PIPER PA-24-250 — Astoria, OR

What happened

According to the flight instructor, the student pilot called him while en route during a solo cross-country instructional flight and reported observing an electric current discharge of 10 amperes on the amp meter. The pilot also reported hearing a pulsating tone on the radio. During a subsequent call to the instructor, the student reportedly stated that the airplane had experienced a total electrical failure. The instructor said that he advised the student to immediately extend the airplane's electrically activated landing gear while the airplane still had remaining battery power. During the next hour, the student called his instructor four additional times and a pilot acquaintance three times. Both the instructor and the acquaintance reported that the student sounded extremely disturbed and anxious about the ongoing situation during these calls.

The instructor was located at the home airport when the student flew overhead between about 800 and 1,000 feet above the ground, and he observed that the airplane's landing gear appeared to be extended only halfway. He advised the student to climb to 3,000 feet, and he then instructed the student in detail on how to extend the landing gear using the emergency extension procedure. The instructor estimated that the student flew in the vicinity for about 45 minutes until he stated, “I’ve got it,” which he thought meant that the gear was down and that the student intended to land. The instructor then lost track of the airplane as it flew away from his line of sight. Minutes later, he heard emergency vehicle sirens in the distance.

A witness observed the airplane rapidly descending until his view of it was obscured by intervening terrain or vegetation as it approached ground level. The witness said that the airplane was descending with its nose pointed nearly straight down and that it was turning (rolling about its longitudinal axis). He reported that no fire or smoke was trailing from the airplane.

The wreckage signatures and ground scar evidence were consistent with a stall-spin type accident sequence and an impact with the ground at a 45-degree nose-down angle. The landing gear was found in the down-and-locked position. No preimpact mechanical malfunctions or failures were found with the airplane control systems or engine that would have precluded normal operation. The electrical generating and storage components were removed for examinations and tests. Impact damage precluded functional tests of the alternator, over voltage relay, and spike guard capacitor; however, the units passed electrical continuity checks. An output wire on the alternator was found half severed, with the ends of the strands oxidized, indicating a preexisting condition. However, the electrical component examinations could not determine the failure mode of the charging system.

It is likely that the student pilot remained distracted by the reported failure of the electrical power system and failed to maintain airspeed while preparing for landing, which resulted in the subsequent stall/spin to ground impact.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.