History of Flight
On July 18, 2023, at about 0904 mountain daylight time, a Cessna T310R, registration N5251C, was destroyed in an accident near Santa Fe, New Mexico. The pilot was fatally injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Air traffic control tower communications indicated that the controller cleared the pilot for takeoff from runway 20, reporting calm wind. The pilot acknowledged. ADS-B data showed the takeoff roll began about 0901. At about 0903, the pilot transmitted, “51C’s got an engine failure.” The controller asked for a repeat, and the pilot restated the message. The controller cleared the pilot to make a left turn to runway 33, which the pilot acknowledged. About seven seconds later, the controller advised the pilot he was cleared to land on any runway; the pilot responded that he was “going to get some altitude.” The controller then asked the pilot to confirm one engine, and the pilot replied “one engine.” No further transmissions were received from the pilot.
ADS-B data showed that after takeoff the airplane drifted left of the runway but generally maintained runway heading for about 1 mile, climbing to a maximum altitude of about 6,425 ft mean sea level (msl), or about 200 ft above ground level (agl). After about 1 mile, the airplane turned slightly left and continued south for about another mile, maintaining altitude until 0902:37, when it began a slow descent at about 101–102 knots ground speed. Around 0902:56, the airplane entered a left turn while descending at a greater rate. The last ADS-B data point, recorded at 0903:37, placed the airplane over a gulley at an undetermined altitude, at 86 knots, on a track of 044°, about 150 ft southwest of the accident site. The airplane was aligned with an alley oriented 044° magnetic.
Witnesses traveling westbound on Interstate 25 reported seeing the airplane flying eastbound with a nose-up attitude at low altitude, the left propeller not rotating, and the landing gear retracted. The driver stopped as the airplane passed. The airplane appeared to be in a left bank, then the wings leveled as it cleared a ravine. The left wing impacted a house, and the airplane spun around. Another witness nearby reported that the airplane’s left wing and tail dropped but not more than 45° before striking the south side of the house.
A dashcam video taken less than half a mile from the accident site corroborated the ADS-B data and witness accounts, showing the airplane at low altitude, descending in a nose-high attitude heading south toward Interstate 25 and a frontage road, then turning about 90° left. The wings leveled before the airplane exited the camera view at extremely low altitude.
Personnel Information
The pilot’s personal logbooks were not recovered, and details of his recent and past experience were unavailable. Friends described him as having excellent knowledge and experience with multi-engine airplanes, including war birds, float planes, and helicopters. One friend characterized his engine management as fantastic, and another described him as one of the most qualified pilots they had ever known.
Aircraft Information
On the day of the accident, the pilot requested that the airplane’s four tanks be topped off, purchasing 60.6 gallons of 100 low lead fuel. The airplane was equipped with optional 63-gallon auxiliary fuel tanks. Weight and balance information was in the airplane but lost in the postaccident fire.
Performance calculations, given the environmental conditions, an empty weight of 3,942.8 lbs, 978 lbs of fuel (63-gallon auxiliary tanks), a 200-lb pilot, and 10 lbs of baggage, indicated a predicted one-engine inoperative climb rate of about 300 ft per minute at a gross weight of 5,130.8 lbs.
Meteorological Information
The automated weather observation at Santa Fe Municipal Airport recorded variable wind, 10 statute miles visibility, clear skies, temperature 26°C, dew point 4°C, and barometric pressure 30.30 inches of mercury. Airport elevation was 6,349 ft msl, and density altitude was calculated to be 8,769 ft msl.
Wreckage and Impact Information
The fuselage came to rest upright on the parking area of a private residence. The initial point of impact was likely the southwest corner of a modular house at an elevation of 6,301 ft msl; thermal damage to the house prevented precise determination. A postaccident fire consumed most of the fuselage, including the cockpit. The left side of the fuselage was intact up to about the middle. The left engine exhibited multiple breaches to the case; the left propeller remained attached, with two blades appearing in feather position and exhibiting aft bending, and the third blade straight. The landing gear was found retracted.
Examination of the left engine (TSIO-520-BB23B, serial number 287610-R) revealed a counterweight jammed next to cylinder No. 1. The oil sump contained significant metal debris, including pieces of crankshaft counterweights, counterweight retaining rings, retainer plates, bushings, and a connecting rod cap. The crankcase was split open; two counterweight assemblies between cylinder Nos. 3 and 4 were separated from the crankshaft cheeks. One counterweight between cylinder Nos. 1 and 2 remained attached; another was partially separated and wedged against the crankcase. The retaining ring ears on the attached counterweight were oriented approximately 180° from the crankshaft centerline on the aft side, while forward-facing rings oriented toward the centerline. One aft retaining ring was installed with the sharp edge outboard, while the other was incorrectly installed flipped over with the sharp edge inboard.
The right engine (TSIO-520-BB24B, serial number 287609-R) was examined; Nos. 1 and 3 cylinders were removed. Its counterweight retaining rings were oriented correctly (aft-facing rings 180° from centerline, forward-facing toward centerline). No mechanical malfunctions or failures were found that would have precluded normal operation.
A review of engine maintenance logbooks showed both engines were overhauled in October 1998 and installed on April 29, 1999. Logbook entries dated May 27, 1999 (1.1 hours after overhaul) indicated that Nos. 1 and 3 cylinders were removed and the dampers (counterweights) were removed to comply with Teledyne Continental Motors (TCM) Airworthiness Directive AD 99-09-17, later superseded by AD 99-19-01 (September 15, 1999). On October 1, 2009, both engines underwent top overhauls with replacement of all cylinders at 665.2 hours since major overhaul. The time from AD 99-09-17 maintenance to the last annual inspection (July 13, 2023) was calculated to be 1,162.3 hours. Damage to instruments precluded further engine hour calculations beyond that inspection.
Additional Information
TCM Mandatory Service Bulletin MSB 99-3C, revised July 27, 1999, called for removal of two cylinders, two connecting rods, and all counterweights to facilitate visual and ultrasonic inspection of the Nos. 2 and 5 crankshaft cheeks. MSB 99-3C identified the accident engines (by serial number) as applicable. The bulletin stated installation specifications: “INSTALL SNAP RINGS TOWARD THE CRANKSHAFT CENTERLINE AS SHOWN,” “INSTALL SNAP RINGS WITH SHARP EDGE (FLAT SURFACE) FACING OUTBOARD,” and “MINIMUM GAP BETWEEN SNAP RING EARS = 0.179 INCH.”
The FAA Airplane Flying Handbook notes that, on twins with conventional clockwise-rotating engines as viewed from the pilot seat, the critical engine is the left engine.
An autopsy of the pilot conducted by the Office of the Medical Investigator, University of New Mexico, listed the cause of death as blunt force injuries.