An LC320 declared an emergency due to nose landing gear failed to extend. Caused by a failed hydraul...

Attributes
ACN	683315
Time
Date	200601
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft Low Wing 1 Eng Retractable Gear
Operating Under FAR Part	Part 91
Flight Phase	landing : roll
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 1 flight time total : 7500 flight time type : 64
ASRS Report	683315
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : nose gear position indication other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : landed in emergency condition
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

While landing from a local proficiency flight; was unable to get the nosewheel locked down. Mains both locked ok; but no indication of the nose down and locked. A number of attempts to extend with alternate extension; porpoising the aircraft; yawing the aircraft; and pulling some G's were ineffective. Announced situation on ZZZ unicom (unmonitored and no traffic was in the local area). Made a normal approach. Shut off the mixture control on short final and held the nose off as long as possible. Nose gear folded (if indeed it was ever extended). The propeller tips bent as the engine was still windmilling; but not under power. Engine did not stop suddenly. Only damage to airplane was to the propeller and the lower fiberglas engine cowling. Cause unknown. Callback conversation with reporter revealed the following information: the reporter stated the landing gear is controled and operated hydraulically and the failure of the nose gear to extend was a hydraulic switch which failed; allowing hydraulic fluid to bypass the extend cylinder. The propeller tips were bent and the lower engine cowling sustained scratches. The engine was sent off to the manufacturer and found ok with no damage but did find corrosion on the crankshaft.

Original NASA ASRS Text

Title: AN LC320 DECLARED AN EMER DUE TO NOSE LNDG GEAR FAILED TO EXTEND. CAUSED BY A FAILED HYD SWITCH BYPASSING THE EXTEND CYLINDER.

Narrative: WHILE LNDG FROM A LCL PROFICIENCY FLT; WAS UNABLE TO GET THE NOSEWHEEL LOCKED DOWN. MAINS BOTH LOCKED OK; BUT NO INDICATION OF THE NOSE DOWN AND LOCKED. A NUMBER OF ATTEMPTS TO EXTEND WITH ALTERNATE EXTENSION; PORPOISING THE ACFT; YAWING THE ACFT; AND PULLING SOME G'S WERE INEFFECTIVE. ANNOUNCED SITUATION ON ZZZ UNICOM (UNMONITORED AND NO TFC WAS IN THE LCL AREA). MADE A NORMAL APCH. SHUT OFF THE MIXTURE CTL ON SHORT FINAL AND HELD THE NOSE OFF AS LONG AS POSSIBLE. NOSE GEAR FOLDED (IF INDEED IT WAS EVER EXTENDED). THE PROP TIPS BENT AS THE ENG WAS STILL WINDMILLING; BUT NOT UNDER PWR. ENG DID NOT STOP SUDDENLY. ONLY DAMAGE TO AIRPLANE WAS TO THE PROP AND THE LOWER FIBERGLAS ENG COWLING. CAUSE UNKNOWN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE LNDG GEAR IS CTLED AND OPERATED HYDRAULICALLY AND THE FAILURE OF THE NOSE GEAR TO EXTEND WAS A HYD SWITCH WHICH FAILED; ALLOWING HYD FLUID TO BYPASS THE EXTEND CYLINDER. THE PROP TIPS WERE BENT AND THE LOWER ENG COWLING SUSTAINED SCRATCHES. THE ENG WAS SENT OFF TO THE MANUFACTURER AND FOUND OK WITH NO DAMAGE BUT DID FIND CORROSION ON THE CRANKSHAFT.

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.

An LC320 declared an emergency due to nose landing gear failed to extend. Caused by a failed hydraulic switch bypassing the extend cylinder.