Aviation Accident Summaries

Aviation Accident Summary ERA20FA056

Headland, AL, USA

Aircraft #1

N663SF

Bell 407

Analysis

According to the flight nurse and paramedic, the flight was normal until the helicopter suddenly rolled to the left as they approached the helipad during landing. The pilot made no attempt to correct the roll, and the helicopter rolled onto its side and the main rotors contacted the ground. The pilot was immediately observed to be unresponsive and not breathing, and the flight nurse and paramedic began CPR as quickly as they could extricate the pilot from the cockpit. Autopsy of the pilot revealed severe coronary artery disease that placed him at significant increased risk for sudden death from an acute coronary event. Given the pilot's sudden inability to pilot the helicopter safely, the recognition by certified medical personnel that he was unresponsive and not breathing immediately following the accident, and the fact that he did not suffer enough blunt force trauma to have caused immediate cardiac arrest, it is most likely that the accident occurred because the pilot became incapacitated from an acute cardiac event.

Factual Information

HISTORY OF FLIGHTOn December 25, 2019, about 1713 central standard time, a Bell 407 helicopter, N663SF, sustained substantial damage when it was involved in an accident near Headland, Alabama. The commercial pilot was fatally injured, and the flight nurse and paramedic were not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 135 air ambulance flight. According to the flight nurse, who was seated in the aft right seat, the crew were responding to an accident when the call was cancelled enroute and they turned back to their base. The flight nurse described the flight as normal, and stated that the helicopter was "working beautifully." He said that the pilot approached the helipad slightly faster than normal. As the helicopter neared the helipad, it made an abrupt "roll" to the left. The pilot did not say anything and did not correct for the roll. The helicopter impacted terrain and came to rest on its left side. The flight nurse stated that he and the flight paramedic unbuckled their restraints, exited the helicopter from the aft right door, and immediately tended to the pilot. The flight nurse said his first instinct was that the pilot had some sort of cardiac event. Using his flashlight, he could see that the pilot's face was blue, he was not breathing, and was unresponsive. The engine was still running, so another pilot (who witnessed and responded to the accident) performed an emergency shutdown, and all three of them pulled the pilot out of the helicopter from the windshield and initiated cardiopulmonary resuscitation (CPR). The flight paramedic stated that, about 10-15 ft above the ground, the helicopter rolled 45° to the left. The flight paramedic said, "It felt if no correction was made and [the helicopter] continued to the ground. I could hear rotors striking the ground." When the helicopter stopped moving, he and the flight nurse exited the aft right door. The engine was still running so it was shut down. The pilot, who was unconscious and not breathing, was pulled from the helicopter and immediately administered CPR. A witness, who was also a helicopter pilot, saw the accident helicopter making a "shallow approach" to the helipad. He turned his attention away for a moment, but when he looked back at the helicopter, it had impacted the ground and he could see "flying debris and water from the nearby pond." PERSONNEL INFORMATIONThe pilot was hired by Viking, LLC, on December 2, 2019, and completed training on December 6, 2019. He completed his first 7-day "hitch" with Survival Flight, Inc. between December 10 -17, 2019, then had 7 days off. The day of the accident was the pilot's first day starting his second 7-day "hitch." The operator stated that the pilot's normal duty hours were 0700 to 1900. He flew one flight on the day of the accident before the accident flight. Both the flight nurse and paramedic stated that flight was normal, and they did not observe any medical issues with the pilot prior to the accident flight. The pilot was in a good mood and had not expressed any issues with stress or fatigue. WRECKAGE AND IMPACT INFORMATIONThe helicopter impacted level, soft grass about 120 ft west-northwest of the helipad. It came to rest on its left side on a heading of about 103° in about 3 to 6 inches of standing water from recent rainfall. There was no postimpact fire. Examination of the helicopter revealed that all four main rotor blades had separated from the main rotor at the hub and came to rest adjacent to the wreckage. All four blades exhibited extensive impact damage and pieces of composite blade material were strewn around the wreckage area. The left skid was displaced inward. The fuselage sustained minor damage and all occupied seats remained securely attached to their respective floor fittings. The pilot's four-point seatbelt/shoulder harness was securely attached to the airframe and was found unbuckled, but when manually tested, it functioned normally. The inertial reel also functioned normally (locked) when tested. Both the flight nurse and paramedic’s three-point seatbelt/shoulder harness (inertial reel) systems were secure to their respective airframe attach points and functioned normally when tested. No mechanical issues were noted with the seats or restraint systems. The tail boom was fractured about 12 to 15 inches aft of the tail boom-to-fuselage attachment point. The tail rotor drive shaft was severed in three locations due to impact; however, continuity was established to the tail rotor. The tail rotor gearbox and both blades were intact, but one blade exhibited some impact damage. The gearbox chip detector was absent of debris. The right stabilator was undamaged and the left hand stabilator sustained impact damage. The top vertical fin exhibited minor leading-edge impact damage. Flight and engine control continuity were established for the engine, main rotor, and tail rotor system, by manual manipulation of the anti-torque pedals, collective and cyclic in the cockpit. No mechanical issues were observed that would have precluded normal operation at the time of impact. Examination of the engine revealed that it was secure to its respective mounts and did not sustain any impact damage. There was evidence of engine and drive train rotation at the time of impact and continuity was established for both N1 and N2 rotors. The upper and lower chip detectors were removed and absent of ferrous metal debris. The helicopter was equipped with an engine control unit (ECU), which was removed and downloaded. The ECU data indicated the engine was performing normally prior to the accident sequence. All relevant engine parameters (torque, Ng/Np speeds, fuel flow, and temperature) were normal prior to the accident and responded as expected during the accident sequence. No mechanical issues were observed with the engine that would have precluded normal operation at the time of impact. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the pilot was conducted by the Alabama Department of Forensic Science, Montgomery, Alabama. The cause of death was determined to be hypertensive and arteriosclerotic cardiovascular disease complicated by blunt force injuries and the manner of death was accident. The pilot's heart was enlarged at 510 grams (average for a man of his weight is 367 gm with a range of 278-484 gm). In addition, coronary artery disease, including 70%-80% stenosis of the left main, 80-90% stenosis of the left anterior descending, 70-80% stenosis of the circumflex, and 40-50% stenosis of the right coronary, was identified. Wall thickness was not described. The visual inspection of the heart muscle was unremarkable; histology was not performed. In addition, the pathologist reported the presence of hypertensive cardiovascular disease based on the appearance of the kidneys. Toxicology testing performed by the Alabama Department of Forensic Sciences identified only naproxen in femoral blood. Naproxen is a mild anti-inflammatory analgesic available over the counter and often marketed with the names Naprosyn and Aleve. It is not considered impairing. Toxicology testing performed by the FAA's Forensic Science Laboratory identified lansoprazole, ranitidine, and lidocaine in femoral blood and liver tissue. Dexlansoprazole is metabolized to lansoprazole and is used to treat GERD. It is often marketed with the name Dexilant and is not considered impairing. Ranitidine is an over-the-counter medication also used to treat symptoms of heartburn; it is commonly marketed as Zantac and is not considered impairing. Lidocaine is an anesthetic and available over the counter in patches, gels, or creams for topical use of local pain. Used this way, it is not considered impairing. When used intravenously, lidocaine is also an anti-arrhythmic drug that may be used in the treatment of cardiac arrest.

Probable Cause and Findings

Pilot incapacitation by a sudden cardiac event related to severe coronary artery disease, which resulted in a loss of helicopter control.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports