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Loss of Separation Between Airbus A310 and Boeing 767 in Lisbon FIR (CS-TKI)

FIR Lisboa, PT

On September 13, 2005, an Airbus 310 ; Boeing 767 (registration CS-TKI) was involved in an aviation accident near FIR Lisboa, PT. Investigators recorded the probable cause as: The cause of the incident was the failure to update the flight plan of flight YSS818 in the OLDI system of ACC Lisbon, despite the route change authorization having been issued by ACC Santa Maria, which led to a loss of separation between the two aircraft. This summary draws on records from the Portuguese Office for the Prevention and Investigation of Accidents in Civil Aviation and Rail (GPIAAF).

Sourcesthe Portuguese Office for the Prevention and Investigation of Accidents in Civil Aviation and Rail (GPIAAF)Primary reportUpdated 2026-10-18Data APIEditorial standards
Aircraft registered CS-TKI
Aircraft registered CS-TKI. Photo: Luc Verkuringen / CC BY 3.0, via Wikimedia Commons

On 13 September 2005, an Airbus A310 (YSS818) and a Boeing 767 (AAL69) experienced a loss of separation near KOMUT in Lisbon FIR due to a failure to update the flight plan in the OLDI system. The TCAS RA was not followed as horizontal separation was ensured.

Factual Information

On 13 September 2005, at approximately 11:00 UTC, an Airbus A310 with registration CS-TKI and call sign YSS818, operating a flight from Cancun to Lisbon, and a Boeing 767 with call sign AAL69, operating from Madrid to Miami, were on reciprocal tracks at flight level 360 in the West Sector of Lisbon ACC (class C airspace). The aircraft came within less than the required separation, triggering a TCAS Resolution Advisory (RA) for the A310. The crews had visual contact and the AAL69 executed a right turn to increase lateral separation, while neither crew followed the TCAS RA as horizontal separation was already ensured. Visibility was greater than 10 km.

Coordination and Communication

Earlier, YSS818 had requested a route change to enter Lisbon FIR at KOMUT instead of the filed entry point GUNTI. Santa Maria ACC authorized the change and sent an Advanced Boundary Information (ABI) message via the OLDI system to Lisbon. However, due to a mismatch between the new entry point (KOMUT) and the original flight plan (GUNTI), the ABI message was rejected and printed on the "rejected printer" at the Flight Data Service (SDV) in Lisbon ACC. According to the operator and supervisor, they were verbally instructed by the TICA Advisor to ignore all such messages because the system was under testing. The TICA Advisor refuted giving such instructions. No written instructions were found overriding the relevant service instruction (IS062/05/CONLIS).

As a result, the flight plan for YSS818 was not updated in Lisbon's OLDI system. When Santa Maria sent the activation (ACT) message, no logical acknowledgment (LAM) was received, prompting Santa Maria to coordinate manually by telephone. At 10:34, Santa Maria telephonically coordinated YSS818 with Lisbon's West Sector. Meanwhile, AAL69 entered the sector and was later cleared to climb to FL360 via KOMUT. At 10:59, the two aircraft crossed within close proximity, resulting in the TCAS RA.

Analysis

The incident was caused by the failure to update the flight plan of YSS818 in Lisbon's OLDI system, despite the route change authorization from Santa Maria. This led to a loss of separation between the two aircraft. The verbal instruction to ignore rejected ABI messages, if indeed given, contradicted the established service instruction. Additionally, there was no clearly defined boundary for reverting from radar to conventional control in the area where radar coverage was not guaranteed.

Conclusions

3.1 Facts Established

  • The incident occurred on 13 September 2005 at approximately 11:00 UTC.
  • Aircraft involved: Airbus A310 (CS-TKI, YSS818) and Boeing 767 (AAL69).
  • Both aircraft were at FL360 on reciprocal tracks.
  • A TCAS RA was generated but not followed; lateral separation was ensured by an AAL69 turn.
  • No injuries, fatalities, or damage to aircraft.
  • Communications were functional, though VHF frequency 128.9 MHz was noisy.
  • The flight plan of YSS818 was not updated in Lisbon's OLDI system.
  • Santa Maria and Lisbon coordinated manually after the automatic coordination failed.

3.2 Cause of the Incident

The cause of the incident was the failure to update the flight plan of flight YSS818 in the OLDI system of ACC Lisbon, despite the route change authorization having been issued by ACC Santa Maria, which led to a loss of separation between the two aircraft.

Recommendations

The report lists recommendations (not reproduced here) aimed at preventing recurrence.

Probable cause

The cause of the incident was the failure to update the flight plan of flight YSS818 in the OLDI system of ACC Lisbon, despite the route change authorization having been issued by ACC Santa Maria, which led to a loss of separation between the two aircraft.

Frequently asked questions

What happened in the 13 Sept 2005 Airbus 310 ; Boeing 767 accident near FIR Lisboa, PT?

On 13 September 2005, an Airbus A310 (YSS818) and a Boeing 767 (AAL69) experienced a loss of separation near KOMUT in Lisbon FIR due to a failure to update the flight plan in the OLDI system. The TCAS RA was not followed as horizontal separation was ensured.

What aircraft was involved and where did it happen?

The accident on 13 Sept 2005 involved an Airbus 310 ; Boeing 767, registration CS-TKI, at FIR Lisboa, PT.

What was the probable cause of the accident?

The cause of the incident was the failure to update the flight plan of flight YSS818 in the OLDI system of ACC Lisbon, despite the route change authorization having been issued by ACC Santa Maria, which led to a loss of separation between the two aircraft.

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