Lessons Learned: Flying Below Minimum Altitude, Last Light

The flight below minimum altitude and at last light involved Cessna Citation 510, VH-IEQ, 13 km west of Bankstown Airport, New South Wales.

The Citation jet’s descent, at last light and below lowest safe altitude, or minimum altitude, on approach into Bankstown highlights to pilots to consider how operating rules may change during flight, particularly around last light, an ATSB (Australian Transport Safety Bureau) investigation report details.

On November 16, 2022, the Cessna Citation Mustang with a single pilot and one passenger on board was conducting a charter flight from Young to Bankstown.

As the aircraft approached Bankstown to land under the instrument flight rules, about 10 minutes after last light, the pilot established contact with air traffic control (ATC) and requested a “visual’ approach.” ATC approved the pilot to fly directly toward final approach for runway 11 center.

“The pilot proceeded to follow the rules applicable to day operations, as there was still some ambient light available,” ATSB Director Transport Safety Kerri Hughes explained.

“However, as the operation was taking place after last light, this meant the pilot descended below the lowest safe altitude applicable, reducing the assurance for separation from terrain and ground‑based obstacles.”

Flight data showed the pilot descended to a height of 1,000 ft, about 800 ft below the lowest safe altitude for the area at that time.

ATC subsequently issued a terrain safety alert, and the pilot reported they were visual. An uneventful landing was then conducted.

The ATSB report notes the flight was the fourth of the day, and the pilot had submitted all flight plans at about 0448 local time, before commencing operations.

“This incident highlights the importance of planning, in particular around times when rules change, such as the transition from day to night,” Ms. Hughes said.

“In this case, both planned and actual times when the flight below lowest safe altitude, or minimum altitude, occurred were after last light.”

During the investigation, the pilot reported that flying a published instrument approach procedure, rather than declaring “visual” would have been a more suitable plan for this flight.

Read the final ATSB report: Flight below minimum altitude involving Cessna Citation 510, VH-IEQ, 13 km west of Bankstown Airport, New South Wales, 16 November 2022, publication date: 05/06/2024.