Narrative:

Our flight departed runway 36 at clt normal takeoff. Captain called for 'gear up.' gear handle would not move from down position. Captain flew and operated radio while I referred to aircraft pilot's handbook. Captain coordinated lower airspeed with maintenance control to stay below 200 KT gear speed limit. During climb out, a lift dumper fault message appeared on MFDU. The working in the abnormal procedure was ambiguous in this case -- we weren't sure if the lift dumper fault message qualified as a 'grd/flight control' fault message or not. I called clt operations on the #2 radio to get a clarification from maintenance control -- the maintenance supervisor did not know the answer. We asked him to call pit and get a clarification for us. By the time he called back, we were about halfway to cae. The WX was considerably better in cae than clt. The 'relayed' information that we had from maintenance left some doubt as to possible air/ground logic problems that might arise if we overrode the gear to bring it up, so we elected to just leave the gear down for the few remaining mi to cae, where we could land with good WX and then talk directly to pit maintenance on the phone. Recommendation -- change the abnormal procedure in the pilot's handbook to eliminate the ambiguous working, and provide more specific guidance. Callback conversation with reporter revealed the following information. The source of the problem was a failed air/ground sensor switch, this leading to the lift dumper fault message. The wording the abnormal procedures checklist may have been ambiguous; the abnormal procedures notes that 'a' air/ground fault message is the result of... Rather that 'the' air/ground fault message is a result of... The flight crew was confused that there may be a family of such error causes and was unsure if procedures allowed gear retraction override (which in fact was permissible). The reporter has filed a report with his company noting the alleged misleading wording of the abnormal procedures checklist. The company noted that there have been a number of like failures with the air/ground sensor, and has instituted a change-out of sensors rather than any wording change in the checklist.

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Original NASA ASRS Text

Title: FLC OF ACR MLG EXPERIENCES DIFFICULTY IN INTERPRETING THE ABNORMAL PROCS CHKLIST UPON FAILURE OF AN AIR/GND SENSOR SWITCH ON DEP FROM CLT.

Narrative: OUR FLT DEPARTED RWY 36 AT CLT NORMAL TKOF. CAPT CALLED FOR 'GEAR UP.' GEAR HANDLE WOULD NOT MOVE FROM DOWN POS. CAPT FLEW AND OPERATED RADIO WHILE I REFERRED TO ACFT PLT'S HANDBOOK. CAPT COORDINATED LOWER AIRSPD WITH MAINT CTL TO STAY BELOW 200 KT GEAR SPD LIMIT. DURING CLBOUT, A LIFT DUMPER FAULT MESSAGE APPEARED ON MFDU. THE WORKING IN THE ABNORMAL PROC WAS AMBIGUOUS IN THIS CASE -- WE WEREN'T SURE IF THE LIFT DUMPER FAULT MESSAGE QUALIFIED AS A 'GRD/FLT CTL' FAULT MESSAGE OR NOT. I CALLED CLT OPS ON THE #2 RADIO TO GET A CLARIFICATION FROM MAINT CTL -- THE MAINT SUPVR DID NOT KNOW THE ANSWER. WE ASKED HIM TO CALL PIT AND GET A CLARIFICATION FOR US. BY THE TIME HE CALLED BACK, WE WERE ABOUT HALFWAY TO CAE. THE WX WAS CONSIDERABLY BETTER IN CAE THAN CLT. THE 'RELAYED' INFO THAT WE HAD FROM MAINT LEFT SOME DOUBT AS TO POSSIBLE AIR/GND LOGIC PROBLEMS THAT MIGHT ARISE IF WE OVERRODE THE GEAR TO BRING IT UP, SO WE ELECTED TO JUST LEAVE THE GEAR DOWN FOR THE FEW REMAINING MI TO CAE, WHERE WE COULD LAND WITH GOOD WX AND THEN TALK DIRECTLY TO PIT MAINT ON THE PHONE. RECOMMENDATION -- CHANGE THE ABNORMAL PROC IN THE PLT'S HANDBOOK TO ELIMINATE THE AMBIGUOUS WORKING, AND PROVIDE MORE SPECIFIC GUIDANCE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. THE SOURCE OF THE PROBLEM WAS A FAILED AIR/GND SENSOR SWITCH, THIS LEADING TO THE LIFT DUMPER FAULT MESSAGE. THE WORDING THE ABNORMAL PROCS CHKLIST MAY HAVE BEEN AMBIGUOUS; THE ABNORMAL PROCS NOTES THAT 'A' AIR/GND FAULT MESSAGE IS THE RESULT OF... RATHER THAT 'THE' AIR/GND FAULT MESSAGE IS A RESULT OF... THE FLC WAS CONFUSED THAT THERE MAY BE A FAMILY OF SUCH ERROR CAUSES AND WAS UNSURE IF PROCS ALLOWED GEAR RETRACTION OVERRIDE (WHICH IN FACT WAS PERMISSIBLE). THE RPTR HAS FILED A RPT WITH HIS COMPANY NOTING THE ALLEGED MISLEADING WORDING OF THE ABNORMAL PROCS CHKLIST. THE COMPANY NOTED THAT THERE HAVE BEEN A NUMBER OF LIKE FAILURES WITH THE AIR/GND SENSOR, AND HAS INSTITUTED A CHANGE-OUT OF SENSORS RATHER THAN ANY WORDING CHANGE IN THE CHKLIST.

Data retrieved from NASA's ASRS site as of July 2007 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.