were set in the FMC. However; while flying I missed the PM reading Note L stating the speed would be VREF 15 + 15. The speeds set in the FMC were VREF 15 only. I feel that hand-flying the aircraft took some of my attention away from following what the PM was reviewing in the QRH. Since the autopilot was off; I could have had the PM fly the aircraft and also reviewed the procedure while we had a couple of minutes while being radar vectored back to the airport. I think we should have stayed closer to [the departure airport] while we worked the QRH and made decisions. I think a quick review of the landing portion of the QRH on final approach would have led us to our error. Instead we chose a safe but different option. Since the Descent Checklist is from the QRH another quick review of the correct landing configuration by the PM may have caught our failure to set VREF 15 + 15.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.