Aircraft Accident Report 6/2010 - Grob 115E Tutors, G-BYUT and G-BYVN, 11 February 2009

Formal Report AAR 6/2010. Report on the accident to Grob 115E Tutor, G-BYUT and Grob 115E Tutor, G-BYVN near Porthcawl, South Wales on 11 February 2009.


The accident was reported to the Air Accidents Investigation Branch (AAIB) on 11 February 2009 at 1107 hrs. A field investigation was commenced immediately. A Royal Air Force (RAF) Service Inquiry was also convened, which conducted a parallel investigation. The following inspectors participated in the AAIB investigation:

Mr P Taylor Investigator in Charge
Mr K W Fairbank Operations
Mr A Cope Engineering
Mr S Moss Engineering
Mr P Wivell Flight Data Recorders

The two aircraft involved in the accident were based at MOD St Athan near Cardiff and were engaged on air experience flights when they collided in midair. The aircraft were piloted by RAF pilots and each aircraft carried an air cadet as a passenger. The collision occurred in uncontrolled airspace in fine weather, in an area which was routinely used by St Athan based Tutor aircraft.

The investigation identified the following causal factor:

  1. Neither pilot saw the other aircraft in time to take effective avoiding action, if at all.

The investigation identified the following contributory factors:

  1. The nature of the airspace and topography of the region reduced the available operating area such that the aircraft were required to operate in the same, relatively small block of airspace.

  2. There were no formal procedures in place to deconflict the flights, either before or during flight.

  3. The small size of the Tutor and its lack of conspicuity combined to make visual acquisition difficult in the prevailing conditions.

  4. At various stages leading up to the collision, each aircraft was likely to have been obscured from the view of the pilot of the other aircraft by his aircraft’s canopy structure.

Fifteen Safety Recommendations were made by the RAF Service Inquiry (SI) panel. No further recommendations have been made in this report.

Download full report:

6-2010 G-BYUT G-BYVN.pdf (1,492.13 kb)

Download bulletin summary:

Summary: AAR 6/2010 - G-BYUT and G-BYVN

Published 10 December 2014