20110904020339I

Incident · Minor damage

FAA incident report · Siai-Marchetti SF.260TP · Santa Monica, CA · September 4, 2011

Date
September 4, 2011 · 11:34 local
Place
Santa Monica, CA
Airport
Santa Monica Municipal
Phase of flight
Takeoff: Departure Roll
Operating rules
General operating rules (Part 91)
Damage
Minor damage
Aircraft
N260DP
Reported as
Siai-Marchetti SF.260TP
Reported engine
Allison 250-B17 series
People aboard
1
Fatal injuries
0
Other injuries
0
Pilot’s certificates
Airline transport, flight instructor
Pilot’s flight hours
4,000 total500 in this make and model15 in the last 90 days

From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry by N-number and event date, checked against the reported make and model; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

What happened

The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.

On Sunday, September 4, 2011, at 11:34 pacific standard time, a dark green 1983 Siai-Marchetti, N260DP taxied onto runway 21 for a visual departure southwest bound. During the take-off roll at approximately 45 knots the nose gear of the aircraft retracted while the aircraft's main wheels were still on the runway. The aircraft's three bladed hartzel propeller struck the runway surface and the aircraft veered to the right side of the runway coming to rest on the infield approximately 400 feet from the beginning of the take-off roll adjacent to the wind sock. The pilot was unaware that the landing gear lever had been accidentally placed in the up position at the time the aircraft was serviced on September 1, 2011. The mechanic who is employed by the owner of the aircraft was asked to inspect and service one of the landing gear indicator light bulbs. The mechanic had placed the landing gear lever in the up position to better access the indicator rheostat and bulb. The mechanic failed to assure the landing gear lever was in the down position at the completion of work. On the day of the flight, the pilot failed to positively check the landing gear control lever during the pre-flight of the aircraft. The landing gear is a retractable tricycle landing gear which consists of a main landing gear, and nose landing gear. The nose landing gear consists of a single wheel mounted on a shock strut and retracting rearward into the fuselage nose section. The landing gear system is provided with a safety system (squat switch) to prevent the inadvertent retraction when on the ground. However, the aircraft pilot operating handbook (POH) notes: "movement of the aircraft during ground runs can disactivate the safety switch." The squat switch is located on the left main landing gear strut. When the main landing gear strut extends the switch is depressed, thus closing the electrical circuit and energizing the system. When the landing gear lever is in the "up" position with the switch depressed the electromechanical actuator will begin the retraction cycle of the landing gear. During the take-off roll as the aircraft began to enter ground effect the aircraft's main wheels began to lift from the runway while the nose wheel was still on the runway. This "wheelbarrow" effect caused the safety squat switch to become depressed deactivating the safety system and beginning the retraction cycle of the landing gear. The combined weight on the nose of the aircraft and the forward thrust being produced by the propeller created a pitch down moment. As the nose began to retract in the wheel well the propeller struck the runway. The pilot aborted the takeoff and the aircraft veered to the right of the runway with the nose retracted and the two main landing gear struts extended.

As the FAA filed it

ON SUNDAY, SEPTEMBER 4, 2011, AT 11:34 PACIFIC STANDARD TIME, A DARK GREEN 1983 SIAI-MARCHETTI, N260DP TAXIED ONTO RUNWAY 21 FOR A VISUAL DEPARTURE SOUTHWEST BOUND. DURING THE TAKE-OFF ROLL AT APPROXIMATELY 45 KNOTS THE NOSE GEAR OF THE AIRCRAFT RETRACTED WHILE THE AIRCRAFT'S MAIN WHEELS WERE STILL ON THE RUNWAY. THE AIRCRAFT'S THREE BLADED HARTZEL PROPELLER STRUCK THE RUNWAY SURFACE AND THE AIRCRAFT VEERED TO THE RIGHT SIDE OF THE RUNWAY COMING TO REST ON THE INFIELD APPROXIMATELY 400 FEET FROM THE BEGINNING OF THE TAKE-OFF ROLL ADJACENT TO THE WIND SOCK.THE PILOT WAS UNAWARE THAT THE LANDING GEAR LEVER HAD BEEN ACCIDENTALLY PLACED IN THE UP POSITION AT THE TIME THE AIRCRAFT WAS SERVICED ON SEPTEMBER 1, 2011. THE MECHANIC WHO IS EMPLOYED BY THE OWNER OF THE AIRCRAFT WAS ASKED TO INSPECT AND SERVICE ONE OF THE LANDING GEAR INDICATOR LIGHT BULBS. THE MECHANIC HAD PLACED THE LANDING GEAR LEVER IN THE UP POSITION TO BETTER ACCESS THE INDICATOR RHEOSTAT AND BULB. THE MECHANIC FAILED TO ASSURE THE LANDING GEAR LEVER WAS IN THE DOWN POSITION AT THE COMPLETION OF WORK.ON THE DAY OF THE FLIGHT, THE PILOT FAILED TO POSITIVELY CHECK THE LANDING GEAR CONTROL LEVER DURING THE PRE-FLIGHT OF THE AIRCRAFT.THE LANDING GEAR IS A RETRACTABLE TRICYCLE LANDING GEAR WHICH CONSISTS OF A MAIN LANDING GEAR, AND NOSE LANDING GEAR. THE NOSE LANDING GEAR CONSISTS OF A SINGLE WHEEL MOUNTED ON A SHOCK STRUT AND RETRACTING REARWARD INTO THE FUSELAGE NOSE SECTION. THE LANDING GEAR SYSTEM IS PROVIDED WITH A SAFETY SYSTEM (SQUAT SWITCH) TO PREVENT THE INADVERTENT RETRACTION WHEN ON THE GROUND. HOWEVER, THE AIRCRAFT PILOT OPERATING HANDBOOK (POH) NOTES: "MOVEMENT OF THE AIRCRAFT DURING GROUND RUNS CAN DISACTIVATE THE SAFETY SWITCH." THE SQUAT SWITCH IS LOCATED ON THE LEFT MAIN LANDING GEAR STRUT. WHEN THE MAIN LANDING GEAR STRUT EXTENDS THE SWITCH IS DEPRESSED, THUS CLOSING THE ELECTRICAL CIRCUIT AND ENERGIZING THE SYSTEM. WHEN THE LANDING GEAR LEVER IS IN THE "UP" POSITION WITH THE SWITCH DEPRESSED THE ELECTROMECHANICAL ACTUATOR WILL BEGIN THE RETRACTION CYCLE OF THE LANDING GEAR.DURING THE TAKE-OFF ROLL AS THE AIRCRAFT BEGAN TO ENTER GROUND EFFECT THE AIRCRAFT'S MAIN WHEELS BEGAN TO LIFT FROM THE RUNWAY WHILE THE NOSE WHEEL WAS STILL ON THE RUNWAY. THIS "WHEELBARROW" EFFECT CAUSED THE SAFETY SQUAT SWITCH TO BECOME DEPRESSED DEACTIVATING THE SAFETY SYSTEM AND BEGINNING THE RETRACTION CYCLE OF THE LANDING GEAR. THE COMBINED WEIGHT ON THE NOSE OF THE AIRCRAFT AND THE FORWARD THRUST BEING PRODUCED BY THE PROPELLER CREATED A PITCH DOWN MOMENT. AS THE NOSE BEGAN TO RETRACT IN THE WHEEL WELL THE PROPELLER STRUCK THE RUNWAY. THE PILOT ABORTED THE TAKEOFF AND THE AIRCRAFT VEERED TO THE RIGHT OF THE RUNWAY WITH THE NOSE RETRACTED AND THE TWO MAIN LANDING GEAR STRUTS EXTENDED.