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L410, Dubrovnik Croatia, 2018

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Summary
On 29 November 2018, a Let 410 landed on a temporarily closed section of the runway at Dubrovnik after a visual approach in benign weather conditions. The Investigation found that the flight crew had not carried out a sufficient pre-flight review of current and available information about a major multi-phase runway reconstruction there which they were familiar with. The opportunity for better advance and real time communication with aircraft operators and their flight crew and the benefit of the recommended ‘X’ marking at the beginning of any temporarily closed part of a runway, omitted in this case, was noted.
Event Details
When November 2018
Actual or Potential
Event Type
Controlled Flight Into Terrain (CFIT), Human Factors
Day/Night Day
Flight Conditions VMC
Flight Details
Aircraft LET L-410/420
Operator Van Air Europe
Domicile Czech Republic
Type of Flight Public Transport (Passenger)
Origin Split/Kastela
Intended Destination Dubrovnik Airport
Take off Commenced Yes
Flight Airborne Yes
Flight Completed Yes
Flight Phase Landing
LDG
Location - Airport
Airport Dubrovnik Airport
General
Tag(s) Inadequate Airport Procedures,
Copilot less than 500 hours on Type,
Visual Approach
CFIT
Tag(s) Undershoot on Landing
HF
Tag(s) Data use error,
Plan Continuation Bias
Outcome
Damage or injury No
Causal Factor Group(s)
Group(s) Aircraft Operation,
Air Traffic Management,
Airport Operation
Safety Recommendation(s)
Group(s) Aircraft Operation,
Air Traffic Management,
Airport Management
Investigation Type
Type Independent

Description

On 29 November 2018, a Let 410 (OK-LAZ) being operated by Van Air Europe on a scheduled domestic passenger flight from Split to Dubrovnik for Trade Air as TDR821 made an uneventful day VMC approach to runway 12 at destination but then landed within the confines of an unmarked and notified closed part of the runway. After coming to a stop without encountering obstructions, the aircraft was instructed to await guidance before attempting to taxi due to obstructions ahead and complied. There were no injuries to the 10 occupants and no damage was caused to the aircraft.

Investigation

After prompt notification of the event from both the Dubrovnik Airport and Croatia Control, the Croatian Air, Maritime and Railway Traffic Accident Investigation Agency (AMRTAIA) began an Investigation the same day. It was noted that the aircraft involved was fitted with a CVR and an FDR but there was no reference to the downloading of relevant data or use of such data by the Investigation or to inform the internal investigation carried out by the aircraft operator.

It was noted that the Captain (born in 1959), had been PF for the flight and was a Slovenian national. He had a total of 7,110 flying hours of which 5,880 hours were on type and had begun his career as a civil pilot after 27 years as a military pilot. Prior to the investigated event, he had made 17 flights to Dubrovnik between May and November 2018. The First Officer (born in 1979) was a Czech national. She had a total of 466 flying hours of which 193 hours were on type.

It was further noted that the aircraft operator involved, Van Air Europe is an ACMI (Aircraft, Crews, Maintenance, Insurance) contractor to Trade Air who in turn hold a contract to provide domestic air service in Croatia on Public Service Obligation (PSO) routes. It was noted that in February 2017, the same Van Air Europe aircraft that was involved in the event being investigated “was involved in another Serious Incident, the Investigation into which had concluded that the crew decided to land in conditions of strong wind with a lateral component of twice the permissible limit for the aircraft in question (and that) following this incident, the UK Civil Aviation Authority suspended the authorisation for Van Air Europe aircraft to operate in the UK”.

It was found that at the time of the event a major runway reconstruction project was under way at Dubrovnik where, when fully operational, the single runway would have been 3,300 metres long and 45 metres wide. At the time of the event the longitudinal profile of the runway in its 12 direction was characterised by a brief and minor upslope until the TDZ followed by a minor negative slope thereafter. The reconstruction project had commenced at the beginning of November 2018 and was due to be completed in mid March 2019. At the time of the investigated event, Phase 2 of the project was under way and involved the work over the full width of 1732 metres of the northwest and central parts of the runway. This resulted in the length of runway remaining available for operational use being reduced to 1425 metres at the southeast end - see the illustration below. A NOTAM in respect of Phase 2 of the project had been issued with a commencement date of 25 November 2018 and whilst it referred to the Runway 12 and its IAPs, it gave no other detail and merely referred to AIP SUP 013/2018 being in force from the same date and it was this document which contained the detail on runway closure.

Phase 2 of the runway reconstruction works (construction area shown cross hatched in red). [Reproduced from the Official Report]

What Happened

On the day of the event, the aircraft and flight crew involved were to operate six flights over an 11 hour period of which the Split-Dubrovnik sector was the third. Prior to the first flight, the Captain stated that he had reviewed relevant NOTAMs and had “noted information on permanent construction works and the shortened runway at Dubrovnik but […] he had failed to notice the information about the displaced runway threshold”. The Investigation noted too that “the flight crew had not thoroughly examined the more detailed information on the construction works which was contained on available Jeppesen Airport Cards”, which included reference to the displaced runway 12 threshold.

The flight from Split to Dubrovnik Airport proceeded normally and the Captain subsequently stated that during the landing briefing for runway 12 “he did not realise that the runway threshold had been displaced and which portion of the runway was being used”. Once an approach to runway 12 had been approved by ATC, he reported having “descended the aircraft at the standard descent rate for a visual approach, without checking the procedure for the instrument approach to the runway 12”. It was noted that no comment in relation to the displaced runway threshold in operation was made by ATC at any time during the approach. The Captain stated that the descent profile he had flown was in fact shallower than necessary and considered that “due to the curvature of the runway and the construction machines in the middle of the runway”, he had failed to see the displaced threshold lights or the relocated PAPI and that had he done so, it “would have helped him to understand the situation”. It was reported that these were both illuminated.

