\u201cDense dust\u201d blown into the cabin as the helicopter entered a five-foot hover over a soccer field caused the pilot to lose visual contact with the ground, according to a preliminary report issued by Papua New Guinea\u2019s Accident Investigation Commission (AIC). All four passengers suffered serious injuries, and one person on the ground was killed when the aircraft drifted backwards and hit a tree. The pilot, loadmaster, and several locals reported minor injuries.<\/p>\n
The AIC reported that the pilot of the charter flight from the Sengapi Airstrip was a PNG native with 11,600 hours of flight experience but unfamiliar with the area. The helicopter\u2019s GPS did not contain coordinates for their destination, so he used the nearest available fix and relied on a passenger to aid him in navigation. After crossing the airstrip, he made a shallow approach to the soccer field where villagers were waiting.<\/p>\n
In a brief initial report, the Australian Transport Safety Bureau (ATSB) stated that one passenger was seriously injured and the airplane sustained substantial damage during a forced landing. The pilot initiated the forced landing after observing \u201can engine malfunction\u201d during the initial climb. The purpose of the flight and total number on board were not initially disclosed.<\/p>\n
\u201cThe pilot\u2019s decision to continue the visual flight rules flight into deteriorating weather conditions during a dark night and over unlit terrain\u201d led to spatial disorientation that ended in the crash that claimed the lives of all three on board, the National Transportation Safety Board (NTSB) said.<\/p>\n
Two company pilots were onboard the Part 135 charter flight transporting a client to \u201clook at properties\u201d in southern Georgia and northern Florida. They departed Atlanta\u2019s Fulton County Executive Airport at 07:00 that morning; the return flight stopped at the Thomasville (Georgia) Regional Airport, from which they departed at 18:40 after taking on 40 gallons of fuel.<\/p>\n
At 19:37, the passenger responded to a text message from his wife with a photograph showing that they\u2019d made a precautionary landing in a field after a \u201cbad storm pop[ped] up.\u201d He estimated their arrival time at 21:30.<\/p>\n
ADS-B data showed that after lifting off from the field, the helicopter followed power lines north and then back south, then flew to the Perry-Houston County (Georgia) Airport 117 nm to the southeast. It landed there at about 20:15, 10 minutes after the end of civil twilight, and took off again five minutes later, following Highway 75 northwards before crossing into the Piedmont National Wildlife Refuge.<\/p>\n
During the last three minutes of the flight, it \u201cmade a series of left and right turns before entering \u201ca rapidly descending right turn\u201d at a rate that increased to almost 4,000 feet per minute and crashing in a 90-degree right bank. A witness south of the accident site reported \u201cvery rainy\u201d conditions.<\/p>\n
The 2020-model helicopter was equipped with a 10.6-inch Garmin display capable of displaying both primary flight and navigation screens side by side, a Garmin GTN 750xi combined navigation and communication system, and a HeliSAS stability augmentation system, but was not certified for flight in instrument conditions.<\/p>\n
It had been acquired by the operator several months earlier but had not been added to its Part 135 certificate. The 42-year-old, 6,000-hour commercial pilot owned the charter company and held both pilot and instructor certificates for instrument helicopter, but the NTSB was unable to determine his proficiency with the systems in the accident aircraft. The 46-year-old co-pilot listed 383 hours of flight experience. He held a commercial certificate with helicopter and instrument airplane ratings.<\/p>\n
Though the airplane was estimated to be 500 pounds overweight with its center of gravity more than two inches aft of limits, the NTSB attributed its departure crash to \u201cthe pilot\u2019s failure to ensure that his seat was properly secured before initiating the takeoff, which resulted in a loss of control during the initial climb.\u201d<\/p>\n
All four occupants perished when the airplane lifted off about 1,000 feet down Runway 21 of Atlanta\u2019s DeKalb-Peachtree Airport, pitched up and rolled inverted, and crashed nose-first next to the runway. Investigators found the pilot\u2019s seat at the extreme aft end of its track, a position not compatible with his five-foot nine-inch height.<\/p>\n
The 1978-model airplane\u2019s original reciprocating engine had been replaced with a Rolls-Royce 250-B17F\/2 turbine under the provisions of a supplemental type certificate. Slippage of the pilot\u2019s seat is a known hazard in single-engine Cessnas of that vintage and is the subject of both an airworthiness directive (AD 2011-10-09) requiring repetitive inspection of the seat tracks and seat locking pins and a service bulletin (SEB07-R06, most recently revised June 11, 2015) requiring installation of a secondary stop behind the pilot seat and recommending one behind the co–pilot\u2019s seat.<\/p>\n
