Near Mid-Air Collision at Évora Aerodrome Due to Non-Standard Circuit Entry

Casualties unknown • Évora, PT

A Socata TB20 and a PAC 750XL narrowly avoided a collision at Évora Aerodrome when the latter entered the landing circuit using an atypical flight profile.

What happened

On December 16, 2009, at approximately 12:40 UTC, a Socata TB20, registration CS-DES, was conducting a flight training mission at Évora Aerodrome. The aircraft, carrying an instructor and a student pilot, was positioned on the left downwind leg of runway 19. At this time, the Aerodrome Flight Information Service (AFIS) had notified the crew of other traffic in the vicinity flying at a similar altitude.

Simultably, a PAC 750XL, registration D-FGOJ, was performing a training flight related to skydiving operations. Following local custom for parachute jumps, the pilot of D-FGOJ descended to the west of the aerodrome to enter the right base leg of runway 19, a path contrary to the standard circuit flow. During this maneuver, the D-FGOJ unexpectedly appeared in close proximity to the CS-DES. The two aircraft passed within approximately three meters of each other, forcing the crew of the CS-DES to perform an emergency evasive maneuver to avoid a fatal impact.

The investigation

The GPIAAF investigation examined the flight paths and communication logs at Évora Aerodrome. The pilot of the D-FGOJ stated that they entered the circuit without confirming the presence of other aircraft and claimed that they were unable to contact AFIS because the frequency was continuously occupied. The investigation also reviewed the local agreements regarding skydiving operations, which dictate specific entry procedures for aircraft performing jump-related tasks.

Findings

  • The pilot of the D-FGOJ failed to follow standard circuit entry procedures, opting for an atypical and non-standard path while heavy traffic was present.
  • While the pilot cited a saturated AFIS frequency as a barrier to communication, the investigation determined that frequency congestion does not excuse the failure to maintain proper separation or follow established procedures.
  • The crew of the D-FGOJ did not adhere to standard traffic patterns, which would have been required if they were not actively engaged in a live parachute deployment mission.
  • The near mid-air collision was primarily caused by the failure of the D-FGOJ crew to observe local circuit entry procedures.
  • The collision was averted solely due to the rapid and effective evasive action taken by the pilots of the CS-DES.

Probable cause

The near mid-air collision was caused by the crew of the PAC 750XL (D-FGOJ) entering the landing circuit using a non-standard flight profile and failing to follow local procedures for traffic integration, combined with a lack of effective communication due to a saturated AFIS frequency.

Frequently asked questions

What happened in the 2009-12-17 Socata TB-20  ;  PAC 750XL accident near Évora, PT?

A Socata TB20 and a PAC 750XL narrowly avoided a collision at Évora Aerodrome when the latter entered the landing circuit using an atypical flight profile.

What aircraft was involved and where did it happen?

The accident on 2009-12-17 involved a Socata TB-20  ;  PAC 750XL, registration CS-DES, at Évora, PT.

What was the probable cause of the accident?

The near mid-air collision was caused by the crew of the PAC 750XL (D-FGOJ) entering the landing circuit using a non-standard flight profile and failing to follow local procedures for traffic integration, combined with a lack of effective communication due to a saturated AFIS frequency.

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