When the First Officer said (twice) during the approach that she could “see construction vehicles in the middle of the runway”, the Captain had responded that “the situation was the same runway as last week without realising that the working machines were much closer than before, and that they were operating in the middle of the runway”. He stated that “during the entire approach there was no activity on the closed portion of the runway from which it could be concluded that something was different”. He said that although he had seen that there were no markings on the runway (nor was there a white ‘X’ to indicate closure) he had thought this was because of current construction work (Phase 1 of which, involving the opposite half of the runway, had been in progress the previous week). He stated that he had informed both Van Air Europe and Trade Air about the event after completing all flights that day.

The First Officer stated that the reduction in runway length to 1424 metres was included in the ATIS and that they both knew this was the case but that it did not make it clear which runway had a displaced landing threshold. She also noted that the vehicles she had seen on the runway were towards the middle of the runway and that the first part of the closed area had been completely free of obstructions. However, before being guided off the closed runway, they had to wait for “smaller rocks” to be removed from their exit route.

After the event the Airport Operator reviewed their compliance with the project planning document in respect of Phase 2 in matters which might have been contributory to the actions of the flight crew. They found only that after three days of heavy rain since all surface painted markings on the closed runway area had been obscured, this covering had slightly faded to the extent that it was just possible to discern limited evidence of parts of the obscured markings. However, it was also recognised that there was scope for better advance communication with aircraft operators using Dubrovnik on any temporary non-availability of parts of the manoeuvring area.

The Investigation considered the arrangements made for visually communicating non-availability of part of the normally available runway. It was noted that ICAO Annex 14 and other guidance documents stated that a white ‘X’ marking is not necessary if a runway or part of it “is only closed for a short duration and when the information on its closing information is published by an adequate warning issued by the AIS provider” but that they also “do not define the meaning of the terms ‘short duration’ or ‘adequate warning’. The Investigation was informed that the closed marking ‘X’ was not placed since the entire closed area was the construction site where the pavement surface was being removed”. However, it was noted that such temporary ‘X’ markings are usually not painted but provided using tailored fabrics secured by pavement fasteners or mounted on a portable structure.

The Conclusions of the Investigation included, but were not limited to, the following remarks:

  • The regulatory standards applicable to the subject event are not precisely defined in certain areas, which leaves certain freedom to the organisations involved to define specific conducts, such as applying horizontal markings or defining information to be transmitted via ATIS or through controller via radio.
  • Flight preparation is an important segment when it comes to the safety of the flight itself. The information provided to the flight crew during preparation has a significant impact on flight decisions. In the present case, it was established that the preparation was inadequate for the subject flight. The level of complexity in the documentation which flight crews review during flight preparation can make it difficult to understand certain information by the crew, especially if the flight crew operates several flights in a row. In such cases, an additional role in preparation of the flight itself can be assumed by the operations centre of the operator, which by its action can alert the flight crew to certain risks and dangers.

The Immediate Cause of the investigated Serious Incident was determined as “the failure of the aircraft commander to identify the active portion of the runway and the closed portion of the runway”.

Five Contributory Factors were also identified as:

  • Inadequate flight preparation by flight crew.
  • A visual approach below the ideal aircraft path.
  • Non-marking of the closed portion of the runway with an “X” in accordance with the applicable recommendations.
  • Partial visibility of the previously obscured horizontal markings on the portion of the runway, which was out of use.
  • Lack of information on the displaced runway 12 threshold on the ATIS broadcast and/or in information given to the aircraft in question by the air traffic controller.

Safety Action to be taken by Dubrovnik Airport to reduce the risk of further similar events was identified as:

  • Direct advance notification to all aircraft operators using the airport of temporary changes to normal availability of the manoeuvring area.
  • Continuously monitoring any temporarily closed part of a runway to ensure that compliance with all planned risk mitigation measures is maintained.

Seven Safety Recommendations were made as a result of the Investigation as follows:

  • that Van Air Europe should define procedures that will enable its flight crews to more easily review specifics of NOTAM information, especially when NOTAM information refers to other complex documents such as an AIP-SUP. [AIN04-SR-17/2019]
  • that Van Air Europe should implement all the corrective measures specified in its own analysis of the subject event. [AIN04-SR-18/2019]
  • that Dubrovnik Airport should introduce procedures which include the use of the horizontal runway closure marking “X” as the first safety measure which would warn the pilots about the status of a manoeuvring surface (and) such markings should be present until the manoeuvring area is available for use. [AIN04-SR-19/2019]
  • that Dubrovnik Airport should include in its internal procedures the measures M1 and M2 defined in their document “Analysis of the event related to safety MOR29NOV2018” of the subject event (and) such measures should become standard practice at Dubrovnik Airport. [AIN04-SR-20/2019]
  • that Croatia Control should, in cases where a runway threshold is displaced, use the term “displaced threshold” in information published via ATIS and/or information issued by the controller to aircraft on approach. [AIN04-SR-21/2019]
  • that the Croatian Civil Aviation Agency should, when approving airport construction and reconstruction projects, fully verify compliance of the project with the requirements of ICAO Annex 14 and of EU Regulation CS-ADR-DSN related to horizontal marking of manoeuvring areas. [AIN04-SR-22/2019]
  • that the Croatian Civil Aviation Agency should, during the performance of construction works at airports, increase the number of supervisions in order to verify compliance of construction works with the approved documentation which specifies “Management of Airport Operations During Construction Works”. [AIN04-SR-23/2019]

The Final Report was completed on 29 April 2020 and subsequently released to unlimited access.

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