History of Flight
On June 2, 2008, about 1705 eastern daylight time, a Cessna 421C, registration N49DD, was substantially damaged during an attempted takeoff from Pitt-Greenville Airport (PGV) in Greenville, North Carolina. During the takeoff roll, at a speed of about 90 knots, the landing gear retracted and the airplane settled onto the runway. Visual meteorological conditions prevailed, and no flight plan was filed for the flight destined for Wilmington International Airport (ILM), Wilmington, North Carolina. The flight was conducted under 14 Code of Federal Regulations Part 91 as an executive/corporate flight.
The pilot reported that while taxiing for departure, the "Hydraulic Flow" light remained illuminated at a higher than normal engine rpm. He returned to the ramp for a mechanic to investigate. The mechanic stated it was "probably a sensor problem" and noted the hydraulic reservoir was full. The pilot then restarted the left engine (the only engine shut down during the inspection) and taxied back for departure. During the takeoff roll, the pilot heard a loud bang. The nose dropped, he applied back pressure, then the right wing dropped followed by the left wing. The airplane settled onto the runway, slid on the underside of the fuselage, and stopped on the right edge of the runway pavement.
Injuries
The pilot received no injuries. The passenger, seated in the right cockpit seat, sustained minor injuries to his right leg when struck by a fragment from the right engine propeller.
Personnel Information
The pilot, age 66, held an airline transport pilot certificate with ratings for airplane single- and multi-engine land, and instrument airplane. His most recent second-class medical certificate was issued July 12, 2007. He reported 10,573 total flight hours, with 2,713 hours in the accident make and model, and 10,400 hours as pilot in command. His most recent biennial flight review was completed October 28, 2007.
Aircraft Information
The 1976 Cessna 421C was a pressurized, eight-seat, multi-engine airplane with retractable tricycle landing gear. It had accrued 5,566.3 hours time in service. Power was provided by two 375-horsepower Teledyne Continental Motors GTSIO520L engines. The left engine had 1,959.6 hours, with 773 hours since major overhaul; the right engine had 3,827.5 hours, also with 773 hours since major overhaul. Each engine drove a controllable pitch McCauley propeller. The maximum certificated gross weight was 7,450 pounds; the weight at the time of the accident was approximately 7,000 pounds. The most recent annual inspection was completed October 3, 2007, at which time the airframe had 5,355.8 hours, and each engine had 195.8 hours since overhaul. On the day of the accident, maintenance records documented oil and filter changes for both engines and replacement of the alternator on the right engine.
Meteorological Information
The recorded weather at PGV at 1701 included wind from 010 degrees at 4 knots, visibility 7 miles, clear skies, temperature 28°C, dew point 7°C, and an altimeter setting of 29.96 inches of mercury.
Wreckage and Impact Information
The airplane came to rest on the right edge of runway 2. Damage was limited to the propeller tips, skin on the underside of the fuselage, and a penetration of the pressure vessel on the right side near the right cockpit seat. After initial examination, the airplane was lifted from the runway, loaded onto a trailer, and taken elsewhere. When lifted from the trailer, the landing gear was manually extended and secured.
Tests and Research
An FAA inspector and a mechanic inspected the airplane. The landing gear safety switch, installed on the left torque link, had 5/16 inch (approximately 0.31 inches) clearance between it and the striker plate when the airplane's weight was on the landing gear. The Cessna 421 Service Manual specified limits of 0.30 to 0.35 inches for this dimension.
A test of the landing gear warning horn system was conducted. With electrical power on, the gear handle in the "UP" position, and weight on the landing gear, the gear horn did not sound with any throttle or flap position combination. The design specified that the horn should sound when flaps were selected to 16 degrees or greater, or when the throttle lever was reduced to a predetermined point. The condition of the warning system circuit breaker was not reported.
Movement of the torque link assembly from a "weight on wheels" to a "weight off wheels" position resulted in a sound from the safety switch when relays activated.
The landing gear actuators incorporated a mechanical latching mechanism to lock the gear down. Hydraulic release of this latch requires the cockpit gear lever in the "UP" position and the torque link safety switch in a "weight off wheels" position.
The inspection revealed no preimpact deficiencies with the landing gear and associated systems.