Narrative:

During climb; flight crew contacted me (dispatcher) on the radio about a landing gear aural warning going off in the cockpit. I got the MD11 maintenance representative on the line with us. It was mentioned that associated maintenance had just been completed on this item and was the possible reason for the malfunction and aural warning. Maintenance suggested that in order to clear the warning that a recycle of the gear system would need to be completed. The crew told maintenance that at the current altitude; speed; and airspace that the procedure could not be performed. The crew and maintenance agreed that although the aural warning was very distracting; it was strictly an indication issue. The crew then asked maintenance if they would be able to pull the associated circuit breaker to silence the noise and if doing so; what system(s) would be affected. Maintenance said that he had no procedure for doing so and it would be at captain's discretion if he decided to do this. The crew again asked for affected system(s) with the circuit breaker and then requested to discuss further with an md-11 sme (subject matter expert on the md-11). Maintenance relayed that he thought the breaker affected the takeoff warning; landing gear horn and cabin altitude warning; but would continue to research and have the dispatcher forward any further information. The sme was patched into the discussion on the radio; and after being briefed by the crew on the matter; he contributed his concerns regarding the cabin altitude warning during the cruise phase of flight. It was further discussed that the cabin altitude could be visually checked and periodically monitored by the crew by pushing the breaker back in. The sme felt if the crew was diligent in monitoring the system; that it was safe to continue. The crew reported that upon initial descent they would reset the circuit breaker in order to have the landing gear horn for the approach segment of the flight. Everyone involved; based on the information that was given and available; felt it was safe to continue at that time. I assured the crew that maintenance control and I would continue to research the circuit breaker and let him know what and if any new information was available. I contacted maintenance control by phone for further clarification on the circuit breaker and sent the following messages via ACARS to the crew: per maintenance circuit breaker cntls tkoff warning landing gear horn and cabin altitude maintenance suggests that at your discretion to push the breaker in about once an hour to see if aural warning still exists. The aircraft continued without incidence and diverted for maintenance. It was brought to my attention by the maintenance personnel that handled this flight; that this circuit breaker also controlled the warning for the cargo fire detection system. This was not discussed nor revealed to any of the involved parties at the time of the flight. Since this new information was brought forth; I feel that this flight would have returned to the departure airport rather than continuing on with the circuit breaker pulled.

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Original NASA ASRS Text

Title: An MD11's landing gear warning was sounding after takeoff. Following much discussion; the warning system's circuit breaker was pulled; but the crew did not know the cargo fire detection system was also disabled.

Narrative: During climb; flight crew contacted me (Dispatcher) on the radio about a landing gear aural warning going off in the cockpit. I got the MD11 Maintenance Representative on the line with us. It was mentioned that associated maintenance had just been completed on this item and was the possible reason for the malfunction and aural warning. Maintenance suggested that in order to clear the warning that a recycle of the gear system would need to be completed. The crew told Maintenance that at the current altitude; speed; and airspace that the procedure could not be performed. The crew and Maintenance agreed that although the aural warning was very distracting; it was strictly an indication issue. The crew then asked Maintenance if they would be able to pull the associated circuit breaker to silence the noise and if doing so; what system(s) would be affected. Maintenance said that he had no procedure for doing so and it would be at Captain's discretion if he decided to do this. The crew again asked for affected system(s) with the circuit breaker and then requested to discuss further with an MD-11 SME (Subject Matter Expert on the MD-11). Maintenance relayed that he thought the breaker affected the takeoff warning; landing gear horn and cabin altitude warning; but would continue to research and have the Dispatcher forward any further information. The SME was patched into the discussion on the radio; and after being briefed by the crew on the matter; he contributed his concerns regarding the cabin altitude warning during the cruise phase of flight. It was further discussed that the cabin altitude could be visually checked and periodically monitored by the crew by pushing the breaker back in. The SME felt if the crew was diligent in monitoring the system; that it was safe to continue. The crew reported that upon initial descent they would reset the circuit breaker in order to have the landing gear horn for the approach segment of the flight. Everyone involved; based on the information that was given and available; felt it was safe to continue at that time. I assured the crew that Maintenance Control and I would continue to research the circuit breaker and let him know what and if any new information was available. I contacted Maintenance Control by phone for further clarification on the circuit breaker and sent the following messages via ACARS to the crew: PER MAINTENANCE CIRCUIT BREAKER CNTLS TKOFF WARNING LANDING GEAR HORN AND CABIN ALT MAINTENANCE SUGGESTS THAT AT YOUR DISCRETION TO PUSH THE BREAKER IN ABOUT ONCE AN HOUR TO SEE IF AURAL WARNING STILL EXISTS. The aircraft continued without incidence and diverted for maintenance. It was brought to my attention by the Maintenance personnel that handled this flight; that this circuit breaker also controlled the warning for the cargo fire detection system. This was not discussed nor revealed to any of the involved parties at the time of the flight. Since this new information was brought forth; I feel that this flight would have returned to the departure airport rather than continuing on with the circuit breaker pulled.

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.