One Engine Or Both Engines Were Making “Continuous Sputtering/Backfiring” Sounds

Location: Springfield, TN Accident Number: ERA21LA173
Date & Time: April 5, 2021, 09:50 Local Registration: N5018Y
Aircraft: Piper PA-23-250 Injuries: 2 Serious
Flight Conducted Under: Part 91: General aviation – Instructional

On April 5, 2021, about 0950 central daylight time, a Piper PA-23-250, N5018Y, was destroyed when it was involved in an accident near Springfield, Tennessee. The flight instructor and the commercial-rated student pilot were seriously injured. The instructional flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91.

The flight was operated by Highland Rim Aviation, LLC, and the purpose of the flight was to conduct multi-engine training in the twin-engine airplane. The local visual flight rules instructional flight departed from Springfield-Robertson County Airport (M91), Springfield, Tennessee about 0947. According to witnesses, their attention was drawn to the airplane during its takeoff roll from runway 22 due to its “unusual” sound that was inconsistent with takeoff power. One witness said he could not discern if one engine or both engines were making “continuous sputtering/backfiring” sounds. He said the “obviously abnormal sound drew the attention of many of us out to observe the airplane struggle into the air.” The witness, an airline transport pilot and airframe and powerplant mechanic, stated the airplane “didn’t climb much above 100[ft] agl” while on runway heading and that the landing gear remained extended until the departure end of the runway. Shortly thereafter, the airplane entered a shallow turn to its left until the airplane disappeared behind a tree line.

Another witness described “popping, sputtering, and crackling noises” and said that the airplane was “clearly struggling to climb” when it disappeared from her view.

A preliminary review of Automatic Dependent Surveillance-Broadcast (ADS-B) and radar data provided by the Federal Aviation Administration (FAA) revealed that the airplane departed from runway 22. The airplane achieved a groundspeed of 86 knots about midfield, and once off the ground, slowed, and then never achieved a groundspeed above 80 knots. The track depicted a shallow climb for about 1 mile, where about 200ft agl the track depicted a descending, decelerating turn to the left. The radius of the turn tightened until the last target was recorded in the vicinity of the accident site, about ground level, at 59 knots groundspeed.

The airplane was examined and photographed by two FAA aviation safety inspectors. Examination of the photographs revealed that the cockpit and cabin areas were destroyed by impact and came to rest inverted. The wings were mostly separated but remained attached by cabling and sheet metal. The engines were in their nacelles, and the propeller blades of the left engine appeared undamaged and in what approximated a feathered position. The propeller blades of the right engine displayed similar twisting, bending, leading edge gouging, chordwise scratching and tip curling.

The airplane and its engines were recovered from the accident site and retained for further examination.

FMI: www.ntsb.gov