Flight History
On October 25, 2018, about 1119 eastern daylight time, a Piper PA-31T, N555PM, was presumed to have impacted the Atlantic Ocean about 100 miles southeast of Charleston, South Carolina. The two pilots and three passengers were not found and presumed fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The airplane departed from its home base, a private runway in Andrews, South Carolina, destined for Governors Harbour Airport (MYEM), Governors Harbour, Bahamas. Radar and air traffic control data showed the airplane departed toward the southeast about 1047. It crossed over the coastline and began a climb to an assigned altitude of 25,000 ft. The climb rate was consistent at 500 ft per minute, and the airplane remained on course.
When the airplane was about 12 miles from the assigned fix (about 95 miles southeast of Charleston Air Force Base/International Airport), while climbing through 24,300 ft, the pilot made a garbled radio transmission with increased background noise that included the word "emergency." Another pilot relayed that he heard N555PM say he was diverting to CHS. The airplane then began a descent about 1,000 fpm and returned on course. About 23 seconds after the garbled transmission, the pilot stated, "we're descending." About 15 seconds later, at about 23,500 ft, the airplane turned sharply left, and the descent rate increased to greater than 4,000 fpm. About 25 seconds later, radar altitude became invalid; last reported altitude was 21,500 ft. At 1118:33, the pilot transmitted "emergency emergency," and no further transmissions were recorded. The last radar position at 1118:50 was about 3 miles left of course, about 100 nautical miles east southeast of CHS.
A search was conducted by the U.S. Coast Guard. One search airplane reported an oil sheen near the last known coordinates; however, neither the airplane nor debris were located. A commercial tanker briefly observed a white object beneath the water surface about 4.5 miles east of the last radar position, but it could not be identified. The search was cancelled 2 days later at sunset.
Personnel Information
The airplane was certificated for single pilot operation. The second pilot on board, who also held a flight instructor certificate, was serving as co-pilot.
Aircraft Information
The airplane's most recent annual inspection included routine maintenance, replacement of starter generators on both engines, replacement of the cabin oxygen bottle, and compliance with airworthiness directive inspections, including AD 2017-02-06 addressing potential electrical wiring arcing and fire risk. The airplane was equipped with an airframe and propeller deicing system, an autopilot, airborne weather radar, and a satellite-based weather data receiver.
Meteorological Information
Weather records indicated no convective or precipitation echoes in the area at the time. Satellite imagery showed a mid-level layer of clouds with tops estimated at 15,500 ft. An AIRMET advisory for moderate turbulence was in effect. Atmospheric model results characterized the atmosphere as stable, with a freezing level around 13,000 ft. Icing conditions were likely between the freezing level and the estimated cloud tops. A shallow layer favorable for light rime icing was present at 23,000 ft. Pilot reports indicated light to moderate turbulence.
Communication Details
At the time of the pilot's initial emergency transmission, the ATC audio recording included the sound of an emergency locator transmitter (ELT) homing signal, obscuring the pilot's voice. The only intelligible portion was the call sign and "emergency." The pilot's intention to return to CHS was overheard by another pilot and relayed to ATC.
The ATC recording mixed all frequencies into a single channel, making it impossible to isolate the pilot's voice from the ELT signal. Filtering failed to enhance intelligibility. The ELT signal was recorded intermittently from 1039 until 1124. It was present for seconds or fractions of a second, with gaps from fractions of a second to minutes. The signal was captured only on the recording of the R52 controller position at Jacksonville Center, not on the earlier R71 position. The type of ELT installed on the accident airplane was not recorded in available records.