Small transport aircraft has nose gear retract as engine started. Propeller strikes ground.

Attributes
ACN	224494
Time
Date	199210
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : 76s
State Reference	WA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air taxi
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 222 flight time total : 7571 flight time type : 287
ASRS Report	224494
Person 2
Affiliation	Other
Function	other personnel other
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

During start of the right engine (the first to be started) the nose gear retracted causing the right propeller to strike the ground and stop. During the preflight I observed the main gear doors open. Maintenance had inspected and washed the aircraft during the night shift. I knew that the doors would close when the gear handle was placed down with the engines running. After the preflight and engine runup, I loaded the baggage, completed the manifest and loaded the 3 passenger. Using the starting engines checklist, I noted the 3 green gear lights. As the right engine started the nose gear retracted. Several possibilities exist for why the gear retracted. A possible corrective action would be to place the gear handle down prior to engine starts. This would ensure the handle position, ensure the gear system is pressurized and check the first hydraulic pump. Manufacturer calls for the handle to be placed down after the first engine is started. This is the first time the gear handle position is checked. Callback conversation with reporter revealed the following information: reporter states that gear doors can and were opened manually when aircraft washed and some maintenance done. Consensus is that water got on or into the switch that energized the gear horn and activates the solenoid to landing gear. The water apparently caused switch to fail. He does not know of any other instance, believes it to be an isolated instance. Propeller damage created need to tear down the engine, plus some damage to pitot tube.

Original NASA ASRS Text

Title: SMT ACFT HAS NOSE GEAR RETRACT AS ENG STARTED. PROP STRIKES GND.

Narrative: DURING START OF THE R ENG (THE FIRST TO BE STARTED) THE NOSE GEAR RETRACTED CAUSING THE R PROP TO STRIKE THE GND AND STOP. DURING THE PREFLT I OBSERVED THE MAIN GEAR DOORS OPEN. MAINT HAD INSPECTED AND WASHED THE ACFT DURING THE NIGHT SHIFT. I KNEW THAT THE DOORS WOULD CLOSE WHEN THE GEAR HANDLE WAS PLACED DOWN WITH THE ENGS RUNNING. AFTER THE PREFLT AND ENG RUNUP, I LOADED THE BAGGAGE, COMPLETED THE MANIFEST AND LOADED THE 3 PAX. USING THE STARTING ENGS CHKLIST, I NOTED THE 3 GREEN GEAR LIGHTS. AS THE R ENG STARTED THE NOSE GEAR RETRACTED. SEVERAL POSSIBILITIES EXIST FOR WHY THE GEAR RETRACTED. A POSSIBLE CORRECTIVE ACTION WOULD BE TO PLACE THE GEAR HANDLE DOWN PRIOR TO ENG STARTS. THIS WOULD ENSURE THE HANDLE POS, ENSURE THE GEAR SYS IS PRESSURIZED AND CHK THE FIRST HYD PUMP. MANUFACTURER CALLS FOR THE HANDLE TO BE PLACED DOWN AFTER THE FIRST ENG IS STARTED. THIS IS THE FIRST TIME THE GEAR HANDLE POS IS CHKED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT GEAR DOORS CAN AND WERE OPENED MANUALLY WHEN ACFT WASHED AND SOME MAINT DONE. CONSENSUS IS THAT WATER GOT ON OR INTO THE SWITCH THAT ENERGIZED THE GEAR HORN AND ACTIVATES THE SOLENOID TO LNDG GEAR. THE WATER APPARENTLY CAUSED SWITCH TO FAIL. HE DOES NOT KNOW OF ANY OTHER INSTANCE, BELIEVES IT TO BE AN ISOLATED INSTANCE. PROP DAMAGE CREATED NEED TO TEAR DOWN THE ENG, PLUS SOME DAMAGE TO PITOT TUBE.

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.