What happened
On 24 February 2022, a Eurocopter EC135P2 helicopter, registration PK-RJH, was preparing for a non-scheduled flight from Seletar Airport, Singapore, to Batam, Indonesia. During the departure process, a Ground Movement Controller on-the-job trainee (GMC OJT) instructed the pilot-in-command to taxi to Holding Point E4 for Runway 03.
While the instruction to hold at the point was given, the pilot proceeded to taxi the aircraft directly onto Runway 03. The error was identified when the Runway Controller contacted the pilot, informing them that no clearance to enter the runway had been granted. The pilot acknowledged the mistake and apologized. No other aircraft were on the runway or on approach at the time, and the helicopter was cleared for takeoff shortly after.
The investigation
Investigators focused on two primary areas: the accuracy of radio communications and the visibility of airfield lighting. The investigation examined the transcript of the taxi instructions, noting that the pilot failed to include the critical phrase "holding point" in his readback. Although the trainee controller attempted to verify the instruction multiple times, she mistakenly believed the pilot had confirmed the hold. Additionally, the OJT instructor present noted the improper readback but did not intervene to request a correction.
Furthermore, the investigation looked into why the aircraft entered the runway despite the presence of active red stop bar lights at the holding point. The pilot stated that his attention was likely diverted toward scanning the approach path for other traffic, which led to him overlooking the illuminated lights.
Findings
- The pilot did not provide a proper readback of the taxi clearance, specifically omitting the instruction to hold at the holding point.
- The trainee controller incorrectly believed the pilot had confirmed the hold after several communication attempts.
- The OJT instructor failed to instruct the trainee to seek a more complete readback despite noticing the error.
- The pilot failed to notice the active red stop bar lights at the holding point, likely due to a focus on monitoring approaching aircraft.
Safety action
Following the incident, the aircraft operator implemented several safety measures, including a special briefing procedure regarding red stop bar lights and updated radio telephony training for all pilots. The Air Navigation Service Provider conducted skills enhancement training for the controllers involved and provided refresher courses on radio telephony discipline and instructor training for all aerodrome and approach personnel.