Steve Ayres summarises and comments on accident reports from around the world and suggests this would be a good time to read Engines, by Mike Busch.
17 February 2021
The aircraft departed from Runway 20 at White Ox Mead Airstrip in fine weather conditions. Towards the end of the take-off run the pilot reported feeling a distinct high-frequency vibration, but as he was beyond the point on the runway where the aircraft could safely be stopped, he continued with the take-off. The vibration continued as the aircraft became airborne so the pilot reduced power and started a left turn, with the intention of returning to the airstrip if the vibration continued. As the aircraft climbed through 250ft agl the vibration increased and the pilot reported hearing a loud bang and observed a propeller blade passing over the canopy. The vibration increased significantly after the propeller blade detached, causing the forward-hinged canopy to open and be sucked upwards into the airflow. The engine also stopped, which the pilot subsequently determined was due to the carburettors detaching from the inlet manifolds.
At approximately 200ft agl the pilot selected a crop field, which was into wind and had an upslope, and made a successful forced landing. No additional damage was incurred during the landing. Despite a search of the area that the aircraft had overflown, the detached propeller blade was not located.
The absence of any evidence of progressive cracking prior to the blade’s release indicates that the propeller was weakened prior to the failure, possibly due to contact with the ground or a foreign object. The increasing level of vibration experienced during the latter stages of the take-off roll is consistent with a change in the stiffness or mass of a propeller blade during the take-off roll.
Comment This could have ended very badly. Engine failure at low level leaves few options, but clear-headed actions and deft handling resulted in a good outcome. Losing a prop blade is worrisome, though, and it would be good to know what caused it.
The aircraft was being positioned via an overhead join for an approach to land on Runway 26 at Compton Abbas. When the landing gear was selected down there was a sudden smell of burning. The pilot, believing there was a fire or an imminent risk of fire, immediately made an emergency call to ATC and positioned the aircraft for a shortened approach. The aircraft touched down normally and rolled on its landing gear for around 80m before it collapsed and the aircraft slid along on its belly. Once the aircraft came to a halt, the occupants vacated the aircraft with the fire service in attendance. Initial enquiries suggested the landing gear failed to lock down due to a burnt-out electrical gear motor.
“When the landing gear was selected down there was a sudden smell of burning”
Comment To be back safely on terra firma after a suspected electrical fire cannot be a bad result, but landing with the undercarriage in an unsafe condition does come with its own risks.
Connecting the smell of burning with the movement of the undercarriage selector switch could have led to a prompt diagnosis of the cause and allowed time to reflect on how best to sort the problem of an unlocked undercarriage before committing to land. But, of course, hindsight can be a wonderful thing!
A Champion aircraft equipped with floats, departed Golden Lake, Ontario, for a VFR flight with just the pilot on board. As the aircraft approached Chat Falls on the Ottawa River, the pilot descended to 1,500ft and made a position call on the training area frequency while tracking 085°. A few minutes earlier a Cessna 172M aircraft departed Arnprior Airport with the pilot and three passengers on board, for a VFR flight to Constance Bay.
The pilot climbed to 1,500ft before switching to the training area frequency and broadcasting the aircraft’s position and his intentions for the flight. After making a few sightseeing orbits the aircraft flew a track of approximately 050°. Shortly after, the two aircraft collided while flying over the Ottawa River near Buckham’s Bay. The Champion sustained damage to the tail, entered a descending left-hand turn, struck the water, and overturned. The pilot egressed from the aircraft and was rescued by nearby boaters. The pilot received minor injuries. The Cessna sustained damage to the propeller, nosewheel fairing and engine cowl.
The pilot of the Cessna saw the Champion strike the water. He flew a few orbits to confirm that the pilot had been rescued, and transmitted a Mayday call before returning to land without further incident.
Comment This was a narrow collision angle of 35° and the aircraft would have been within mutual visual detection range for many seconds.
However, as with all collisions, the absence of any lateral movement would have made spotting the impending collision difficult without a good lookout scan. Neither aircraft had any form of electronic conspicuity device and the investigation identified systems such as FLARM and ADS-B as offering the potential to significantly reduce the risk of collision.
During an aerobatics training flight, the aircraft struck the ground while in a spin. The aircraft was destroyed and both pilots were fatally injured. A definitive cause could not be determined, but it is likely that the commander became incapacitated during a spin and the student was unable to recover the aircraft in time.
“It is likely that the commander became incapacitated during a spin”
The post mortem identified that the commander had significant narrowing of a cardiac artery which would have placed him at risk of sudden death due to cardiac dysrhythmia, a condition particularly rare in those under 40. The commander had shown no history of illness and it is unlikely the condition would have been revealed by an ECG unless a significant physiological burden was applied, such as occurs with an exercise ECG.
The aircraft had a Centre of Gravity (CofG) position that was out of limits aft, which would have reduced the capability of the aircraft to recover and extended the time to do so.
Unapproved devices, which adjusted the rudder pedal positions, were found on the rudder cables but were unlikely to have been a contributory factor. Due to the additional weight penalty neither occupant was wearing a parachute.
Comment Although the cause could not be identified with certainty, it appears the boarding weights used for the CofG calculations were under-recorded and the weight and balance schedule for the aircraft was not the most up-to-date. This would have contrived to make exiting the spin more lengthy and, coupled with the difficulties of establishing who was in control, meant there was insufficient height to recover from the manoeuvre. Pre-spin briefing of actions in the event of incapacitation of either occupant need to be thorough and detailed, particularly in a tandem aircraft. They also need considerable time to action in the air.
A man climbed over a fence, which was covered in barbed wire, at night to gain access to Perpignan-Rivesaltes Airport and boarded a PA 44 parked in front of the maintenance hangar at the Aéropyrénées flight school.
He started the two engines which did not require a key, taxied and took off from a taxiway at around 0220, flying at low level around Perpignan for almost an hour in turbulent weather conditions. At around 0317, a witness on the ground saw the aircraft flying level, initiating a turn, adopting a nose-up attitude then nose-down towards the ground and impacting with high energy. The man in command of the aeroplane was 20 years old and of Italian nationality.
According to his parents, he had no aviation experience and his computer did not contain aircraft pilot simulation software. The toxicological analysis did not reveal anything which might explain the accident.
Comment The French BEA rightly make no attempt to understand the reasons behind this accident, although recommend that security at the airfield be reviewed.
While the motive may not be obvious, it is surprising that anyone with little or no exposure to aviation could get airborne from an unlit taxiway for a one hour, low level night flight in a piston twin. Something many of us reading these columns would struggle to achieve and for those involved, must have been terrifying.
With so many engine related safety articles in these columns, this book by Mike Busch makes the perfect read for a wet winter’s day in lockdown.
When reviewed for FLYER, Ian Seager concluded: If you are learning to fly, already flying and renting, or if you own a piston-powered aeroplane you should buy and read this book. It’s packed with pretty much any of us really need, or want, to know about aircraft piston engines. You’ll learn about the various systems, about how to fly, monitor and maintain them and figure out what’s wrong with them. Better still it’s all presented in an accessible manner that often relates to Mike’s own flying which makes it more interesting, more digestible and simpler to absorb. Five hundred pages for less than half an hour’s worth of avgas for most of us.
