ASL Belgium B734 at Porto on Apr 27th 2021, cleared for takeoff despite vehicle on runway
Last Update: December 30, 2022 / 15:58:31 GMT/Zulu time
Incident Facts
Date of incident
Apr 27, 2021
Classification
Incident
Airline
ASL Airlines Belgium
Flight number
3V-4959
Departure
Porto, Portugal
Destination
Liege, Belgium
Aircraft Registration
OE-IAJ
Aircraft Type
Boeing 737-400
ICAO Type Designator
B734
About 12 minutes earlier tower had cleared a follow me vehicle to perform the nightly runway inspection. The vehicle entered runway 35 and worked northbound reaching the threshold runway 17. The vehicle turned around to now move southbound when the driver saw bright white lights near the threshold of runway 35 which seemed to move and queried with tower whether an aircraft was lining up runway 35. Tower reported an aircraft was in their takeoff run and instructed the vehicle to immediately vacate the runway via the left runway edge.
The Boeing crew saw two white lights but weren't sure whether these were runway edge lights due to the night environment. After becoming airborne and in the climb the crew queried with tower about the vehicle and received a reply, that this was a misunderstanding.
Portugal's GPIAA reported according to estimation by the vehicle driver as well as preliminary analysis of the ground radar the separation between the vehicle and aircraft reduced to 300 meters. The occurrence was rated a serious incident and is being investigated by the GPIAA.
On Dec 30th 2022 the GPIAA released their final report concluding the probable causes of the serious incident were:
- The provision of air traffic services with unified tower and approach positions, provided by a single controller without any supervision, working in continuous duty without interruptions for an extended period of time, in a tedious and low-activity environment.
- Archaic memory aid system, ineffective and totally dependent on human action to prevent simultaneous use of the runway by vehicles and aircraft.
- An inactive RIMCAS system.
- Decision process on the application/inhibition of technological tools, in particular the inhibition of RIMCAS, without a risk analysis supported by facts or mitigation measures to allow such inhibition.
- The absence of advanced ATC surveillance systems, including multilateration and electronic flight strips which can offer additional protection when compared with traditional, entirely human-dependent systems.
- The absence of H24 stop bars procedure or other equivalent lighting systems at all runway holding positions, as recommended by EAPPRI for ANSPs.
- Absence of objective criteria set by the organisation for the tactical management of teams by supervisors, based on risk assessment in order to ensure that the required level of safety is not compromised.
- ANSP deficient organisational culture, resulting in misrepresentation of the position logs not in line with reality.
- NAV Portugal’s failure to oversee and detect operational, managerial and safety shortcomings over the different Units, namely at Porto and Ponta Delgada towers.
- Deficiencies in NAV Portugal’s safety management system, just culture and its compliance with the requirements of Part-ATS were not identified by the regulator.
- Regulator’s shortfall in properly supervising the Runway Safety Committees at Porto and Ponta Delgada airports, ensuring effectiveness of their activities and compliance with Regulation 8/2018.
- The lack of a single frequency for all aircraft and vehicle movements in the manoeuvring area (as recommended by EAPPRI, and others) which would allow both flight crew and ground vehicle drivers to be aware of any possible threats to safety.
- Unreliability of the radio scanners which were installed by the infrastructure management in the Follow-Me vehicles at Porto airport, which were not user friendly and for which no formal training had been given to the drivers on how to operate them.
- The Follow-Me driver’s decision not to actively monitor the aeronautical frequency even though it was not a mandatory requirement.
- The non-standardised manner of conducting the runway inspections which, in this case, resulted in a prolonged period of TETRA radio silence.
The GPIAA annotated that this conclusion is also valid for another occurrence, see Incident: TAP A21N at Ponta Delgada on May 13th 2022, cleared to land on occupied runway.
Incident Facts
Date of incident
Apr 27, 2021
Classification
Incident
Airline
ASL Airlines Belgium
Flight number
3V-4959
Departure
Porto, Portugal
Destination
Liege, Belgium
Aircraft Registration
OE-IAJ
Aircraft Type
Boeing 737-400
ICAO Type Designator
B734
This article is published under license from Avherald.com. © of text by Avherald.com.
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