History of Flight
On August 17, 2011, at 0805 central daylight time, a Cessna 310Q, registration N444YM, owned by Hamilton Air LLC and operated by an individual, impacted a main road and struck a tree in a residential area during the initial takeoff climb at Tupelo Regional Airport (TUP), Tupelo, Mississippi. The pilot was fatally injured and the airplane sustained substantial damage. Visual meteorological conditions prevailed and no flight plan was filed for the personal local flight conducted under 14 CFR Part 91.
The airplane had just undergone an annual inspection. The number two cylinder on the left engine was replaced due to low compression. A ground run-up of both engines was performed as part of the post-maintenance check. The pilot/owner requested 15 gallons of aviation fuel prior to the first flight after inspection.
Local authorities reported the airplane was cleared to depart from runway 36 with an easterly departure. Witnesses observed the airplane roll down the runway and lift off. At an estimated altitude of 300–500 feet above the runway, about midfield, the airplane turned left on a west heading as it descended. Witness statements disagreed: some heard engines lose power, others heard the engines operating at low power. The airplane flew in a level attitude under electrical power lines, over the airport perimeter fence, and impacted the adjacent main road, separating all three landing gear. A vehicle on the road was struck by airplane debris. The airplane continued forward until the left wing outer section impacted a tree, separating a four-foot section of the outer left wing. The nose section then impacted the base of a 3-foot diameter tree in a front yard. No communication occurred between the pilot and controller after takeoff clearance, and no distress calls were heard.
Personnel Information
The 69-year-old pilot held a commercial pilot certificate with ratings for airplane single-engine and multi-engine land, and instrument airplane. He was issued a second-class medical certificate on August 18, 2010, with a limitation requiring corrective lenses. He documented 2,740 total hours at that time. His flight logbook was not located after the accident, and the date of his last biennial flight review could not be determined.
Aircraft Information
The Cessna 310Q (serial number 310Q0958) is a six-place, all metal, low-wing, multi-engine airplane with retractable landing gear, manufactured in 1974, and issued a standard airworthiness certificate in the normal category. It was powered by two Continental IO-470-VO, 260-horsepower engines equipped with McCauley model 3AF32C87-QR/S82NC-4, three-bladed, variable-pitch propellers. The last annual inspection was August 16, 2011, at a total time of 3,382.1 hours. The left engine had 710.8 hours since overhaul, and the right engine had 652.2 hours since overhaul.
Airport Information
Runway 36 at TUP is asphalt/grooved, 6,502 feet long by 150 feet wide, at an elevation of 346 feet mean sea level. North of runway 36 is an unobstructed field within the airport property.
Meteorological Information
The nearest official weather observation at TUP at 0753 was: wind calm; visibility 10 statute miles; sky clear; temperature 24°C; dew point 20°C; altimeter 30.09 inches of mercury.
Wreckage and Impact Information
Examination of the crash site showed initial contact with the road left impact marks consistent with propeller blade strikes and tire marks. The airplane came to rest on a heading of 290 degrees. The nose, cockpit, and cabin area were crushed aft to the middle seat row. The instrument panel was compressed aft to the aft wing spar. A four-foot section of the outboard left wing, including the fuel tip tank, separated and came to rest about 10 feet ahead and to the left of the main wreckage. The remaining left wing was displaced forward, separating from its aft wing-to-fuselage attachment point. The left engine with propeller remained attached to the left wing structure. The right wing remained attached to the fuselage with impact damage. The right engine separated from its mounting points but remained attached by supply lines. The right propeller separated from the engine crankshaft flange and was found about 40 feet ahead of the main wreckage, impacting the ground and an exterior house wall before coming to rest.
The fuselage from the middle seat area and empennage remained intact with impact damage. All three landing gear separated from their attachment points and came to rest behind the main wreckage. All fuel cells were breached. Flight control continuity was established, with all damage consistent with impact. The left and right fuel selector valve positions could not be determined due to impact damage. Evidence of aviation fuel was present, and several gallons were recovered during wreckage recovery.
Examination of the left engine showed the B-nut on the fuel supply hose to the fuel manifold valve on top of the engine was backed off about a quarter turn, and the anti-tamper putty was broken.
Medical and Pathological Information
The Mississippi State Medical Examiner's Office conducted a postmortem examination; the cause of death was multiple blunt trauma. FAA CAMI toxicology tests were negative for carbon monoxide, cyanide, and ethanol, and positive for Rosuvastatin in the urine.
Test and Research
A teardown examination of both propellers revealed no indication of failure prior to impact. The left propeller was rotating at low power or windmilling in a low pitch position at impact. The right propeller was rotating at a high power level in a low pitch position at impact.
With Safety Board oversight, both engines were test run at the manufacturer's facility. Both engines produced rated power and showed no abnormalities that would have prevented normal operation. After the left engine test run, the manifold valve fuel supply hose B-nut was set at finger-tight torque. A wire was attached to loosen the B-nut during engine run. With a stop limiting rotation, the engine was started at full throttle and the B-nut loosened to slightly over a quarter turn; this was repeated. When the B-nut was loosened, the engine immediately lost power and shut down, sometimes backfiring.
In an interview, the mechanic who performed the number two cylinder replacement stated that the fuel supply hose B-nut to the manifold valve was removed to facilitate the cylinder replacement. He said the B-nut was torqued at reinstallation, but he did not have anti-tamper putty to mark it.
The airplane's Owner's Manual, Section III, Emergency Procedures, Engine Inoperative Procedure, provides instructions on managing an engine failure prior, during, and after takeoff.