Date: 201911
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Flap/Slat Indication
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Confusion
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Manuals; Aircraft
Primary problem: Aircraft

Narrative: This [report] is submitted in recognition of a scenario which is not addressed in the QRH - No LE device indicating lights upon landing configuration. This is not a one-off event since it occurred to another crew and aircraft last week. Situations were identical but crew analysis and actions were very different. No-flap landing for one and normal flap 30 landing for the other. Both flights landed uneventfully. Seems some QRH guidance here would be useful in future occurrences. An [incident report] also submitted to Company Flight Operations.On [flight]; an instance of no LE device indication on approach caused Crew confusion because it's not addressed in the QRH. On initial approach into ZZZ; aircraft was configured for landing (gear down; flaps 30). All things appeared normal mechanically; however; we noticed no green LE FLAPS EXT light. Also no LE device annunciation panel lights. They were blank. No roll tendency was evident; press to test indicated operable LE device lights; circuit breakers in; and TE flap gauge indicated normally. Upon configuring everything appeared and felt normal. The only thing not normal was the absence of LE device lights.Conducted normal go-around to investigate and realized that this situation is not addressed in QRH. There is no discussion or guidance. Conducted a phone patch to Maintenance for enlightenment and Technician indicated that it was more than likely due to a PSEU/ FSEU fault which cannot be resolved during flight. Since this scenario is not addressed in the QRH; we had some discussion of no-flap or flap 15 landing but only because we were trying to make our situation 'fit' one of the QRH scenarios. Fortunately we had a jumpseat pilot in the cabin who could verify LE device and flap position for us. So those non-normal landing configurations were eventually ruled out because our situation did not warrant the increased risk. Using [resource management] by taking into account what we could feel and see; verification of LE and flap position with jumpseat pilot; and discussion with Maintenance; our issue appeared to be an indication problem; not an actual flight control problem. A normal configuration and landing into ZZZ ensued. PSEU light illuminated on landing. (This was due to the lack of info from the FSEU). ZZZ Contract Maintenance investigated and found the FSEU was at fault.




Synopsis: B737-700 Captain reported that a slat malfunction occurred for which there was no QRH procedure that resulted in a precautionary landing.