The Pilot Operating Handbook\u2019s \u201cBefore Starting Engine\u201d checklist also calls for verifying that the seat is locked in place. Maintenance records showed that the AD was last accomplished on July 19, 2021, but the service bulletin was never carried out.<\/p>\n
Imprecise engine cycle tracking by the airplane\u2019s operator resulted in the third-stage turbine wheel remaining in use beyond its service limit, allowing a low-cycle fatigue crack to progress to complete failure.<\/p>\n
Shortly after the parachutists jumped at 14,500 feet, the pilot of the skydiving platform heard a loud bang followed by brief vibrations. Seeing holes in the engine cowling, the pilot diagnosed an uncontained engine failure, pulled the emergency fuel shut-off, shut down the electrical system after broadcasting a MAYDAY, and made a successful power-off landing on Runway 18, at the opposite end of the airport from the drop zone.<\/p>\n
According to the ATSB, \u201cExamination of the engine identified a perforation of the external wall of the combustion chamber, holes through the exhaust assembly, failure of the main shaft and the torsion shaft, and loss of the 2nd- and 3rd-stage turbine wheels.\u201d A teardown inspection by the manufacturer found a fragment of the third-stage turbine wheel lodged in the rupture of the containment case; the remaining pieces of the second- and third-stage turbine wheels were missing, as were the aft turbine bearing and bearing support, aft sump scavenge pump, aft bearing support struts, turbine nut, and tail cone. Examination of the fragment of the third-stage turbine wheel showed evidence of low-cycle fatigue cracking.<\/p>\n
The Honeywell TPE331 engine had been overhauled in June 2009 and was maintained by the same organization until it was removed in September 2019 while the airframe was refurbished. The first- and second-stage turbine wheels were replaced and a hot section inspection performed in August 2014. A new maintainer took over and reinstalled the engine in August 2020. The most recent 100-hour inspection was in February 2022, and the operator had scheduled replacement of all three turbine wheels at an upcoming maintenance appointment.<\/p>\n
A 2006 U.S. airworthiness directive mandated a revised method of counting operating cycles in Honeywell engines to adjust for the number of landings made in specialized operations such as skydiving and crop-dusting. The ATSB\u2019s review found that the operator had logged landings accurately but estimated the daily number of shutdowns based on their pilots\u2019 recollections, leading the maintenance provider to underestimate the third-stage turbine wheel\u2019s number of equivalent cycles by 477.6. This exceeded the manufacturer\u2019s service limit by 357.6.<\/p>\n
The pilot of an EMS helicopter who lost consciousness on a short positioning flight subsequently tested positive for both alcohol and metabolites of cocaine, but the NTSB concluded that those findings alone were not sufficient to account for his \u201csyncopal episode.\u201d Those metabolites included cocaethylene, indicating \u201cthat both cocaine and ethanol had been in his system at the same time, with more than a small amount of cocaine likely used.\u201d The pilot was seriously injured, the flight nurse suffered critical injuries, and the flight paramedic escaped with minor injuries after the pilot lost control. The precise cause of his incapacitation was not determined.<\/p>\n
The helicopter was dispatched from its base to transfer a patient from Andalusia Health Hospital to another facility. The en route portion of the 15-minute flight was uneventful, but as they approached the hospital helipad, the pilot recalled \u201cfeeling sweaty and clammy.\u201d The flight reported that their flight path seemed low as they approached the hospital, and that the flight nurse had tapped the pilot on the shoulder to tell him so.<\/p>\n
After briefly levelling off, the helicopter\u2019s nose dropped again. The flight nurse made a MAYDAY call and told the pilot to \u201cPull up, pull up, pull up.\u201d Witnesses nearby confirmed that the helicopter passed about 300 feet overhead, pitched up at least 90 degrees, and rolled left into trees, power lines, and the ground.<\/p>\n
Investigators found that in a visit to his primary care physician on April 29, 2022, one week after his FAA medical exam, the pilot reported using \u201can oral appliance\u201d to treat obstructive sleep apnea (OSA) since 2015. His history of OSA was never disclosed to the FAA. They also found that he had been convicted for driving under the influence in 2012 and arrested for the same offense in May 2022, but had not reported this to either the FAA or his employer.<\/p>\n