B737 / B737, vicinity Geneva Switzerland, 2006
B737 / B737, vicinity Geneva Switzerland, 2006
On 11 May 2006, B737-700 taking off from Geneva came into close proximity with a Boeing Business Jet (BBJ) on a non revenue positioning flight which had commenced a go around from the same runway following an unstabilised approach. The Investigation attributed the conflict to the decision of ATC to give take off clearance to the departing aircraft when the approach of the inbound aircraft could have been seen as highly likely to result is a go around which would lead to proximity with the slower departing aircraft.
On 11 May 2006, a B737-700 (G-EZJS)being operated by Easyjet on a scheduled passenger flight from Geneva to Luton under R/T call sign EZY 9VM came into close proximity in day VMC with another Boeing 737-700 configured as a Boeing Business Jet(BBJ) being operated on a non revenue positioning flight from Kasos, Greece to Geneva under call sign PTI 747 after it had taken off from runway 05. The BBJ had commenced a go around from an approach to the same runway following an unstabilised approach. The higher speed of the BBJ was such that it rapidly caught up with the departing 737. De-confliction instructions were given and separation increased from a minimum of 0.9 nm horizontally and 100 feet vertically.
The event was investigated by the Swiss Air Accident Investigation Bureau. Radar recordings were used as the primary source of data. Close proximity of both aircraft to the ground was found to have inhibited generation of Airborne Collision Avoidance System (ACAS) RAs but it was established that both aircraft had received a TA. The conflict was noted to have occurred between two IFR aircraft in Class 'D' airspace.
It was noted that the runway 05 ILS had been out of service with the ATIS offering a VOR/DME approach. The inbound BBJ had accepted a visual approach when aircraft was just over 20 nm from the runway at FL 155 and descending at approximately 270 KIAS, at which point manual control of the aircraft had been taken. By the time the APP controller asked the aircraft to reduce speed to 200 KIAS, it was at approximately 300 KIAS which then increased to over 320 KIAS when 5nm from touchdown. This high speed was not only contrary to the ATC instruction given but also well above the maximum permitted speed below FL100 of 250 KIAS. At 5nm from touchdown, the aircraft was almost 2000 feet higher than a 3° glideslope would require but the go around decision was not taken until it was just 1.5 nm from touchdown and at approximately 250 KIAS. The BBJ crew stated that they had "constantly maintained" visual contact with the departing 737.
The Investigation concluded that "from the time the pilot accepted a visual approach, he lost situational awareness as well as the overall control of (the visual approach)" and considered that it was "surprising that, faced with the evidence of an unstabilised approach, the pilot not flying did not intervene with his colleague at an opportune moment".
It was found that the inbound BBJ had declared and commenced a go around one minute after the 737 had been given take off clearance. This had occurred within less than a minute of two way contact between TWR and the BBJ being established.
"A succession of failings" by ATC was considered to have "led to a dangerous convergence of the two aircraft involved":
- TWR (being operated by a trainee and an OJTI) "could have noted on their radar monitor" that the high speed of the inbound aircraft "compromised the alignment and take-off" of the departing 737
- Although aware of the high speed and attempted steep descent of the inbound BBJ, the APP controller "had not judged it necessary" to inform the TWR controller of this when transferring the aircraft to TWR
- Recognising the potential for conflict when the BBJ declared a go around, TWR " tried, unsuccessfully, to resolve the problem by requesting the (BBJ) to reduce its speed immediately and by requesting the (departing 737) to begin its take off without delay because of landing traffic at 4nm.
- Avoiding action given by TWR to the 737 to "turn left onto heading 010° and
to continue climbing at a reduced rate" to its cleared level, FL 090, "did not specify that it was to do this in the form of a visual climb despite the configuration of the terrain towards which the aircraft was heading".
- Avoiding action give by TWR to the BBJ on go around "to climb at a high rate" did not remove the restriction of 4000 feet which was part of the missed approach procedure being followed despite the fact that "there was no VFR transit traffic above the CTR" (and so) an altitude of 7000 ft could therefore have been assigned to it directly, in coordination with Approach Control".
The Investigation "noted that the go-around procedure as designed compromises flight safety in the case of a simultaneous take-off by an aircraft from runway 05".
The Cause of the Serious Incident was formally determined as "the fact that ATC cleared an aircraft to line up and then to take off whilst an aircraft on final approach was making an unstabilised visual approach, the outcome of which would clearly be a go-around.
It was also noted that Contributory Factors had been:
- a lack of cooperation within the flight crew of the (Privat Air) aircraft
- a lack of cooperation between ATC APP and TWR
- inadequate avoiding action issued by ATC
The Final Report of the Investigation was completed on 26 February 2008. No Safety Recommendations were made.