Story ID: 004
Accidents: December 2021
By: David Jack Kenny
Caption: Preliminary and final accident reports, December 2021
Word Count: 1594
Preliminary Reports
Turbine Commander Lost in Apparent Spin

Rockwell International 690B, September 28, 2021, Hiles, Wisconsin – The three crew members were killed and the airplane destroyed after it departed controlled flight during an aerial imagery survey flight for the Wisconsin Department of Natural Resources.  The Part 91 flight to capture images of forest vegetation departed from the Rhinelander-Oneida County airport at about 8:50.  Preliminary ADS-B data showed that it climbed to 15,600 feet and reached a maximum groundspeed of 209 knots, which decayed to 93 knots over the course of about two minutes.  Three minutes after it levelled off, ATC heard a radio transmission of “Mayday, Mayday, Mayday … we’re in a spin.”  The flight was not under ATC control or receiving flight following at any time.

A witness who saw the airplane spinning “nose down at a high rate of speed” estimated its rotation at “30 to 60 rpm” but did not observe the impact.  A combined aerial and ground search found the wreckage in forested wetlands about 10 miles east of Eagle River, Wisconsin.  Debris was concentrated within a radius of about 25 yards, with most below the water’s surface but some fragments found in the trees.  Clear skies were reported at the time of the accident, with 10 miles visibility and southerly winds of four knots.

Billionaire Among Eight Fatalities in Milan Departure Crash

Pilatus PC-12/47E, October 3, 2021, San Donato, Italy – The Romanian-registered turboprop crashed into an empty office building minutes after taking off from the Milano-Linate Airport, killing all eight on board.  Press reports indicate that the flight was bound for the Olbia Airport on the island of Sardinia.  The casualties included 68-year–old Romanian billionaire Dan Petrescu, his wife, and their 30-year-old son.  It was not immediately clear who was on the controls.

The flight climbed to 5,300 feet before entering a rapid descent.  The Milan prosecutor told reporters that the takeoff proceeded normally “until a certain point, then an anomaly appeared on the radar screen and it plunged.”  Air traffic control did not report any distress calls.  Weather conditions including variable five-knot winds from the southeast and broken ceilings at 5,000 feet.

Four Killed in Centurion Turboprop Conversion

Cessna P210 turbine conversion, October 8, 2021, Atlanta, Georgia – The 1978-model airplane crashed immediately after takeoff from the Dekalb-Peachtree Airport, killing all four on board.  Airport surveillance footage showed that it lifted off from Runway 21 in a nose-high attitude after a ground run of about 1,000 feet and rolled left into an inverted attitude before crashing nose-first next to the runway.  A post-impact fire consumed the cabin and instrument panel and caused extensive damage to both wings and the tail.  Both actuator rods had separated from the elevator trim actuator and were free to rotate.  The position of the inboard rod corresponded to a position of 5° tab down, while the outboard was at 5° tab up.

The airplane had been modified under a supplemental type certificate (STC) that replaced its original turbocharged Continental piston engine with a Rolls-Royce 250-B17 F/2 turbine engine rated for 450 shaft horsepower.  A five-bladed MT composite propeller had been installed under a second STC.  When the work was completed on July 19, 2021, the engine had been run for 2.3 hours since overhaul. 
Interim Reports
Jump Plane Ditched in Wadden Sea

Cessna 208, July 26, 2021, Norderney Airport, Germany – The skydiving platform crashed into the water on approach to the Norderney Island Airfield, killing the 65-year-old commercial pilot.  The flight was expected to land at Norderney Airfield to pick up 12 parachutists who’d jumped over the island from 14,000 feet.  One minute after the drop, the pilot turned left to a southeasterly heading and began a descent in coordination with the radar controller, initially coming down at 4,000 feet per minute and 160 knots groundspeed.  After reaching the mainland he made about a 210-degree left turn back over the Wadden Sea to enter an extended left base for Norderney’s Runway 26, moderating the descent rate after reaching the water.  The last contact by military radar showed the airplane at an altitude of 232 feet and 150 knots groundspeed.

A witness in a boat near the point of impact described the Caravan hitting the water “in swift straight flight with consistent engine and propeller noises and a pitch angle of about 30°.”  It overturned immediately after impact in about 1.5 meters (five feet) of water over the mud flats.  The first rescue boat reached the scene 20 minutes later, but the pilot’s injuries were subsequently deemed unsurvivable.  Most of the wreckage was recovered over the next two days.

