Incident Overview
On February 22, 2021, about 1145 eastern standard time, a Cessna 421C, registration N84HA, was substantially damaged during an accident at St. Marys Municipal Airport (OYM), St. Marys, Pennsylvania. The airline transport pilot sustained minor injuries, while the two passengers were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a corporate flight.
Approach and Landing
The pilot reported that while inbound to OYM, the automated weather observing system indicated cloud conditions of 600 ft broken and 1,000 ft overcast, with visibility 1.5 miles in snow. Air traffic control cleared the flight for the GPS approach to runway 28 and provided NOTAMs regarding an inoperative remote communications outlet and several lighted obstructions (towers) near the airport. The pilot had reviewed these NOTAMs before departure.
During the approach, the pilot observed ground contact and, just before reaching minimum descent altitude, sighted the approach lights. After overflying the approach lights, he could see the runway outline. Following touchdown, the airplane struck a snow berm located on the left side of the runway.
Accident Site Examination
Ground scars in the snow were found left of the runway edge, starting approximately 1,000 ft from the approach end of runway 28. The marks extended about 250 ft along and through a snow berm on the left side. The airplane came to rest at the end of the snow marks, oriented on a magnetic heading of about 130°, roughly 210° rotated from the runway 28 heading. At the time of the accident, the runway was covered in an estimated 3-4 inches of snow. Runway edge lights and runway end identifier lights were buried beneath the snow.
Aircraft Damage
Examination revealed bending and displacement of the forward pressure bulkhead, buckling of the floor just forward of the pressure bulkhead, and slight displacement of the left wing from the fuselage at the wing root.
Pilot and Airport Communication
The pilot had contacted airport officials the day before, advising of his planned arrival and understanding that the runway would be plowed prior to his arrival. After the accident, he learned that the airport snowplow had become stuck while plowing a side road adjacent to the airport.
NOTAM Status
A review of Federal Aviation Administration (FAA) records showed no NOTAMs regarding snow on the runway, obscured runway lights, or other field conditions before the accident. The airport manager, relatively new in his position, had not been authorized to issue NOTAMs. Following the accident, he coordinated with the FAA to be placed on the list of authorized NOTAM issuers.
Weather Conditions
The 1135 weather observation at OYM reported clouds broken at 700 ft and overcast at 1,100 ft, with visibility 0.5 mile in light snow. The three previous observations (1035, 1055, 1115) also reported visibility 0.5 mile in snow or light snow.