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19th of November 2017 Blog #574

With a crew of five and 57 passengers, an ATR 72-600 was operating a domestic scheduled flight between Sydney and Canberra. The standard cockpit crew of a captain and co-pilot was supplemented by a Check-captain on the jump seat in the fligthdeck. He was conducting a line check on both the captain and copilot during the flight.

The aircraft touching down hard (Source; ATSB, taken from airport CCTV) The ~250-kilometres (135 nautical miles) flight had proceeded without incident when the co-pilot (Pilot-Flying - PF) briefed the captain for the approach.

He advised that the calculated target approach speed was 113 kt, the expected landing weight was 21,600 kg and that the reported weather indicated a crosswind from the right of 15 kt for a landing on runway 35. He also advised the captain that due to the heavy aircraft weight and the possibility of a tailwind at times during the approach, he would slow the aircraft earlier than normal to ensure the approach commenced at the target speed.


After receiving their clearance for the approach to runway 35 at Canberra the crew was flying a visual approach in light turbulence with the autopilot engaged. At 400 ft altitude, the autopilot was disconnected and the approach continued being manually flown. A short while later at 265 feet altitude, still in light turbulence, the airspeed started to drop, in response, the PF increased power. At 193 feet, still in light turbulence, the speed continued to increase, reaching 127 knots, exceeding one of the criteria for a stabilised approach while descending through 118 feet. The PF recognised an increase in speed and reduced the engine power to idle. This was a second deviation from the stabilised approach criteria. As a result of the power reduction, the rate of descent increased. The check captain recognised that the power setting was too low, but assessed that input from him would not assist in the recovery of the approach.

The damaged lower fuselage and tail skid (Source; ATSB)


Five seconds prior to touchdown the PM advised to add a bit of power, the PF verbally responded, but did not increase power. 50 feet above the runway the vertical speed was 784 feet/minute (normal 575 ft/min). Two seconds prior to touchdown the aircraft encountered a wind shift that increased the descent rate. Both pilots recognised the increase and the PM intervened by increasing power. In anticipation of a bounced landing the PM called for a go-around, at the same time the aircraft touched down heavily on the main gear, tail skid and aft fuselage. The aircraft did not bounce and the PM cancelled the go-around, took control of the aircraft and completed the landing roll. The crew recognised a hard landing from the recorded data, mandating a maintenance inspection of the aircraft. None of the occupants sustained any injury, the aircraft was damaged substantially, Damage to the aircraft was observed at;

  • Tail skid (impact and abrasion damage)

  • The underside of rear fuselage forward of the tail-skid (impact and abrasion damage)

  • Drain mast

The aircraft underwent a re-skinning of the damaged areas before being returned to service.

The damaged tail skid from the accident aircraft with a worn limit stroke detector (left) and an undamaged tail skid (left) (source; ATSB)


An investigation into the accident was launched by the Australian Transport Safety Bureau (ATSB), in their report they identified the following contributing factors to the accident;

  • During the approach, the pilot flying did not identify that the speed had exceeded the stabilised approach criteria, which required immediate correction or initiation of a go-around.

  • In response to an assessment of overshoot shear, the pilot flying reduced power to idle at a height greater than that stipulated by operator procedures. This resulted in an abnormally high descent rate that was not reduced prior to the touchdown.

  • A significant change in the wind direction and strength immediately before the aircraft touched down further increased the aircraft's descent rate and contributed to the resultant damage.

  • Verbal and physical intervention by the pilot monitoring did not prevent the hard landing

FDR Data from the accident (Source; ATSB)


The ATSB report, which was used as the source for this blog, can be accessed by clicking on the file below;

ATR 72 hard landing 17-nov-2017
.pdf
Download PDF • 1.32MB

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