A PA30 on a post maintenance test flight developed a streaming fuel cap leak requiring an engine shu...

Attributes
ACN	719635
Time
Date	200612
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cak.airport
State Reference	OH
Altitude	msl single value : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cak.tracon
Operator	general aviation : personal
Make Model Name	PA-30 Twin Comanche
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	VFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : atp pilot : cfi
Experience	flight time total : 19500
ASRS Report	719635
Person 2
Affiliation	other
Function	observation : observer
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : landed in emergency condition flight crew : declared emergency
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

During a maintenance return to service flight; when approximately 15 NM southeast of airport; while cruising at 4000 ft; I noticed a stream of fuel leaving the left wing. Not knowing exactly where it was coming from; I shut down and feathered the left engine. We turned back towards the airport. While lining up for final approach on runway 23; the landing gear would not extend. We leveled off and proceeded to circle to the northeast at 1 mi of the landing runway threshold. We proceeded to run the manual extension procedure. As I flew the aircraft; the second pilot/observer was able to carry out the procedure/checklist. After we verified the gear down; we proceeded to land without incident. We found a faulty main gas tank cap seal caused siphoning of the fuel. Callback conversation with reporter revealed the following information: the reporter stated the aircraft type was a PA30. He said that until after landing they did not know that the fuel was streaming from the fuel cap because they could not clearly see where it was streaming from. He was very concerned about the fuel especially if the gear could not be extended. The pilot in the right seat was a volunteer who did not fully comprehend the potential danger the aircraft was experiencing.

Original NASA ASRS Text

Title: A PA30 ON A POST MAINT TEST FLT DEVELOPED A STREAMING FUEL CAP LEAK REQUIRING AN ENG SHUTDOWN FOLLOWED BY A NORMAL GEAR EXTENSION FAILURE.

Narrative: DURING A MAINT RETURN TO SVC FLT; WHEN APPROX 15 NM SE OF ARPT; WHILE CRUISING AT 4000 FT; I NOTICED A STREAM OF FUEL LEAVING THE L WING. NOT KNOWING EXACTLY WHERE IT WAS COMING FROM; I SHUT DOWN AND FEATHERED THE L ENG. WE TURNED BACK TOWARDS THE ARPT. WHILE LINING UP FOR FINAL APCH ON RWY 23; THE LNDG GEAR WOULD NOT EXTEND. WE LEVELED OFF AND PROCEEDED TO CIRCLE TO THE NE AT 1 MI OF THE LNDG RWY THRESHOLD. WE PROCEEDED TO RUN THE MANUAL EXTENSION PROC. AS I FLEW THE ACFT; THE SECOND PLT/OBSERVER WAS ABLE TO CARRY OUT THE PROC/CHKLIST. AFTER WE VERIFIED THE GEAR DOWN; WE PROCEEDED TO LAND WITHOUT INCIDENT. WE FOUND A FAULTY MAIN GAS TANK CAP SEAL CAUSED SIPHONING OF THE FUEL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT TYPE WAS A PA30. HE SAID THAT UNTIL AFTER LNDG THEY DID NOT KNOW THAT THE FUEL WAS STREAMING FROM THE FUEL CAP BECAUSE THEY COULD NOT CLEARLY SEE WHERE IT WAS STREAMING FROM. HE WAS VERY CONCERNED ABOUT THE FUEL ESPECIALLY IF THE GEAR COULD NOT BE EXTENDED. THE PLT IN THE R SEAT WAS A VOLUNTEER WHO DID NOT FULLY COMPREHEND THE POTENTIAL DANGER THE ACFT WAS EXPERIENCING.

Data retrieved from NASA's ASRS site as of January 2009 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.

A PA30 on a post maintenance test flight developed a streaming fuel cap leak requiring an engine shutdown followed by a normal gear extension failure.