Near Collision Between Two Training Aircraft at Grenoble Isère Aerodrome (F-GGNM)

Incident Overview On Wednesday, July 25, 2012, at 12:10 local time, a near collision occurred in the traffic pattern at Grenoble Isère aerodrome (38) involving two aircraft operated by a flight school: a Socata TB10 Tobago registered F-GGNM and a Socata TB20 Trinidad registered F-GGNQ. No injuries or damage were reported. ## Circumstances The crew of the TB10 (F-GGNM), consisting of a student and an instructor, was cleared to join the final approach for runway 09 after a local flight. The air traffic controller informed them they were behind a Piper PA28 on an IFR final approach. The TB10 instructor stated the student was maintaining level flight at 1,800 feet until joining the final approach. The controller issued a traffic information in English to the crew of the TB20 (F-GGNQ), which was at the end of the downwind leg, instructing them to join the final approach behind the TB10. The TB20 instructor reported seeing traffic in the direction indicated and adjusted their pattern to position behind it. Based on radio communications, the instructor believed they were second in sequence behind the TB10 and ahead of another IFR aircraft 4 nautical miles out. However, the aircraft identified by the TB20 instructor was actually the PA28 in short final ahead of the TB10. The TB10 instructor observed the TB20 passing slightly above and to the right at a slightly higher speed, estimating the separation at approximately 10 meters. The TB10 crew reported the near collision to the controller. On the controller's request, the TB20 crew went around, while the TB10 continued its approach and landed normally. ## Weather and Personnel Weather conditions were: variable wind at 3 knots, visibility greater than 10 km, and few clouds at 5,000 feet. The TB10 instructor had 5,990 total flight hours, including 1,800 on type and 136 hours in the preceding three months (52 on type). The TB10 student had 20 hours, all on type. The TB20 instructor had 763 total hours, including 276 on type and 11 hours in the preceding three months (33 on type). The TB20 student had 110 hours, including 10 on type, and was a foreign student in integrated training. Radio communications with the TB10 crew were conducted in French, while those with the TB20 crew were in English. ## Contributing Factors The controller was assisted by a second controller handling telephone coordination and traffic supervision. The controller noted that traffic was dense but believed the most difficult phase was over as aircraft were well sequenced. The controller's strategy was to have VFR aircraft visually acquire the preceding aircraft to follow. The controller did not provide a sequence number, considering it unnecessary due to high traffic volume. However, French aviation regulations (RCA Chapter 5, paragraph 5.3.1.2) specify that sequence numbers should normally be communicated on the downwind leg and no later than the end of the downwind leg. The frequency was heavily occupied with diverse traffic, including IFR and VFR training flights.