Description

On 18 September 2018, an Airbus A320 (A6-ANV) being operated by Air Arabia on an international passenger flight from Sharjah to Salalah as ABY111 which was being used for line training turned the wrong way when entering the runway in normal day visibility and began takeoff with insufficient runway length available. The lightly loaded aircraft did not become airborne until it had departed the end of the runway and entered the RESA after which the landing gear struck an approach light damaging the tyre involved. It then continued without further event to its intended destination and continued to complete the return flight with the damaged tyre remaining inflated and the damage reportedly not visible with the wheel concerned positioned during the turnround.

Investigation

An Investigation was carried out by the UAE GCAA Air Accident Investigation Sector (AAIS). Data from both the FDR and the CVR were downloaded but relevant data from the CVR had been overwritten. 

It was found that the 51 year-old Training Captain in command had a total of 22,184 hours flying experience including 15,536 hours on type and had been acting as PM for the investigated departure. He was accompanied by a 34 year-old Second Officer under training who had a total of just 159 hours flying experience, all of which had been gained on type as she progressed through the fifth and final stage of the operator’s MPL-based ab-initio pilot training programme. At this stage of her training, company procedures did not require a third pilot to occupy the flight deck supernumerary crew seat during flights. The event under investigation occurred on the fourth day of line/route training conducted with the same crew pairing.  

What Happened

It was established that pre fight preparation was unhurried and apparently thorough and included the Second Officer being briefed that she would be PF and that the taxi out would be on a single engine with the second started nearer the runway. The brief also included the planned intersection and rolling takeoff “as part of her training subjects”. 

The speeds used for a 57 tonne takeoff using reduced thrust were V1, 122 KIAS, VR, 127 KIAS and V2, 129 KIAS. All relevant flight performance data, including the flap/slat setting and the runway in use - runway 30 - were correctly entered in the FMS. In line with the aircraft operators procedures the ‘V’ speeds used were provided on the OFP rather than calculated by the crew. The OFP stated that from the intersection to be used, B14, the TODA would be 3,050 metres. The ASDA in the event of a rejected take off was not provided which was approximately 1,000 metres shorter that the full length of the runway.

During pushback, the left engine was started by the Captain. Taxi clearance was then given as taxi for runway 30 at B14 via taxiways A & A14 and contact TWR on reaching the holding point. After about a minute of taxi time, the right engine was started as the aircraft approached the B14 intersection. With the park brake set, the Before Takeoff Checklist (see the illustration below) was completed ‘down to the line’.

The Before Takeoff Checklist. [Reproduced from the Official Report]

The Captain called TWR and advised ready for departure and on receiving takeoff clearance read it back “Clear for takeoff, Bravo fourteen, Runway three zero Arabia triple one. Thank you”. The Second Officer then requested completion of the paused checklist which includes confirmation of the runway by both pilots. 

As this was being read by the Captain, the parking brake was released and after a few seconds rolling forward towards the runway at idle thrust, the Second Officer then began to increase both engines' thrust above idle power and commenced a right turn towards runway 12, the reciprocal direction of the runway. The Captain stated that at this time “his sight was directed inside the flight deck completing the remaining items on the Before Takeoff Checklist”. 

The runway 12/30 access from B14 showing the taxi lines and the runway 30 TDZ markings. [Reproduced from the Official Report]

Without any intervention from the Captain, the Second Officer then advanced both thrust levers to the FLX/MCT position. After checking thrust was set, she reported noticing that the Flight Mode Annunciator (FMA) was showing ‘NAV’ instead of ‘RWY’ and called this out. Soon after this call, the Captain looked up and realised that the aircraft was accelerating in the wrong direction but “decided to continue the takeoff believing that the remaining take-off runway available was insufficient to reject the takeoff” and advanced the thrust levers to TOGA. FDR data indicated that this action occurred at 57 KCAS and 63 knots ground speed with 730 metres of runway remaining with TOGA thrust reached within 2 seconds. The Second Officer continued to apply a nose down sidestick input of 6°.

After a further six seconds, TWR saw what was happening and called the flight with no response. The Captain then moved the slat/flap to the ‘flap 2’ position and initiated rotation at VR-8 by making a nose up sidestick input recorded as initially 8.3° which then increased to 9.2°. FDR data showed that although the Captain had clearly taken control, he had not taken sidestick priority so that the Second Officer’s continuing nose down sidestick input, albeit reduced to 3° was being summed with the Captain’s opposing input. The aircraft pitch-up angle reached 9.1° and the aircraft lifted off at 132 KCAS - equivalent to 140 knots ground speed given the tailwind takeoff. The aircraft had continued beyond the end of the runway into the RESA by about 30 metres. The illustration below shows the takeoff diagrammatically. 

