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ASN Wikibase Occurrence # 236498
Last updated: 9 September 2021
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Time:09:45 LT
Type:Silhouette image of generic C172 model; specific model in this crash may look slightly different
Cessna 172R Skyhawk
Owner/operator:OSM Aviation Academy
Registration: SE-LZF
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:Stockholm/Västerås Airport (ESOW) -   Sweden
Phase: Approach
Departure airport:Västerås-Hasslo Airport (VST/ESOW)
Destination airport:Västerås-Hasslo Airport (VST/ESOW)
Investigating agency: SHK Sweden
A near collision occurred on 4 September 2019 in the airspace over the runway at Stockholm/Västerås Airport.
The aircraft involved in the incident were a Cessna 172R Skyhawk (SE-LZF) and a Piper PA-28 (SE- GVE).
The pilots detected each other’s aeroplanes at a late stage and performed avoidance manoeuvres. At the time of the incident, the airport was open and the navigation aids were functioning. However, the airport’s tower (TWR) was closed and the airspace uncontrolled (class G airspace).
AIP Sweden states that the airport’s terminal manoeuvring area (TMA) and control area (CTR) are only established during the tower’s hours of operation.
The Cessna 172 was being operated in accordance with an IFR flight plan and was performing repeated instrument NDB approaches to runway 01. The Piper PA-28 was being flown in accordance with a VFR flight plan and was on a training flight that encompassed navigation flying to the west of the airport and joined the traffic circuit for landing in accordance with the published VFR procedure.
The fact that the aeroplanes were adhering to different AIP procedures for IFR and VFR approaches, respectively, resulted in their flight paths crossing at the same altitude over the runway. Sensor data shows that both aeroplanes passed close to one another at about the same altitude and with a minimum horizontal separation of 150 metres (0.08 Nm). In addition, sensor data show that the Piper PA-28 made a sharp avoidance manoeuvre to the right just before the paths crossed.

Causes/Contributing Factors:
The incident was caused by the aeroplanes adhering to two different approach procedures with flight paths that crossed one another at the same altitude.
Several factors may have contributed to the incident. The window beam of the Cessna may, to a certain extent, have blocked the Cessna pilot’s view and thereby have contributed to late detection of the approaching PA-28. The Cessna pilot, who was flying in accordance with IFR rules, may be presumed to have been concentrating primarily on the flight and navigation instruments and not sufficiently on outward visual observations. Furthermore, the Cessna was below the horizon from the perspective of the PA-28, which may have made it more difficult for the pilot of the PA-28 to detect the Cessna earlier.
Another contributing factor may have been that the crew of the PA-28 did not fully understand the intentions of the Cessna because they did not have valid instrument ratings and therefore did not have knowledge of the format of the IFR procedures at the airport.



Accident investigation:
Investigating agency: SHK Sweden
Status: Investigation completed
Duration: 8 months
Download report: Final report


Revision history:

28-May-2020 15:36 harro Added

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