Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
On 25 August 2021 at 1115 local time, a pilot and engineer were conducting an engine ground run of a Bombardier Challenger 600 aircraft on the apron at Essendon Airport, Victoria. The aircraft was privately owned/operated and had not conducted any flights since 2017.
The nosewheel was chocked, with the left seat foot brakes applied instead of the required parking brake due to previous issues with releasing the park brake. The Challenger’s two turbofan engines were successfully started with normal system indications, and the power levers moved to the low idle position. The power levers were then moved to the high idle position for a short time and then back to low idle, after which the aircraft moved forward and rolled over the chocks.
The pilot was applying pressure onto the left seat foot brakes, and tried pumping them, but the aircraft continued to move forward. The pilot then tried using the rudder pedals to steer toward a grass area off the apron without success. The Challenger hit a parked helicopter and another parked aircraft before rolling through a perimeter fence and colliding with a building (Figure 1), bringing the Challenger to rest about 30 seconds after it started to roll.
Source: Google Earth, annotated by the ATSB
The pilot shut down the left engine by moving its power lever to the idle cut-off position. The right engine power lever could not be moved into the cut-off position, so the pilot activated the right engine’s fire extinguishing system, which successfully shut down the engine. The pilot and engineer then exited the aircraft.
The aircraft received substantial damage to the nose, wing leading edge, and winglets. Post‑accident testing of the Challenger’s brake system could not be performed due to hydraulic system damage from the accident.
The pilot and engineer are considering the use of additional chocks during aircraft ground running.
It is important to follow all operational procedures during engine ground runs, especially those related to securing the aircraft from moving. Positioning the aircraft away from obstacles during the ground run, for example at an airport’s run-up area, can also reduce the risk of colliding with obstacles should the aircraft unexpectedly roll. If this occurs, flight and maintenance crew must be prepared to initiate emergency actions, such as engaging brake systems and immediately shutting down engines.
After an extended period of inactivity, it is important to conduct full system checks before operating an aircraft.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
|Date:||25 August 2021||Investigation status:||Completed|
|Release Date:||06 October 2021||Occurrence category:||Accident|
|Report status:||Final||Highest injury level:||None|
|Aircraft manufacturer||Bombardier Inc|
|Aircraft model||Challenger 600|
|Type of operation||Private|
|Damage to aircraft||Substantial|