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ASN Wikibase Occurrence # 208088
Last updated: 1 December 2021
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Time:08:02 LT
Type:Silhouette image of generic PA31 model; specific model in this crash may look slightly different
Piper PA-31-350 Navajo Chieftain
Owner/operator:Jonair Affärsflyg
Registration: SE-FNE
MSN: 31-7405434
Fatalities:Fatalities: 0 / Occupants: 6
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:Kokkola-Pietarsaari Airport (KOK/EFKK) -   Finland
Phase: Landing
Departure airport:Skellefteć
Destination airport:Kokkola/Pietarsaari-Kruunupyy Airport (KOK/EFKK)
Investigating agency: SIAF
Jonair flight JON01 from Skellefteć landed at Kokkola-Pietarsaari Airport (EFKK) on a runway which was occupied by runway maintenance vehicles.
At 07:49 EFKK air traffic control (ATC) permitted runway maintenance vehicles to enter Runway 19. Almost simultaneously JON01 contacted the ATC, which then issued an approach clearance and said that runway maintenance was in progress and that it might cause some delay. JON01 replied that a narrow, cleaned section of the runway would be sufficient for landing. At that point the pilots were witnessing light icing. At the time of the occurrence it was snowing heavily, visibility was approximately 1000 m and the cloud base was at approximately 200–500 ft (60–150 m).
At 07:54 JON01 requested a short approach. At 07:56 the ATC replied that it would take approximately 10 more minutes for runway maintenance to be completed. JON01 replied that they could not wait that long because there was icing at every layer. At the same time the air traffic controller permitted the runway friction measuring vehicle to enter the runway. The air traffic controller told JON01 that there was very much snow on the runway to which JON01 replied that they would like to attempt an approach or, otherwise, be forced to make a missed approach owing to the icing conditions. The pilots also considered returning to Skellefteć, from where they had departed.
At 07:57 the ATC issued an approach clearance and, a moment later, requested that JON01 report passing the final approach fix. At 08:00 JON01 requested the ATC to confirm that the high-intensity runway approach lights were on full intensity. There was no reply and the pilots repeated the request twice. The person measuring the runway surface friction was speaking at the same time on the loudspeaker, making it difficult for the air traffic controller to hear anything else. Transmissions were simultaneously coming in on the ground frequency and the aviation frequency. As the ATC’s and JON01’s transmissions were partly overlapping, the air traffic controller could not make out what JON01 was saying. The air traffic controller assumed that they had reported passing the final approach fix, at which time the controller told JON01 to go around.
The co-pilot of JON01 consulted the captain about going around. The captain replied that it was necessary for them to land because of the icing and that, according to his account, he believed that they were cleared to land. The ATC asked whether JON01 had received the order to go around. JON01 replied that they would land if the runway was free. Rather than issuing a landing clearance the air traffic controller again ordered JON01 to go around because there were three maintenance vehicles on the runway.
When the airplane broke through the cloud the pilots made visual contact with the runway, at which time they also spotted the vehicles on the runway. JON01 immediately told the ATC that they had to land in front of (i.e. before reaching) the vehicles. At 08:02 JON01 flew over the friction measuring vehicle which was in the centre of the runway at the location of the precision approach lights. Then they landed on the left side of Runway 19 on a section which had not been cleared of snow, passing the runway maintenance vehicles from the left. The air traffic controller warned the vehicles of the aircraft when it was already in the landing phase. The snow plume raised by the maintenance vehicles degraded runway visibility. The incident did not result in any injuries to persons or damage to material.

The investigation revealed that the radio phraseology used by the parties did not entirely comply with regulations, nor was it sufficiently clear-cut. The radio equipment used by the ATC made it possible for the airport ground frequency transmission on ATC speakers to be overheard on the aviation frequency, which interfered with the radiocommunication between the flight crew and the air traffic controller. Moreover, the ATC’s and JON01’s transmissions partially coincided with each other. The pilots did not report passing the final approach fix, nor could the air traffic controller, with their existing system, monitor the position of the aircraft during the final stages of the approach. Neither did the flight crew sufficiently clearly describe the effects of the icing on the airplane’s performance and so the air traffic controller was unaware of the severity of the icing.

The air traffic controller had little experience in coordinating runway winter maintenance and air traffic. The co-pilot’s ability to evaluate the situation and support the captain was limited. This was the co-pilot’s first flight in the company; it was carried out as a line training flight for him. The co-pilot had no prior experience of flying in icing conditions.

Weather at the Kokkola Airport during the morning:
EFKK 221120Z 34012KT 300V010 5000 -SN FEW005 SCT008 BKN010 OVC013 M01/M02 Q0995
EFKK 221050Z 34009KT 310V020 2000 -SN FEW004 SCT009 BKN014 OVC017 M01/M02 Q0994
EFKK 221020Z 33010KT 2000 -SN FEW003 SCT006 BKN008 OVC010 M01/M01 Q0994
EFKK 220950Z 32008KT 280V360 3400 -SN FEW003 SCT006 BKN008 OVC011 M01/M01 Q0993
EFKK 220920Z 32007KT 280V350 3400 -SN FEW003 BKN006 OVC009 M01/M01 Q0993
EFKK 220850Z 33008KT 290V360 8000 RASN FEW004 BKN006 BKN009 OVC011 M00/M01 Q0993
EFKK 220820Z 31008KT 280V360 3500 RASN FEW003 SCT005 OVC007 00/M01 Q0992
EFKK 220750Z 30006KT 270V350 1500 RASN SCT003 BKN006 OVC010 00/M00 Q0992


Accident investigation:
Investigating agency: SIAF
Status: Investigation completed
Duration: 10 months
Download report: Final report


Photo of SE-FNE courtesy

Aalborg (EKYT / AAL)
17 May 2006; (c) Erik Frikke

Revision history:

23-Mar-2018 19:38 penu Added
23-Mar-2018 19:41 harro Updated [Narrative]
04-Apr-2018 16:36 penu Updated [Registration, Operator, Source, Narrative]
04-Apr-2018 20:05 penu Updated [Source, Narrative]
12-Apr-2018 07:10 penu Updated [Source, Narrative]
12-Apr-2018 08:23 penu Updated [Source]
23-Jan-2019 20:44 harro Updated [Time, Operator, Departure airport, Destination airport, Narrative, Accident report, ]

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