Narrative:

We kept the aircraft for our outbound leg. As we started the before starting engines checklist I noted the weather radar was showing on the nd as operating. I immediately secured it; then called ramp tower to inform them in case of any danger to the ground crew at that gate. I followed that up with a call to the flight office for technical information concerning danger to personnel. I was subsequently told by ramp tower personnel that they were told by maintenance that the radar on our 737's is very low wattage and not a hazard. Information from the flight office and later from the fleet manager gave me the same information. I made sure that the ramp tower; flight office; and fleet manager knew we were uncertain how long it was on at the gate; but worst case was a few minutes short of an hour. We had used the radar 2 or 3 times on the inbound leg. The first officer thought it was off when he checked it after landing. I did not remember specifically turning it off in the terminal area or after landing. It may have been off and the WX button on the glare shield inadvertently depressed while parked; or it may not have been turned off and may have radiated for 50 plus minutes at the gate before we discovered it was on. I do not know which occurred; but treated it as worst case when I reported it. The 737 set up is particularly prone to this problem. In my short time flying it on the line I have found the radar on when arriving at the cockpit twice; both times on my IOE. If one pilot has terr selected and the other has WX selected the only indication visible in the cockpit is the WX printed on one nd; with terr on the other. It is the only WX radar I have ever operated without a clearly marked and unmistakable on switch.

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Original NASA ASRS Text

Title: B737-800 flight crew inadvertently left on their weather radar after landing. The crew surmises the weather radar was left on for just shy of an hour; worst case scenario.

Narrative: We kept the aircraft for our outbound leg. As we started the Before Starting Engines Checklist I noted the weather radar was showing on the ND as operating. I immediately secured it; then called Ramp Tower to inform them in case of any danger to the ground crew at that gate. I followed that up with a call to the Flight Office for technical information concerning danger to personnel. I was subsequently told by Ramp Tower personnel that they were told by maintenance that the radar on our 737's is very low wattage and not a hazard. Information from the Flight Office and later from the Fleet Manager gave me the same information. I made sure that the Ramp Tower; Flight Office; and Fleet Manager knew we were uncertain how long it was on at the gate; but worst case was a few minutes short of an hour. We had used the radar 2 or 3 times on the inbound leg. The First Officer thought it was off when he checked it after landing. I did not remember specifically turning it off in the terminal area or after landing. It may have been off and the WX button on the glare shield inadvertently depressed while parked; or it may not have been turned off and may have radiated for 50 plus minutes at the gate before we discovered it was on. I do not know which occurred; but treated it as worst case when I reported it. The 737 set up is particularly prone to this problem. In my short time flying it on the line I have found the radar on when arriving at the cockpit twice; both times on my IOE. If one pilot has TERR selected and the other has WX selected the only indication visible in the cockpit is the WX printed on one ND; with TERR on the other. It is the only WX radar I have ever operated without a clearly marked and unmistakable ON switch.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.