Description

On 19 November 2017, an ATR 72-600 (VH-FVZ) being operated by Virgin Australia Airlines on a scheduled domestic passenger flight from Sydney to Canberra as VA646 made a hard touchdown at destination on the main landing gear and rear fuselage after a day VMC approach. The aircraft was able to be taxied in for normal passenger disembarkation but was then confirmed to have sustained substantial structural damage. No occupants were injured. The flight was a Line Check flight for both operating crew members being conducted from the supernumerary crew seat.

Investigation

An Investigation into the accident was carried out by the Australian Transport Safety Bureau (ATSB). Data from the aircraft FDR and CVR were downloaded and provided useful information.

It was noted that the Captain, who was a current Training Captain with the operator who had previously undertaken some of the operational training of the First Officer and had been designated as PF for the flight, had over 8,160 hours flying experience of which over 1900 hours were on type. The First Officer had over 1,320 hours flying experience of which over 320 hours were on type, accumulated over the preceding 6 months after he had obtained his type rating.

The accident flight was the final one of a four sector duty which was rostered as a routine annual Line Check on the Captain and a six-month Line Check on the First Officer to be carried out by a Check Captain occupying the flight deck supernumerary crew seat.

Prior to commencing descent, the First Officer briefed the approach and landing for runway 35 at Canberra noting that, based on the ELW of 21.6 tonnes, the VAPP would be 113 KIAS and also noting that the north easterly surface wind there would mean that a 15 knot crosswind component could be expected. He also stated 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”.

A visual approach to runway 35 was subsequently commenced “in conditions of light turbulence” with the AP engaged and was initially stable. Passing approximately 400 feet aal, the First Officer disconnected the AP and continued the approach manually. As the aircraft descended through 265 feet, the aircraft speed reduced and the PF increased power to compensate but as descent continued through 193 feet agl, the prevailing light turbulence “combined with the increased power setting to increase the speed further” and after eight seconds, with the aircraft 118 feet agl, it had reached VAPP + 14. The First Officer “did not recognise” the fact that the criteria for a stable approach were no longer satisfied but, having assessed the presence of an increased headwind component, he had responded by reducing engine power from 26% torque to idle, an action which itself was contrary to the operator’s stabilised approach criteria. As a result of this power reduction, the rate of descent increased and the airspeed decreased. At about the same time, the Check Captain reported having “recognised that the power setting was too low but assessed that input from him would not assist in the recovery of the approach”.

With just five seconds to go before the touchdown, the Captain reported realising that the First Officer’s idle power setting was too low and had advised him to “ease on a bit” (of power). The First Officer verbally acknowledged the advice but did not follow it and at 50 feet agl the aircraft rate of descent had increased to 784 fpm, over 200 fpm more than the ‘normal’ rate of descent. Then, at a recorded height of 27 feet above the runway and two seconds prior to touch down, it was apparent that the aircraft had encountered a wind shift which further increased the descent rate. Both operating pilots stated that they had “felt a sudden increase in descent rate at that point” and in response, the Captain “immediately called more urgently for an increase in power and manually intervened by advancing the power levers slightly” (by a recorded 3%). Two seconds later, anticipating a bounced landing, the Captain instructed the First Officer to commence a go-around but “almost immediately” the aircraft, by now descending at 928 fpm, touched down at a recorded 2.97g on the main landing gear, the tail skid and the underside of the rear fuselage. The aircraft did not bounce and so the Captain “cancelled the go-around, took control and completed the landing roll” following which he taxied the aircraft to the allocated gate.

The damage sustained to the fuselage during the landing was subsequently found to be limited to impact and abrasion damage to the tail skid and the underside of the rear fuselage forward of it, with re-skinning of sections of the lower fuselage and replacement of the tail skid and a drain mast required before the aircraft could be returned to service.

After completion of the flight, the Check Captain assessed the First Officer’s Line Check as a fail and the Captain’s Line Check as a Pass but “the operator required both flight crew to undergo retraining prior to resuming normal flying duties”. During a subsequent interview, the Check Captain stated that “he would have intervened in the conduct of the flight if he felt that the safety of the flight was compromised (but) after recognising that the approach had become unstable” he had “assessed that the landing would be ‘untidy’, but not unsafe” noting that “at that stage, input from him was outside of his role, might distract the flight crew and would not assist in the recovery of the approach”.

The Captain being line checked subsequently stated that during Check Flights, “he had a tendency to modify his behaviours and allow First Officers more margin than normal when correcting deviations in the operation of the aircraft […] in order to allow them an opportunity to rectify any deviations (whereas) during normal operations, he would intervene more quickly after identifying a deviation”.

Noting that the already excessive rate of descent after the almost complete absence of power below a recorded 118 feet agl had been increased by the effect of changes in wind velocity, the computed wind in the final 5 seconds of the flight were examined and it was found that the 10-12 knot headwind component between 5 and 3 seconds prior to touchdown had then rapidly reduced to zero and then become a 2 knot tailwind component.

The Conclusion of the Investigation was that “The continuation of the approach when a go-around should have been conducted allowed the subsequent conditions to develop, leading to the hard landing”.

Four Contributing Factors were identified as:

• 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 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.

Safety Action known to have been taken by Virgin Australia Airlines in respect of ATR 72 flight operations as a result of the investigated event was noted to have included:

• amending operational documentation to strengthen guidance on the effects of sustained low power settings during approach and landing and the importance of avoiding that situation.
• reinforcing existing pilot training on speed management during approach and landing.
• adding additional criteria to its OFDM programme to detect low power settings at low heights during normal operations.

On the basis of the findings of the Investigation, the ATSB formally documented a Safety Message as follows:

Unstable approaches continue to be a leading contributor to approach and landing accidents and runway excursions. This occurrence demonstrates the importance of crews adhering to standard operating procedures and conducting a go-around when an approach becomes unstable. It also highlights the risks associated with the incorrect handling of an approach to land and the need for prompt and decisive action as the available time to remedy the situation is limited.

The Final Report was released on 12 November 2019. No Safety Recommendations were made.

Related Articles

• Stabilised Approach
• Energy Management during Approach
• Missed Approach
• Go Around
• Pilot Flying (PF) and Pilot Monitoring (PM)