Air transportation safety investigation A19P0142

The occurrence

On 24 September 2019, the E & B Helicopters Ltd. Bell 206B helicopter (registration C-GEBY, serial number 3375) was conducting a visual flight rules flight from the operator's base at Campbell River (E & B Heli) Heliport (CCR6) in Campbell River, British Columbia, to Moat Lake, British Columbia, with only the pilot on board.

Shortly after departure, while flying southeast along the coastline, the helicopter briefly levelled off at 615 feet above sea level, then began a descent. When the helicopter was at 417 feet above sea level, it entered a right-hand climbing turn toward land and, following the turn, it began to descend again. During this descent, at 1103 Pacific Daylight Time, control of the helicopter was lost when it was about 200 feet above ground level and the helicopter fell to the ground, striking a building and 2 vehicles. The pilot was fatally injured. No one on the ground was injured. The helicopter was destroyed by the impact forces and a post-impact fire.

The investigation found that an engine power anomaly likely occurred while the helicopter was in cruise flight and, as a result, the pilot reversed course and entered a descent consistent with an autorotation. Following the occurrence, a visual and microscopic examination of the main rotor blades revealed several indications of structural failure in flight. At some point during the flight, both main rotor blades became deformed. Although indications of fatigue were present post-occurrence on a small portion of the trailing edge of one of the main rotor blades, the extent to which this fatigue contributed to the deformation could not be determined. The investigation also found that in the last moments of the flight, likely as a result of the deformed blades, the main rotor rpm decreased to a point that could not sustain autorotational flight, and the helicopter fell vertically and impacted the ground.

The investigation also revealed that the engine fuel system did not have the appropriate accumulators and double check valve for the Bell 206 helicopter. During the installation of the engine, the company maintenance control system was ineffective at ensuring that the engine installation complied with the manufacturer’s recommendations, including having the correct accumulator and double check valve configuration for the Bell 206. If maintenance procedures do not include a thorough review of all related instructions and bulletins, there is a risk that an aircraft will be released into service in a non-airworthy configuration.

The investigation examined the air operator’s safety culture. Safety culture within a company can be summarized as “how we do things around here.” The pilot was the company’s owner, accountable executive, and operations manager, and direction on how the maintenance department was to respond to a partial loss of engine power that occurred a week before the occurrence came from him. The investigation revealed that many operational and maintenance-related decisions were being made based on a single opinion, rather than a process of validation by a hierarchy of independent and skilled supervisors. In addition, several opportunities to improve the safety of the flight had been missed. If company management routinely deviates from regulatory requirements, there is an increased risk that an unsupportive safety culture will develop, affecting the entire organization.

The investigation examined the certification process of composite main rotor blades. A structural fatigue test, completed as part of the primary structural element threat assessment, is intended to ensure the continuing airworthiness of a structural component, the failure of which could be catastrophic. A dynamic load assessment helps determine the maximum damage size to be introduced into the structural fatigue test specimen. The investigation determined that no dynamic assessment was carried out for the certification of the model of Van Horn composite blades installed on the occurrence helicopter. If data from a dynamic assessment is not available, the fatigue test may not discover structural responses associated with this damage. If a structural fatigue test does not include quantitative assessments and simulated damage that is of probable sizes and at critical locations as determined from a dynamic load assessment, the resulting airworthiness limitations may not be adequate to prevent failures or excessive structural deformations.

The Van Horn composite blades are certificated on the basis of the “no-growth” method. This method is used to show that “the structure, with damage present, is able to withstand repeated loads of variable magnitude without detectable damage growth within a specified replacement time.”^{Footnote 1} However, Van Horn’s quality assurance process has no established inspection for internal defects following production, or criteria for the permissible size of internal defects. Therefore, it is possible that an unknown intrinsic flaw could exist following production that might exceed a predefined damage limit and would affect the structural integrity of the helicopter blades. If helicopter main rotor blade manufacturing processes do not include internal inspections for defects or criteria for permissible defects, there is a risk that defects that affect structural integrity will not be identified.

Finally, the investigation examined Transport Canada’s (TC’s) approach to managing cardiovascular health and hypertension in pilots. Using a variety of different risk calculators and all available medical information about the occurrence pilot, an independent cardiology review was conducted as part of this investigation and determined that the pilot’s actual annual risk for a sudden incapacitating cardiovascular event exceeded 5% per year. This surpasses the 2% threshold set by TC and the 1% threshold cardiologists recommend for single-pilot operations. Post-mortem results confirmed the presence of extensive atherosclerotic coronary artery disease in all 4 major coronary arteries, with significant (>75%) stenosis. This analysis revealed that the pilot possessed many of the key indicators for a high-risk cardiac event. In this occurrence, TC’s civil aviation medical examination to assess pilot fitness did not identify the level of risk presented by the pilot. If TC guidance material and the civil aviation medical examination report do not require a Civil Aviation Medical Examiner (CAME) to perform a global cardiovascular assessment, when appropriate, there is an increased risk that a pilot with high cardiovascular risk factors will be incapacitated while operating an aircraft as a result of a medical event.

The investigation determined that the pilot was not forthcoming with his CAMEs about conditions that were being followed by his family physician. In addition, the pilot’s family physician did not report the pilot’s conditions to TC, which contributed to TC’s incomplete understanding of the pilot’s health. If pilots do not declare all health issues to TC CAMEs and/or if pilots’ family physicians do not report medical conditions that are likely to constitute an aviation hazard, as required, TC may not be able to accurately assess the medical fitness of pilots, resulting in an increased risk that pilots will operate with diagnosed medical conditions that could affect flight safety.

Media materials

News release

Deployment notice