The accident occurred on his eighth flight of the day.  The previous seven dropped skydivers above Borkum Island, the point of departure of the accident flight, and averaged 17 minutes in duration.  The pilot took a 30-minute break after the fourth flight and a 16-minute rest before the accident flight. A logbook recovered from the wreckage listed 6,562 hours of flight experience that included 18,194 landings.  All but one of his flights since August 8, 2017 had been skydiving flights.
Final Reports
Nose Gear Failure Tracked to Missing Hardware

Raytheon Hawker 800XP, October 7, 2019, Fort Myers, Florida – Following an emergency landing due to the nose gear’s failure to either retract or extend again, the nut, washer, and cotter pin that should have secured the nose gear actuator drag stay were discovered to be missing.  The threads on the attaching pin were found to have been deformed.  The operator’s heavy check maintenance provider had overhauled all three legs of the landing gear in January 2019, nine months and 124 cycles before the accident.  No other repairs or inspections of the nose gear had been performed in the interim, and though the provider’s task job cards for the nose gear overhaul had been signed off by a quality assurance inspector, the NTSB concluded that the washer, nut, and pin were never installed.

The Part 135 flight departed from Naples Municipal Airport at 11:05 p.m. with a planned destination of the Kerrville, Texas Municipal Airport.  During the initial climb, the captain felt a vibration and “thud” from the nose and the nose gear’s red warning light illuminated.  The main gear appeared to have retracted normally.  The crew followed checklist procedures to extend the main gear without success, and chose to divert to the Southwest Florida International Airport in Fort Myers to take advantage of the dry 12,000-foot runway.  The nose gear remained in its well after touchdown, and the airplane skidded to a stop on the runway.  The two passengers and both pilots evacuated without injury through the main cabin doors.

Procedural Irregularities Lead to Hoist Cable Failure

Airbus Helicopters AS 350 B3, February 4, 2020, Bulga, New South Wales, Australia – Inconsistent stowage procedures and an incorrect tally of operating cycles caused the rescue helicopter’s hoist cable to fracture during a maintenance procedure intended to rebalance the tension of the cable’s strands.  No flight or ground crew members were injured when the weight bag and hook separated from the cable and fell to the ground.

The ATSB found that the New South Wales National Parks and Wildlife Service (ParkAir) crews did not consistently follow the manufacturer’s recommended procedures for tensioning the cable after deployment to minimize vibration and associated wear.  Its method of counting operational cycles also resulted in the cable having been operated well in excess of its recommended life limits, likely contributing to the wear.  In response, ParkAir implemented revised training procedures including the use of a gauge to measure cable compression after stowage, a more conservative method for counting duty cycles with a life limit of 500, and inspection requirements consistent with Civil Aviation Safety Authority (CASA) Airworthiness Directive AD/SUPP/10.

Communications Lapses End in Gear Collapse

Fairchild SA226-T, August 19, 2020, Gunnedah, New South Wales, Australia – The pilot’s failure to check NOTAMs combined with a recent change in CASA’s Manual of Standards (MOS) governing Australian airports to lead the solo pilot to attempt to take off while the airport was closed.  As the airplane accelerated on its takeoff roll, he saw “something on the runway surface in the distance,” but thought they were patches in the pavement.  After realizing they were excavations he attempted to avoid them but was unable to clear the left main gear, which collapsed after hitting two holes excavated in the pavement of Runway 29, resulting in a propeller strike and damage to the left wing.  He was not injured.

The pilot, who had landed there the previous afternoon, was unaware of the NOTAM closing the airport for paving work from 0700 to 1500 that had been filed the previous day.  The airport windsock had been marked with a white “X” visible from the air to advise arriving pilots of the closure, but this was not visible (or designed to be) from the ground.  He advised Brisbane Center of his intention to take off, but by the time the Brisbane controller had checked NOTAMs and recognized the closure, he’d left the frequency.

The week before the accident, on August 13, the MOS was revised to require a works safety officer on the site of airport construction projects, obviating the requirement to specifically mark each runway and taxiway that was out of service.  The new requirements had been communicated by e-mail to a former staff member who was no longer employed by the airport and was never seen by airport staff.  The e-mail did not return as undeliverable, leaving CASA unaware that it had never been received.