An annotated reconstruction of the aircraft ground track. [Reproduced from the Official Report]

Although not known to the crew at the time, the No. 3 main gear wheel had struck and damaged one of the runway approach lights. A further call from TWR as the aircraft climbed through 260 feet agl received a response from the Captain who subsequently passed control back to the Second Officer and the intended flight was completed. 

In his interview, the Captain stated that after arriving at Salalah, he was contacted by company Operations Control and a discussion took place about the return sector. As he stated that he was unaware of any aircraft damage, he decided to operate the flight as planned and subsequently did so as PF.

It was concluded that in all probability, neither of the calls which the Captain was required to make when taking control - “I have control” - and when deciding to continue the takeoff - “Go” - or any equivalent verbal communication had occurred. 

Discussion Points

• The Investigation team asked Airbus to establish whether the Captain could have completed a rejected takeoff without a runway excursion taking into account the dry runway surface, the takeoff weight, configuration and performance and the prevailing wind velocity in two scenarios:
  • By applying maximum reverse thrust at the time the Captain had selected TOGA at 57 KCAS.
  • By applying maximum reverse thrust at the time when the Captain had selected flap 2 configuration at 109 KCAS.
• Based on the Airbus calculation that, at the time the takeoff was initiated, there was 984 metres of runway remaining, it was found that it would have been possible to safely stop the aircraft on the runway in both cases if maximum engine reverse thrust was used and MAX autobrake was selected (which it was). For the first scenario, it was calculated that the aircraft would have stopped 653 metres before the end of the runway and for the second scenario, the aircraft would have stopped 45 metres before the end of the runway.
• The Investigation noted the existence of two ‘safety systems’ either of which would, had they been installed, have provided aural alerting of the runway line up error before FLEX/MCT thrust was selected:
  • The Runway Awareness and Advisory System (RAAS) - A Honeywell product which includes alerts to pilots for potential short runway takeoffs. 
  • Takeoff surveillance and performance analysis (TOS2) - An Airbus product which Airbus concluded would have triggered the ECAM caution ‘NAV NOT ON FMS RUNWAY’ as the aircraft lined up in the wrong direction and the ECAM warning ‘T.O RUNWAY TOO SHORT’ since the required takeoff distance as configured was 1,145 metres, more than the 1,000 metres available.  
• The Captain’s post takeoff decision making was considered flawed in respect of:
  • The decision to continue the flight to the intended destination rather than return to Sharjah since it was not based on an appropriate risk assessment of the degraded performance of the Second Officer.
  • The failure to report the event to Sharjah TWR
  • The failure to report the event the Company Operations Control Centre.
• Although not proven, it was considered that the presence of a sign at intersection B14 showing the TORA in each runway direction may have prevented the event. It was noted that such a sign is envisaged in the CARs in the event of “operational need”.

The formal statement of Cause of the event was determined as "the First Officer steering the aircraft to the right onto the wrong runway during a rolling takeoff (with) entry to the wrong runway due to degraded situational awareness of the aircraft direction by both pilots due to lack of external peripheral visual watch and runway confirmation”.

One Contributing Factor was also identified as “the air traffic controller did not monitor the aircraft movement after takeoff clearance was given”.

A total of 6 Safety Recommendations were made as a result of the Investigation as follows:

• that Air Arabia carry out a risk assessment for single engine taxi considering the estimated taxi time and operation environmental conditions to determine mitigation measures accordingly. [SR41/2021]
• that Air Arabia establish a safety case to determine the possibility of enhancing A320 alert systems with the installation of taxiway and runway detection systems that will aid pilots’ situation awareness. [SR42/2021]
• that Air Arabia use this Incident to reinforce to the pilots the significance of flight preparation briefing; positive runway identification; significance of knowing runway signage, markings and distances; effective crew resource management during taxi and takeoff; and safeguarding the aircraft and occupants when making the decision to reject a takeoff based on low and high speed regimes. [SR43/2021]
• that Air Arabia enhance take-off speed calculations procedure for the flight crew by involving them in these calculations to ensure that they are fully aware of the performance requirements for stopping an aircraft on the runway. [SR44/2021]
• that Air Arabia include in the Operations Manual Part A (OM-A) a policy for crew resource management following degraded pilot capability not categorised as incapacitation. [SR45/2021]
• that Sharjah Air Navigation Service (SANS) explore the possibility of re-evaluating the risks surrounding intersection takeoffs following this Serious Incident and prepare a safety case study, if needed, to prevent similar incidents from occurring. [SR46/2021]

The Final Report of the Investigation was issued on 10 January 2022.

Related Articles

• Runway Excursion
• Take Off Distance Available (TODA)
• Takeoff Run Available (TORA)
• Runway End Safety Area
• Aircraft Performance
• Crew Resource Management (CRM)
• Runway Awareness and Advisory System (RAAS)
• Intersection Take Off: Guidance for Controllers
• Intersection Take Off: Guidance for Flight Crews