Serious incident Piper PA-46-500TP Malibu Meridian HB-PRN, Saturday 18 February 2017
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Date:Saturday 18 February 2017
Time:11:34 UTC
Type:Silhouette image of generic P46T model; specific model in this crash may look slightly different    
Piper PA-46-500TP Malibu Meridian
Registration: HB-PRN
MSN: 4697437
Year of manufacture:2010
Fatalities:Fatalities: 0 / Occupants: 1
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:over Martigny -   Switzerland
Phase: En route
Departure airport:Les Eplatures Airfield (LSGC)
Destination airport:Lausanne-La Blécherette Airfield (QLS/LSGL)
Investigating agency: STSB
Confidence Rating: Accident investigation report completed and information captured
In the late morning of February 18, 2017, at Sion Airport the flight crew of the Global 6000, flight NJE8NJ, was ready for departure for a flight to Newcastle (EGNT). The GND controller at Sion announced this to the INS sector in Geneva in order to coordinate its take-off time. The flight plan foresaw a high performance SPR 2U Standard Instrument Departure (SID), one of the particularities of which is that it transits class E airspace.
After engine start, the flight crew of the Global NJE8NJ contacted the controller in the Sion tower at 11:24:04 UTC, who cleared them to taxi to the holding point on runway 25 almost 2 minutes later. At the same time, the Piper HB-PRN was at FL 150 between Lake Geneva and the city of Martigny. Its pilot was on a pleasure flight in the Alps, from Les Eplatures aerodrome (LSGC) to Lausanne-La Blécherette Airport (LSGL); he was in radiot contact with the Geneva FIC operator who had assigned him a transponder code.
At 11:28:26 UTC, the Sion Tower controller cleared NJE8NJ to line up on runway 25, then to take off with the instruction to call back at the altitude of 13000 ft in climb.
At 11:30:05 UTC, the Sion GND controller called the Geneva INS sector RP controller to inform him of the departure of NJE8NJ and to coordinate another IFR departure from Sion, also to the southwest. The latter then asked the controller to inform the NJE8NJ flight crew of a VFR flight flying southbound through Bex at FL 150, and then called the FIC operator to inform him that Sion air traffic control had been notified.
At 11:31:38 UTC, the FIC operator informed the pilot of HB-PRN that two IFR departures from Sion would take place shortly. The pilot then asked if he should change his route and the operator replied that he would call him back as soon as the IFR traffic was visible on his radar screen.
At 11:32:40 UTC, NJE8NJ appeared with the indication FL 099 on the radar screens of the INS sector and of the FIC operator. For operational reasons related to the mountainous topography of the area, the aircraft still had its flaps in takeoff configuration and climbed with a rate of climb of 3200 ft/min and an indicated airspeed of 170 kt. Its trajectory converged at right angles with that of HB-PRN. At 11:32:51 UTC, the approach of the two aircraft triggered the STCA short-term conflict warning, which displayed an alert on the radar screens of the INS sector and the FIC operator: NJE8NJ passed FL 104.5 at this moment and is at the horizontal distance of approximately 7 NM from HB-PRN.
At 11:32:57 UTC, the FIC operator reported this traffic to the pilot of HB-PRN, stating that it was at its 10 o'clock position, at a distance of 6 NM and that it was climbing through FL110. The pilot acknowledged, the FIC operator subsequently reported that the traffic was now at FL120 and would be passing in front of his track; the pilot informed that he was continuing on course.
At 11:33:13 UTC, the Sion ADC controller cleared NJE8NJ to continue climbing to FL 180 and requested that he contact Swiss Radar. The flight crew of NJE8NJ complied and reported to the new control sector (INS) that they were climbing through 13,000 ft towards FL 180. Radar data showed the aircraft passing FL 124 at a vertical speed of 3100 ft/min. The RE controller asked him to increase his rate of climb because of the presence of VFR traffic, for which he passed him traffic information.
At 11:33:46 UTC, the pilot of HB-PRN reported to the FIC that he had traffic on his TAS, 1500 ft below his altitude, at a distance of 2 NM, but that he had not acquired it visually.
At 11:33:48 UTC, the RE controller issued a new traffic advisory to NJE8JN regarding HB-PRN, stating that HB-PRN was at 2 o'clock, 1 NM. At the same time, a traffic advisory (TA) was issued by the TCAS of the Global NJE8NJ. It was followed by a corrective "down" Resolution advisory (RA) at 11:33:50 UTC, recommending to deviate from the current flight path by stopping the climb (TCAS spoken alarm "Level Off, Level Off"). The flight crew responded to the RE controller that they were leveling off due to a resolution advisory. The pilot of Piper HB-PRN was still unable to acquire the reported traffic and, thinking that it was converging on him, made a 180° right turn and at the same time descended 500 ft in about 10 seconds. Its trajectory approached tangentially to that of the Global NJE8NJ and the vertical separation between the two aircraft became less than 1000 ft. A corrective "down" resolution advisory (TCAS spoken alarm "Descend, Descend") then activated at 11:34:04 UTC on the Global NJE8NJ, which escalated 4 seconds later to a rate-of-descent advisory (TCAS spoken alarm "Increase Descent, Increase Descent"), the strength of which recommended increasing the rate of descent to a value greater than that recommended in the previous resolution advisory. The flight crew performed a downward evasive maneuver during which the aircraft descended to FL 132.5.
At 11:34:14 UTC, the two aircraft passed in close proximity to each other at 0.4 NM horizontally and 675 ft vertically.
At 11:34:20 UTC, on board the Global NJE8NJ, the resolution notice ended. During the downward evasive maneuver, the flight crew of the Global NJE8NJ tried to limit the increase of the indicated airspeed by deploying the spoilers, but could not avoid exceeding the maximum flaps extended speed (VFE). This overrun led him to keep the aircraft in its current configuration for the rest of the flight and to limit his cruising flight level to FL180. The flight was continued to the UK, but diverted to London Luton (EGGW).
The serious incident was caused by the unsafe approach in Class E airspace of two aircraft flying on perpendicular tracks, one in climb following a standard instrument departure, the other in level flight following visual flight rules.
The classification of the airspace as inappropriate for the topographical environment and the operations it encompasses played a role in the occurrence of the serious incident.

Accident investigation:
Investigating agency: STSB
Report number: 
Status: Investigation completed
Download report: Final report



Revision history:

06-Jul-2022 09:02 harro Added

Corrections or additions? ... Edit this accident description

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