B737 Undifferentiated or Other Model
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 89; Flight Crew Total 8249; Flight Crew Type 2699
Troubleshooting; Communication Breakdown; Confusion
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Flight Crew Overcame Equipment Problem
Human Factors; Company Policy; Manuals; Procedure
The BWI 10-7 page shows that ACARS reception is a known problem at certain gates. GPS is not mentioned. We brought the aircraft into BWI gate and were getting it ready to quick-turn. After turning the IRS switches to NAV; the First Officer and I noted that there was no GPS reception. The amber GPS light illuminated on the overhead panel. We referenced the QRH; and I called Maintenance Control. I didn't write it up since I suspected that this was a reception problem due to the gate and not an aircraft problem. Maintenance Control said that GPS signal reception was a known issue at BWI and suggested cycling the MMR circuit breakers which we did just to see if that would help. I made a log entry on cycling the breakers but it didn't resolve the issue. We followed the Flight Manual guidance on initializing the FMC using airport reference data and agreed with Maintenance Control that this was an airport gate anomaly and not an aircraft malfunction. The First Officer and I programmed the FMC and conferred on a plan to taxi to the deice pad to acquire GPS signal and regain our capabilities. If we were unable to get GPS signal; we would taxi back to the gate. We had high confidence this plan was safe without compromising safety. We taxied to the deice pad off the end of RWY 15R; and it took about 5 minutes to get both GPS's back online. Once they were operational; we accomplished all pre-departure checklists and took off uneventfully. I'm uneasy because there is nothing solid in the FM or FOM that deals with 'known ground anomalies' (even if a station advertised them) and repositioning the aircraft to resolve it. In hindsight I should have called dispatch and the maintenance supervisor for clarification on accomplishing this 'fix'.
B737 Captain reported during preflight at the gate; they experienced a lack of GPS signal reception in an area of known radio signal reception degradation.