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B737 / F100, vicinity Geneva Switzerland, 2006

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Summary
On 29 December 2006, Geneva ATC saw the potential for runway 23 conflict between a departing 737 and an inbound F100 and instructed them to respectively reject take off and go around respectively. Although still at a relatively slow speed, the 737 continued its take off and subsequently lost separation in night IMC against the F100. The Investigation noted that take off clearance for the 737 had been delayed by a slow post-landing runway clearance by a business jet and that the 737 had not begun take off after clearance to do so until instructed to do so immediately.
Event Details
When December 2006
Actual or Potential
Event Type
Human Factors, Loss of Separation
Day/Night Night
Flight Conditions IMC
Flight Details
Aircraft BOEING 737-700
Operator EasyJet
Domicile United Kingdom
Type of Flight Public Transport (Passenger)
Origin Geneva Cointrin International Airport
Intended Destination London Luton Airport
Take off Commenced Yes
Flight Airborne Yes
Flight Completed Yes
Flight Phase Missed Approach
APR
Flight Details
Aircraft FOKKER F100
Operator KLM Cityhopper
Domicile Netherlands
Type of Flight Public Transport (Passenger)
Origin Amsterdam Airport Schiphol
Intended Destination Geneva Cointrin International Airport
Take off Commenced Yes
Flight Airborne Yes
Flight Completed Yes
Flight Phase Missed Approach
APR
Location - Airport
Airport vicinity Geneva Cointrin International Airport
General
Tag(s) Aircraft-aircraft near miss
HF
Tag(s) ATC clearance error,
Plan Continuation Bias
LOS
Tag(s) Required Separation not maintained,
ATC Error,
Near Miss,
Go Around Separation
Safety Net Mitigations
Malfunction of Relevant Safety Net No
TCAS Available but ineffective
Outcome
Damage or injury No
Causal Factor Group(s)
Group(s) Aircraft Operation,
Air Traffic Management
Safety Recommendation(s)
Group(s) None Made
Investigation Type
Type Independent

Description

On 29 December 2006, a B737-700 (G-EZJL) being operated by Easyjet on a scheduled passenger flight from Geneva to Luton as EZY 2076 cleared for take off did not reject its take off when requested to do so as ATC were also instructing a FOKKER F100, (PH-OFF) being operated by KLM CityHopper under call sign KLM 57W to make a non standard go around and the two aircraft subsequently lost separation with a minimum of 1nm horizontally and 300 feet vertically in night Instrument Meteorological Conditions (IMC).

Investigation

An Investigation was carried out by the Swiss Air Accident Investigation Bureau, primarily using radar recordings.

The instruction to the 737 to reject the take off was found to have been given 20 seconds after the pilot had confirmed that take-off was being commenced in response to a request from TWR for an immediate take off after the initial clearance had still not been actioned. Radar recordings showed that when the instruction was given, "the aircraft was approximately 400 m from the threshold of runway 23" and its ground speed was 74 knots. Given this relatively low speed, the Investigation considered that it was "surprising that the crew....did not cancel its take-off". The pilot stated that he had been aware of the F100 from his TCAS display and "

When giving the go around as the F100 approached the ILS DA, TWR instructed it to turn left immediately onto 050º because of the traffic which had taken off in front of it". It was found that once the left turn had been made, the flight paths of the two aircraft had diverged with both lateral and vertical separation between them increasing.

It was considered that "the fact that at no time during the approach by (the business jet) were the crew informed of the exit taxiway to use after landing" certainly contributed to their slow action in this respect, which had delayed the issue of take off clearance to the 737.

The formally documented Cause of the Serious Incident was stated as:

"Critical convergence between an aircraft in the final approach phase and an aircraft taking off, following inappropriate traffic management and the non-compliance with an order to abort take-off given by aerodrome control".

The Final Report was published on 9 April 2008. No Safety Recommendations were made.

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