ERA23LA071 · Mooney M20J

The pilot was operating on an instrument flight rules (IFR) flight plan in dark night instrument meteorological conditions (IMC). As the pilot approached the destination airport, the air traffic controller attempted to vector him onto his requested GPS instrument approach procedure. The pilot was provided course corrections and heading changes from the controller, and was advised that the airplane before him had performed the missed approach procedure and diverted due to low cloud ceilings (200 ft above ground level [agl]). Flight track data revealed that the airplane was consistently below published minimum altitudes throughout the approach and was 500 ft below the minimum altitude prescribed at the final approach fix. The pilot continued the descent below the lowest minimums prescribed by the approach procedure, and about 1.25 miles from the runway and left of the runway centerline, the airplane impacted and became suspended in a power line tower at an elevation about 600 ft mean sea level (msl) and 100 ft above ground level. The airport was located at an elevation of 539 ft msl. Examination of the airplane revealed that there were no pre-impact mechanical anomalies that would have prevented normal operation. In an interview following the accident, the pilot stated that his course diversions during the flight were the result of a mis-programmed GPS. Throughout the interview, he could not articulate the features of his IFR-certified GPS, and stated that, in many situations, he used his handheld, VFR-only GPS to avoid the “complex keystrokes needed” to operate the IFR GPS. The pilot stated that he was not receiving vertical guidance on his GPS after intercepting the final approach course. He set an “alarm” to sound when the airplane had descended to 800 ft on the approach, but at 1,200 ft, he sighted the ground, and became focused on “keeping contact with the ground through the side window” and “pulling the airport out of the soup.” The pilot stated that he was familiar with the powerlines that he impacted and believed that he was beyond them. The lowest altitude allowed by the approach procedure was 789 ft msl, or 269 ft agl. However, this altitude was for an approach category that provided both lateral and vertical course guidance, and the pilot stated that he was not receiving vertical guidance. Whether the lack of vertical guidance was the result of the pilot’s mis-programming of the approach procedure or because he was referring to his VFR-only GPS for guidance was not determined. The lowest altitude allowed for an approach with only lateral guidance was 980 ft msl, or 460 ft agl. Based on the available information, the pilot became preoccupied with attempting to visually locate the runway and failed to maintain an effective scan of his instruments, which resulted in his descent below minimums, lateral deviation off the approach course, and collision with powerlines.

Verbatim NTSB analysis and probable cause from the NTSB dataset