What aircraft was involved and where did it happen?

The accident on 2006-11-08 involved a C 172M, L 410 UVP, registration OK-FKD, at CTR LKPD, CZ.

Serious Incident between L-410 and Cessna 172M in Pardubice CTR (OK-FKD)

On November 8, 2006, a C 172M, L 410 UVP (registration OK-FKD) was involved in an aviation accident near CTR LKPD, CZ. Investigators recorded the probable cause as: The cause of the serious incident was the willful decision of the Cessna pilot, who without prior permission from air traffic control entered the sector of the ILS approach to RWY 27 of LKPD at a time when the L-410 was conducting an ILS approach to RWY 27. This summary draws on records from the Czech Air Accidents Investigation Institute (UZPLN).

On 8 November 2006, a serious incident occurred in Pardubice CTR when a Cessna 172M entered the ILS approach sector without clearance, resulting in a close proximity with a military L-410 on approach.

Event Description

On 8 November 2006, a serious incident involving a loss of separation occurred in the control zone (CTR) of Pardubice Airport (LKPD). The incident involved a Cessna 172M, registration OK-FKD, and a military L-410 UVP aircraft. The Cessna was conducting a VFR flight for aerial photography along a route from Hradec Králové (LKHK) via several waypoints. The L-410 was performing an IFR training flight from Pardubice to Brno (LKTB) and back, with an ILS approach to runway 27 at Pardubice.

According to radar recordings, the L-410 continued its ILS approach precisely along the descent path after passing the final approach fix. The pilot in command of the L-410 reported that he only noticed the other aircraft turning left towards his aircraft because he happened to be looking to the right at the co-pilot at that moment. The two aircraft passed each other at a lateral distance of approximately 100 meters and a vertical separation of approximately 30 meters.

Radar and Communication Analysis

Radar data from the MAPP and MP AR systems showed that both aircraft were identifiable throughout the incident: the Cessna as a primary target and the L-410 as a secondary target. Analysis of radiotelephony revealed that at 10:21:29, the Tower Controller (TEC) cleared the Cessna pilot to proceed to point Dašice and provided traffic information. The Cessna pilot acknowledged in a non-standard manner, which the TEC did not address. No further radio communication between the TEC and the Cessna occurred until 10:34:17, when the TEC asked if the pilot had seen the traffic.

The Approach Controller (EC APP) stated that he did not recall receiving traffic information from the TEC. He was working both the APP and PAR positions alone and assumed that the TEC knew about the ILS approach and would keep the area clear. He reported noticing the Cessna on radar around 10:23:37, close to the approach axis, but was checking wind data on a VAISALA instrument and did not react in time.

Cessna Pilot Actions

Radar data showed that at 10:22, the Cessna pilot, without clearance from the TEC, turned right from Dašice towards Pardubice city, flying about 2 km north of the runway 27 axis at 1000 ft AGL until approximately 6 km from the threshold. There, he made a left turn, bringing him into close proximity with the L-410 on the ILS approach. He then performed another 360° turn at about the same altitude before continuing toward the village of Moravany.

The Cessna pilot's response to the TEC at 10:21:29 did not confirm that he would follow the clearance or that he saw the traffic. From then until 10:34:17, he made no radio calls to report his actions or position. When asked by the TEC, he replied, "Yes, I saw it, it was about 30 m above me." The pilot stated he intended to inform the TEC of visual contact with the L-410 but was unable because the frequency was busy. However, recordings showed no radio traffic on the TEC frequency between 10:21:35 and 10:34:17. The Cessna pilot reported using SSR code 7000, but radar recordings did not capture any SSR code from the Cessna.

L-410 Crew Actions

The L-410 crew did not receive any traffic information from the EC APP during the entire approach maneuver. They had no awareness of the Cessna until the visual sighting just before the encounter.

Air Traffic Control Actions

The TEC issued a clearance and traffic information at 10:21:29 but did not follow up on the Cessna's non-standard reply or monitor its subsequent track. The EC APP, despite having both aircraft identifiable on radar, failed to inform the L-410 of the conflicting traffic and did not intervene as the situation developed.

Immediate Causes

According to the investigation, the immediate causes included:

The TEC cleared the Cessna to proceed to Dašice and provided traffic information, but the pilot acknowledged non-standardly without confirmation.
No further communication occurred until after the incident.
The EC APP did not inform the L-410 of other traffic in the CTR.
The EC APP was working alone and did not react despite radar visibility.
The Cessna pilot turned without clearance and entered the ILS approach sector.

Contributing Factors

The investigation identified the following contributing factors:

The EC APP did not react to the developing situation even though both aircraft and their trajectories were identifiable on the APP and PAR radar displays, and he did not notify the aircraft on the ILS approach of the other traffic.
Insufficient action by the TWR LKPD, who after issuing the last clearance for the Cessna did not further inquire about its flight path.

Probable cause

The cause of the serious incident was the willful decision of the Cessna pilot, who without prior permission from air traffic control entered the sector of the ILS approach to RWY 27 of LKPD at a time when the L-410 was conducting an ILS approach to RWY 27. Contributing factors were the lack of reaction from EC APP despite identifiable radar tracks, and insufficient action by TWR LKPD.

2006-11-08: C 172M, L 410 UVP (OK-FKD) — CTR LKPD, CZ