B737-300 crew had the air ground sensor fail when departing msp.

Attributes
ACN	608505
Time
Date	200402
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : msp.airport
State Reference	MN
Altitude	agl bound lower : 0 agl bound upper : 7000
Environment
Flight Conditions	Marginal
Aircraft 1
Controlling Facilities	tower : msp.tower tower : zzz.tower
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial climbout : intermediate altitude descent : approach landing : roll
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 200 flight time total : 20000 flight time type : 1700
ASRS Report	608505
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 142.5 flight time total : 7000 flight time type : 1750
ASRS Report	608477
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : lndg gears handle would not go past off. other flight crewa other flight crewb
Resolutory Action	controller : provided flight assist controller : issued new clearance flight crew : overrode automation flight crew : diverted to another airport flight crew : landed as precaution other
Consequence	other other
Supplementary
Problem Areas	Company FAA Aircraft
Primary Problem	Aircraft

Narrative:

After takeoff runway 12R at msp, landing gear would not retract, handle would not move past off. After discussion with first officer and based on discussion at the training center during recent proficiency check, decided to use override trigger to raise gear, for second segment climb. Gear retracted normally with override. Leveled off at 7000 ft and 210 KTS. Reviewed landing gear will not retract checklist. After discussion, decided to lower gear and return to takeoff confign. Made PA first and discussed situation with flight attendants. Gear lowered normally. Ran landing gear will not retract irregular. Based on checklist decided to return to msp with gear left down. Did not declare emergency, since saw no need for assistance or equipment. Told flight attendant cabin advisory. When flaps 15 degrees selected got unsilenceable gear warning horn. Resetting air ground sense circuit breaker silenced horn, but was against checklist, so re-pulled circuit breaker and aural warning as well to silence horn. Had 3 green gear lights when circuit breaker was reset. Landed normally. After landing, cabin did not depressurize and both packs overheated and tripped. Yet automatic spdbrakes deployed with reverse thrust actuation, even though they weren't armed. Supplemental information from acn 608477: after takeoff at msp the gear handle would not move past 'off.' after some discussion we decided to raise the gear using the override trigger. When we leveled off at 7000 ft we reconfigured the aircraft and ran the 'landing gear lever will not move up' checklist. We determined the aircraft was still in the ground mode. We completed the checklist and landed uneventfully back at msp. During the entire event we found several things that should have been addressed in the flight manual. The first is when the air/ground circuit breaker is pulled the aircraft is forced into the flight mode. On final when the gear is down and the flaps are moved past 15 degrees the unsafe gear warning horn sounds and is unsilenceable. Then on landing the aircraft did not open the outflow valve when ground was selected.

Original NASA ASRS Text

Title: B737-300 CREW HAD THE AIR GND SENSOR FAIL WHEN DEPARTING MSP.

Narrative: AFTER TKOF RWY 12R AT MSP, LNDG GEAR WOULD NOT RETRACT, HANDLE WOULD NOT MOVE PAST OFF. AFTER DISCUSSION WITH FO AND BASED ON DISCUSSION AT THE TRAINING CTR DURING RECENT PROFICIENCY CHK, DECIDED TO USE OVERRIDE TRIGGER TO RAISE GEAR, FOR SECOND SEGMENT CLB. GEAR RETRACTED NORMALLY WITH OVERRIDE. LEVELED OFF AT 7000 FT AND 210 KTS. REVIEWED LNDG GEAR WILL NOT RETRACT CHKLIST. AFTER DISCUSSION, DECIDED TO LOWER GEAR AND RETURN TO TKOF CONFIGN. MADE PA FIRST AND DISCUSSED SIT WITH FLT ATTENDANTS. GEAR LOWERED NORMALLY. RAN LNDG GEAR WILL NOT RETRACT IRREGULAR. BASED ON CHKLIST DECIDED TO RETURN TO MSP WITH GEAR LEFT DOWN. DID NOT DECLARE EMER, SINCE SAW NO NEED FOR ASSISTANCE OR EQUIP. TOLD FLT ATTENDANT CABIN ADVISORY. WHEN FLAPS 15 DEGS SELECTED GOT UNSILENCEABLE GEAR WARNING HORN. RESETTING AIR GND SENSE CIRCUIT BREAKER SILENCED HORN, BUT WAS AGAINST CHKLIST, SO RE-PULLED CIRCUIT BREAKER AND AURAL WARNING AS WELL TO SILENCE HORN. HAD 3 GREEN GEAR LIGHTS WHEN CIRCUIT BREAKER WAS RESET. LANDED NORMALLY. AFTER LNDG, CABIN DID NOT DEPRESSURIZE AND BOTH PACKS OVERHEATED AND TRIPPED. YET AUTO SPDBRAKES DEPLOYED WITH REVERSE THRUST ACTUATION, EVEN THOUGH THEY WEREN'T ARMED. SUPPLEMENTAL INFO FROM ACN 608477: AFTER TKOF AT MSP THE GEAR HANDLE WOULD NOT MOVE PAST 'OFF.' AFTER SOME DISCUSSION WE DECIDED TO RAISE THE GEAR USING THE OVERRIDE TRIGGER. WHEN WE LEVELED OFF AT 7000 FT WE RECONFIGURED THE ACFT AND RAN THE 'LNDG GEAR LEVER WILL NOT MOVE UP' CHKLIST. WE DETERMINED THE ACFT WAS STILL IN THE GND MODE. WE COMPLETED THE CHKLIST AND LANDED UNEVENTFULLY BACK AT MSP. DURING THE ENTIRE EVENT WE FOUND SEVERAL THINGS THAT SHOULD HAVE BEEN ADDRESSED IN THE FLT MANUAL. THE FIRST IS WHEN THE AIR/GND CIRCUIT BREAKER IS PULLED THE ACFT IS FORCED INTO THE FLT MODE. ON FINAL WHEN THE GEAR IS DOWN AND THE FLAPS ARE MOVED PAST 15 DEGS THE UNSAFE GEAR WARNING HORN SOUNDS AND IS UNSILENCEABLE. THEN ON LNDG THE ACFT DID NOT OPEN THE OUTFLOW VALVE WHEN GND WAS SELECTED.

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.