B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 175
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Flight Crew FLC complied w / Automation / Advisory; General Maintenance Action
Aircraft
On departure; upon flap retraction the LE Flaps Transit light remained illuminated. We then noted the number two leading edge flap transit segment illuminated on the overhead panel. We followed the Quick Reference Handbook (QRH) procedures; and temporarily leveled at FL190 so as to remain beneath the FL200 flap extension limitation. As directed by the QRH; we recycled the flaps from Up to 1; and then back to Up position. The fault remained. Following QRH procedures we were restricted to 300 knots/.65 Mach. After contacting the Company; it was decided by Dispatch and Maintenance (MX) Control that it was safe to continue. We concurred with their decision; as there was no other indication of a problem. No adverse pitching or rolling motion detected; no buffeting or any other unusual sounds were noted. Both the Captain and I assumed it was a faulty proximity sensor. We notified ATC of the issue and changed our cruise altitude to FL350 and our cruise speed was edited to .65 Mach. Upon checking-in with Approach; we were issued Runway XXR. I requested Runway XY because it was the longest runway and we were planning on a flaps 15 landing with increased approach speeds. Approach asked if we needed assistance or equipment and I declined; since all other indications were normal and there was no adverse flight control feel noticed. We were assigned Runway XY and landed without incident. Taxiing in; we retracted the flaps as we normally do; and all lights extinguished. So when MX arrived at the aircraft there were no unusual indications at all. MX lowered the flaps at the gate and discovered the missing number two Kruger bullnose inboard bolt. There are two main bolts (one now missing) and one actuator linkage; and so the flap segment was hanging down from those attachment points. The MX Technicians inspected the flap segment and surrounding areas for damage; and found none. The flap segment was reinstalled with a new bolt and a double-I inspection signoff was performed and we kept the aircraft; which was a perfectly normal flight. In retrospect there are a few issues I need to point out. First; the QRH procedure seems to assume it's a sensor problem by having Pilots cycle the flaps in flight. In our situation; this action could have resulted in severe aircraft damage. The QRH should reflect the most conservative approach; and cycling an unknown defect with the hopes of resolving a harmless sensor issue is asking for disaster in our situation described here. The second issue is that either the bolt sheared off; or the bolt was improperly installed without using safety wire. Both of these circumstances need to be investigated; and I recommend looking at the last time this bolt was removed and reinstalled. Thirdly; if I had known this was a true flight control surface problem; I would have declared an emergency. Since there were no other symptoms outside the lights; both the Captain and I figured it was a faulty proximity sensor. I'll be more conservative next time; and declare the emergency just to be on the correct side of caution.
The pilot of a B737-700 reported that upon retraction of the flaps; the leading edge (LE) flaps transit light remained illuminated indicating an LE flap was not retracted. After landing; Maintenance found the Number 2 LE flap was missing a bolt on the inboard side of the bullnose.