The landing gear would not retract when the gear handle was moved to the up position after takeoff.

Attributes
ACN	318866
Time
Date	199510
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : phl
State Reference	PA
Altitude	agl bound lower : 50 agl bound upper : 50
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : phl
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	climbout : takeoff landing other other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 300 flight time total : 14000 flight time type : 11500
ASRS Report	318866
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical non adherence other other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

After takeoff, unable to raise gear. Returned to land at phl. Landed with gear doors open. Later (postflt) found maintenance bypass handle extended. During preflight, found no indication that gear system hydraulics were abnormal. Cycled maintenance bypass valve several times to check door operations. Suspect that handle is of a faulty design. Snap closure can be snapped shut and handle can then be pushed up flush with belly of aircraft. This allows the indications in the gear system to appear normal, but the maintenance bypass lever is just pushed up flush.

Original NASA ASRS Text

Title: THE LNDG GEAR WOULD NOT RETRACT WHEN THE GEAR HANDLE WAS MOVED TO THE UP POS AFTER TKOF.

Narrative: AFTER TKOF, UNABLE TO RAISE GEAR. RETURNED TO LAND AT PHL. LANDED WITH GEAR DOORS OPEN. LATER (POSTFLT) FOUND MAINT BYPASS HANDLE EXTENDED. DURING PREFLT, FOUND NO INDICATION THAT GEAR SYS HYDS WERE ABNORMAL. CYCLED MAINT BYPASS VALVE SEVERAL TIMES TO CHK DOOR OPS. SUSPECT THAT HANDLE IS OF A FAULTY DESIGN. SNAP CLOSURE CAN BE SNAPPED SHUT AND HANDLE CAN THEN BE PUSHED UP FLUSH WITH BELLY OF ACFT. THIS ALLOWS THE INDICATIONS IN THE GEAR SYS TO APPEAR NORMAL, BUT THE MAINT BYPASS LEVER IS JUST PUSHED UP FLUSH.

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.