Celebrations to mark the arrival of a Saudia Airbus A320 service to Dubai misfired when a ceremonial firefighters’ water-arch punched out an overwing exit and caused its evacuation slide to deploy.
United Arab Emirates investigators have disclosed that the aircraft (HZ-AS55) had arrived from Jeddah on 20 September last year.
As the A320 taxied to gate C58 it passed between two firefighting vehicles positioned to spray a traditional welcoming water-cannon salute over the aircraft, to mark the Saudi Arabian national day which falls on 23 September.
But the vehicle on the left side of the aircraft – a Rosenbauer Panther 8x8 – experienced a problem with its roof turret, says the UAE’s General Civil Aviation Authority.
It says the turret “ceased to follow the operator’s input from the hand controller” which resulted in the high-pressure water jet initially spraying upwards, then downwards, as the aircraft passed.
The water jet struck the aircraft’s mid-fuselage and the overwing exit, knocking it into the cabin and causing the evacuation slide to deploy and inflate.
Pilots of the aircraft, which had 126 occupants, received a master warning and brought the A320 to an immediate halt.
“They were not aware that a water salute had been arranged on arrival at the gate and therefore they could not inform the cabin crew or passengers prior to the event,” says the inquiry.
One of the 119 passengers, sitting adjacent to the emergency exit, sustained minor injuries when the 15kg hatch fell inwards.
The aircraft was towed to the gate, where the passengers disembarked and the slide was detached.
Inspectors examined the overwing exit door and the aircraft’s fuselage, determining that no structural damage had occurred, and the hatch was re-installed.
The A320 subsequently departed Dubai, nearly 6h after the incident, under an engineering authorisation permitting a single flight without the overwing slide fitted. The A320 has two overwing exits.
Cirium’s Fleets Analyzer lists the aircraft involved as a 2017 airframe powered by CFM International CFM56 engines.
Inspection of the firefighting vehicle determined that a fault in an elevation-control potentiometer on the control handle caused the mishap.
Water salutes, while “accepted practice” for special events, remain a “non-normal” activity, says the inquiry, which found evidence of aircraft damage during a review of previous incidents.
It adds that the intent of the salute was “poorly communicated” and left the aircraft crew in an unexpected situation where they had to react to unpredictable external events.
“They followed known procedures to the best of their knowledge and the information available to them at the time,” it says.