DEADHORSE, AK, USA
N4059H
HELIO H700
THE PILOT, WITH THREE PASSENGERS, WAS DEPARTING A REMOTE AIRSTRIP ON THE RETURN PORTION OF AN ON-DEMAND CHARTER FLIGHT. THE AIRPLANE, EQUIPPED WITH WHEEL/SKIS, WAS BEING OPERATED WITH THE SKIS RETRACTED FROM A SNOW COVERED STRIP THAT WAS ABOUT 850 FEET LONG. DURING THE TAKEOFF ROLL, THE RIGHT MAIN LANDING GEAR SKI CONTACTED THE SNOW, SLOWING THE AIRPLANE'S ACCELERATION AND PRODUCING A PULL TO THE RIGHT. THE PILOT APPLIED LEFT RUDDER CONTROL AND LEFT BRAKE PRESSURE TO MAINTAIN DIRECTIONAL CONTROL. NEAR THE END OF THE TAKEOFF AREA, THE PILOT ROTATED THE AIRPLANE, HOWEVER, IT SETTLED SLIGHTLY AND THE RIGHT GEAR SKI TIP CONTACTED THE SNOW. THE RIGHT SKI MECHANISM WAS TORN FROM THE AIRPLANE. THE AIRPLANE BECAME AIRBORNE AND THE PILOT DECIDED TO PROCEED TO AN AIRPORT WHERE EMERGENCY RESCUE EQUIPMENT WAS AVAILABLE. DURING TOUCH DOWN AT THE DESTINATION RUNWAY, THE RIGHT MAIN GEAR COLLAPSED. THE FORWARD SKI LIMIT-CABLE BRACKET BOLTS WERE FOUND SHEARED. THREE OF THE BOLTS WERE NON-STANDARD HARDWARE INSTALLED BEFORE THE OPERATOR PURCHASED THE SKIS. THE LIMIT CABLE PREVENTS THE SKI TIP FROM PIVOTING DOWNWARD.
On March 26, 1995, at 1644 Alaska standard time, a wheel/ski equipped Helio H700, N4059H, experienced a gear collapse at Deadhorse Airport, Deadhorse, Alaska. The airplane was being operated as a visual flight rules (VFR) on-demand passenger flight to Deadhorse, under Title 14 CFR Part 135 when the accident occurred. The airplane, operated by Forty (40) Mile Air, received substantial damage. The certificated airline transport pilot and three passengers were not injured. Visual meteorological conditions prevailed. A VFR flight plan was filed. The flight originated from a remote airstrip in the vicinity of Finn Creek, about 50 miles southeast of Deadhorse, at 1547. The pilot reported that he was departing a snow covered airstrip known as Kemik number 1 near Finn Creek. The airplane was being operated on wheels with the skis retracted. The airstrip is about 850 feet long and the pilot departed to the west in a downslope direction. During the takeoff roll, the right main landing gear ski contacted the snow, slowing the airplane's acceleration and producing a pull to the right. The pilot applied left rudder and left brake pressure to maintain directional control of the airplane. As the airplane began to approach the end of the airstrip, the pilot rotated the airplane; however, the airplane settled slightly and the pilot felt a violent impact. A passenger reported that the right ski mechanism had been torn from the airplane. The upper left door hinge was broken, and the windshield partially separated from its frame. The airplane became airborne and the pilot decided to proceed to Deadhorse where emergency rescue equipment was available. During the touchdown on runway 04, the right main gear collapsed. The right ski mechanism was recovered from the departure airstrip. It was broken and bent downward and aft about mid- span, about 180 degrees. The model 4000 Fli-Lite Ski, is manufactured by Fluidyne, Minneapolis, Minnesota. The tip of the ski is held in place and prevented from pivoting downward by a retention/limit cable. The cable is attached to a bracket that is bolted to the forward, inside edge of the ski. Examination of the 4 bolts that attach the bracket to the ski, revealed that only 1 bolt was an AN509-1/14 that is specified in the illustrated parts list of hardware for the ski. The remaining 3 bolts were non-standard hardware with no identification stamp. All of the bolts displayed bending and shearing with multiple 45 degree fracture planes. The operator reported that the skis were purchased used about 3 years prior to the accident. The limit cable retention bracket had not been changed since being purchased. The skis had accrued about 250 hours of service with the operator. The total time of service is unknown. The last inspection of the skis was during a 100-hour inspection, about 40 hours prior to the accident.
AN OVERLOAD FAILURE OF THE RIGHT MAIN GEAR RETENTION/LIMIT CABLE BRACKET BOLTS AND INSTALLATION OF NON-STANDARD BOLT HARDWARE BY OTHER MAINTENANCE PERSONNEL. THE PILOT'S FAILURE TO ABORT THE TAKEOFF WAS A FACTOR IN THE ACCIDENT.
Source: NTSB Aviation Accident Database
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