Accident Overview
On July 28, 2018, about 1225 central daylight time, a Piper PA-28-140 airplane, registered as N624FL, was substantially damaged when it struck transmission lines near Columbia, Illinois. The pilot and two passengers sustained serious injuries, while one passenger received minor injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Departure and Witness Observations
The airplane departed runway 3 at Sackman Field (H49) en route to Alton, Illinois. Witnesses reported to the responding Federal Aviation Administration (FAA) inspector that the aircraft climbed at a shallower than normal attitude after takeoff. It appeared to level off as it continued away from the airport, then contacted transmission lines approximately half a mile from the departure end of the runway.
Postaccident Examination
An FAA inspector performed a postaccident examination of the airframe and found no anomalies that would have precluded normal operation. However, the engine examination revealed fouled spark plugs in the No. 2 cylinder. A compression check of all cylinders showed low compression on each:
- No. 1 cylinder: 50 psi
- No. 2 cylinder: 19 psi
- No. 3 cylinder: 52 psi
- No. 4 cylinder: 50 psi
Further borescope and visual inspection of the No. 2 cylinder did not detect the reason for its low compression.
Manufacturer Guidance
Lycoming Service Instruction 1191A states that if the pressure reading for all cylinders is equal and above 70 psi, the engine is satisfactory. Readings less than 65 psi indicate wear, and subsequent checks should be made at 100-hour intervals. Below 60 psi, removal and overhaul of the cylinders should be considered. It also notes that low pressure in a single cylinder is indicative of air passing by the piston or valve.
Weight and Balance
A weight and balance calculation, based on occupant weights obtained by first responders and verified by the pilot, indicated that the airplane was near its maximum gross weight at the time of the accident.