Incident Overview

Description
Boeing 717 VH-NXE, was being operated on a scheduled passenger service from Cairns, via Gove-Nhulunbuy (GOV) to Darwin (DRW). The copilot was the handling pilot for the descent, approach and landing at Darwin and the pilot in command was the monitoring pilot. The crew had received a weather briefing prior to the departure from Cairns, informing them that there were showers and thunderstorms in the Darwin area for their arrival. Air traffic control (ATC) cleared the crew to conduct the Darwin runway 29 ILS approach. The monitoring pilot stated that the runway was in sight prior to flying over the Howard Springs non-directional beacon (NDB). Information from the aircrafts flight data recorder (FDR) indicated that the aircraft flew over the Howard Springs NDB at about 3,000 ft above mean sea level (AMSL), with a computed air speed of 221 knots. The aircraft was configured for landing at the outer marker, where the handling pilot disconnected the autopilot and the approach was flown manually by reference to the ILS and visual reference with the runway lighting. During the approach and landing, the aircraft autothrottle remained engaged. At approximately 700 ft AMSL, the aircraft entered a rain shower. The monitoring pilot switched on the windscreen wipers and, as both pilots stated that they could see the runway lighting and PAPI, the approach was continued. At approximately 30 ft radio altitude, the FDR recorded a rate of descent of approximately 1,000 ft/min at the same time as an abrupt control column nose up command was applied. The copilot recalled hearing the synthesised calls of radio altitude from the aircrafts radar altimeter. At 21:14:50, the aircraft touched down with a rate of descent of about 1,000 ft/min, which resulted in a hard impact with the runway prior to the 300 m runway markings. The aircraft then bounced before settling onto the runway. The crew completed the landing rollout and taxied the aircraft to the terminal. CONTRIBUTING SAFETY FACTORS: – The aircraft was above the glideslope at the Howard Springs non-directional beacon and throughout the majority of the approach, resulting in high rates of descent on several occasions as attempts were made to capture the glideslope. – The copilot disconnected the autopilot at a time of high workload. – The aircraft’s rate of descent below 400 ft above aerodrome level exceeded the operators stabilised approach criteria; however, because the pilot in command considered the exceedance to be momentary, a missed approach was not conducted. – The allowance of momentary excursions in the aircraft operators stabilised approach criteria that were caused by wind gusts or turbulence increased risk by permitting flight crew discretion to continue approaches at or beyond those criteria. [Minor safety issue] – The operators procedure for the use of the autothrottle in response to high rates of descent when below 30 ft during landing was not included in the operators standard operating procedures. [Minor safety issue] – At about 30 ft, the copilot made an abrupt rearward movement of the control column resulting in the main landing gear moving faster downwards than the aircrafts overall rate of descent. OTHER SAFETY FACTORS: – The operators process for reporting 717 pilot training issues to senior managers was not utilised by all flight crew, reducing the potential for the communication of fleet-wide issues to all 717 crews. [Minor safety issue] – There was no clear division of responsibilities between the aircraft operator and the third party training provider in regard to ensuring the standards of flight training met all of the operators requirements, which had the potential to reduce training effectiveness. [Minor safety issue] – There was no provision in the current Civil Aviation Safety Authority regulations or orders regarding third party flight crew training providers, with the effect that the responsibility for training outcomes was unclear. [Minor safety issue] – There was no aircraft operators or manufacturers 717 pilot training manual that provided for the standardisation of instructional technique and provided a reference document for pilots during and following training. [Minor safety issue] – The control column moved forward after touchdown, resulting in excessive weight transfer to the nosewheel before the right mainwheel was correctly loaded. – After touchdown, the thrust levers were advanced, inadvertently cancelling the deployment of the ground spoilers and resulting in unstable conditions while transitioning from flight to the ground. – The aircraft operator’s Route Manual did not include all relevant information on the potential for visual illusions during a night approach to runway 29 at Darwin Airport that would have improved the awareness of flight crews. [Minor safety issue] – The Jeppesen-Sanderson Inc. approach chart titled Darwin, NT Australia ILS-Z or LOC-Z Rwy 29 dated 21 SEP 07 incorrectly depicted a level flight segment after the Howard Springs non-directional beacon that could have been misinterpreted by flight crews. [Minor safety issue] – The lack of runway centreline lighting reduced the available visual cues during the latter stages of the approach and landing to runway 29 at Darwin Airport.
Primary Cause
The incident was likely caused by a combination of factors, with the most significant contributing factor being the pilot in command’s decision to continue the approach despite the descent rate exceeding the operator’s stabilised approach criteria, potentially due to workload and a momentary excursion in the aircraft’s autothrottol. The pilot’s actions to engage the autothrottol at a time of high workload and the subsequent rapid control column movement contributed to the incident.The incident was likely caused by a combination of factors, with the most significant contributing factor being the pilot in command’s decision to continue the approach despite the descent rate exceeding the operator’s stabilised approach criteria, potentially due to workload and a momentary excursion in the aircraft’s autothrottol. The pilot’s actions to engage the autothrottol at a time of high workload and the subsequent rapid control column movement contributed to the incident.Share on: