Date: 201604
Local time of day: 1201-1800
Location: ZZZ.Tower, US
Light: Daylight
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Fuselage
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: Captain; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Ground Strike - Aircraft
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Returned To Departure Airport; Flight Crew Landed As Precaution; General Maintenance Action
Contributing factors: Aircraft; Procedure
Primary problem: Aircraft

Narrative: Captain is Pilot Flying (CA-PF); First Officer is Pilot Monitoring (FO-PM). On take off we received a tail strike annunciation that extinguished after clean up. Although the winds were gusty on takeoff; we did not suspect an actual tail strike. The flight attendants did not hear anything unusual and we did not see or feel anything unusual. In consideration of the Quick Reference Handbook (QRH) guidance to land at the nearest suitable field and out of an abundance of caution; we elected to return to our departure airport for a maintenance inspection which confirmed a tail strike did not occur. During the return; with the flaps up; gear up/handle off; and speed brake deployed; we received unsafe gear indications on all three gear accompanied by the audible gear warning. The hydraulics were all normal and there were no other abnormal indications at that time. The gear warning preceded any gear/flap changes and resolved on its own; possibly in correspondence with retracting the speed brake. We landed uneventfully and maintenance inspected the aircraft. In addition to confirming there was no tail strike event maintenance discovered a significant hydraulic leak of the A system in the left main gear wheel well. Maintenance identified and fixed a loose hydraulic fitting and reviewed the aircraft history of false gear warnings. After several hours of troubleshooting the aircraft was returned to service.During this event; there was not enough information available to us to facilitate decision making. The QRH describes the tail strike annunciation as an indication of a possible tail strike but Vols 1 and 2 describe the tail strike annunciator as a warning for a potential tail strike triggered by specific parameters. Despite a thorough review of the QRH checklist; we could not discern if the tail strike annunciation by itself compelled a return when there was no other evidence or suspicion of a tail strike. In this event; it is possible the tail strike annunciation functioned as a warning and not an actual tail strike; but we have no way to know definitively based on the information in the QRH. It is my strong recommendation that Vol 1; Vol 2 and QRH guidance be expanded to include more information on how the tail strike annunciation operates (i.e. stays illuminated; extinguishes after a time; parameters; warning vs actual; etc.) and whether crews must land at the nearest suitable field for an indication alone. During the return; the audible gear warning was extremely distracting at a very busy time. Had the unsafe gear indication not resolved; we would have needed to run a complicated QRH procedure in a high traffic density area with a loud buzzer that we are unable to silent. This buzzer will move any crew from the yellow to the red or worse simply because it will not silence. This is an unacceptable risk. Many other large aircraft have the ability to silence the audible gear warning horn and clearly safe procedures can and must be developed to add the gear warning silence capability on this aircraft. Finally; there still remains a question of whether the three events; tail strike annunciation; unsafe gear warning; and confirmed hydraulic leak are related in any way. At the first moment of the gear warning; we began to speculate if that could be related to the tail strike annunciation. Had the unsafe gear indication not resolved; the QRH procedure would require the gear handle to be placed in the up position; thereby pressurizing the up line. But; depending on the specific location of the confirmed hydraulic leak; that could have depleted the A system hydraulic fluid. These events could have developed in a number of different ways but we were fortunate to only contemplate those possibilities at ground speed zero.


Second narrative: [Report narrative contained no additional information.]


Synopsis: During takeoff in a B737-800 the Flight Crew received a 'Tail Strike' warning. When returning to the departure airport the Flight Crew received a 'Landing Gear Unsafe' indications on all three gears accompanied by the audible gear warning.