Description

On 6 November 2017, an Embraer ERJ190-100LR (CS-TPV) being operated by Portugalia on a scheduled international passenger flight from Nice to Lisbon lined up on the taxiway parallel to runway 04L and, when cleared, commenced takeoff on it without the TWR controller noticing. By the time he did notice, the aircraft had travelled about 550 metres and was continuing to accelerate above 85 knots at which point he cancelled the takeoff clearance and the aircraft stopped without any consequences. Ten minutes later, the flight departed from the runway and was completed without further event.

Investigation

An Investigation was carried out by the French Civil Aviation Accident Investigation Agency, the BEA. Recorded ATC data and FDR data were obtained but the CVR data was not preserved even though the Captain stated that he had been aware that the event would be subject to investigation as a Serious Incident as he had “not thought about it”.

It was found that the 54 year-old Captain, who had been PF for the flight, had a total of 12,003 hours flying experience but only 555 hours in command on type, having been promoted to command the previous year after being employed as a pilot by Portugalia for 17 years. The 62 year-old First Officer had a total of 14,530 hours flying experience of which 739 hours were on type. He had been employed as a pilot by Portugalia for 27 years. Both pilots had made frequent flights to Nice - in 2017, the Captain had made 16 such flights and the First Officer 20 and so were familiar with the manoeuvring area at Nice. The TWR controller in position had fifteen years’ experience as a controller and after being posted to Nice in 2011, had been qualified as a TWR controller there since 2012.

What Happened

The flight departed from its parking stand (position 1 in the illustration below) more than an hour late with a west-facing push-back onto taxiway ‘T’ with the Captain acting as PF. The GND controller then cleared the flight to taxi via taxiways ‘T’ and ‘A’ (position 2) to holding point ‘A1’ for a takeoff from 45 metre-wide runway 04L. The First Officer read back the taxi route but did not mention the clearance limit also given. One minute later and prior to beginning to taxi, the crew requested confirmation of the taxi route which was provided. They then began taxiing along taxiway ‘T’, started the second engine (position 3) and carried out the flight controls check (position 4). As the aeroplane approached the end of taxiway ‘T’ (position 4), the crew reported that they were at holding point ‘A1’ and ready for departure and the GND controller asked them to contact TWR. At this point, the aircraft was actually still 350 metres away from the clearance limit given and abeam a sign which indicated that taxiway ‘A’ was to the left. The GND controller subsequently stated that he had not checked the position of the aeroplane on the ground radar because he was focused on looking out for a police car which he was expecting after a request for police attendance by an inbound flight.

The annotated ground track of the aircraft derived from FDR data. [Reproduced from the Official Report]

On checking in with TWR, the flight crew stated that they were “at holding point A1 for runway 04L, ready for departure” although as previously noted, the aircraft was actually on the bend which links taxiway ‘T’ to taxiway ‘A’ (position 6). In response to their call, the TWR controller cleared them to line up on runway 04L to which two aircraft were on final approach, one with 12 nm to run and another with15 nm to run. The crew read back this clearance correctly and 40 seconds later, they were cleared to “line up and take off from runway 04L”. At this time, the aircraft was on taxiway U (position7). In the absence of a response, the controller repeated the clearance and requested that they make a quick take-off to which he received the response “stand by please” so then asked them to remain at holding point A1. The crew replied that they were on the runway without beginning with the word “negative” to which the controller responded with “OK” and asked them to contact him when they were ready. Soon afterwards, the crew called that they were ready for takeoff and the TWR controller cleared them to line up and make a quick take-off from runway 04L which was read back correctly.

Approximately 20 seconds later (position 8), alerted by a shout from the GND controller who had seen the aircraft accelerating on the taxiway, the TWR controller instructed the aircraft to immediately stop the takeoff as they were on the taxiway. At this point, it had travelled approximately 550 metres from the position where takeoff thrust had been set and had reached a speed “in excess of 85 knots”. The takeoff was rejected as instructed with the speed reaching a recorded maximum of 94 knots before the aircraft began to decelerate. It came to a stop abeam taxiway ‘D’ (position 9) 13 seconds after the instruction to reject had been given after having travelled 922 metres from the position where thrust had been set. Ten minutes later, the flight was again cleared for takeoff which this time occurred in accordance with the clearance given and without further event.

The crew subsequently stated that once they had lined up on what they only later realised was a taxiway, the Captain, who commented that “the lighting had seemed green to him” had asked the First Officer if they were on the runway or the taxiway. After looking outside, “seeing green lighting and believing that taxiways had blue lighting”, the First Officer had “concluded that they were not on a taxiway so had confirmed that they were indeed on the runway”.

The Context for the Error

• A review of exchanges between the flight crew and both the GND and TWR controllers showed that non-standard phraseology had been used by both controllers and the flight crew. It was considered especially significant that the crew had failed to begin their transmission “we are already on the runway” with the word “negative” which would have alerted the controller to the incorrect position of the aircraft given that otherwise he would only have been likely to check that the aircraft was clear of the runway.
• Holding point A1 is indicated by standard-pattern signs on either side of the taxiway and by standard ground markings and runway guard lights with single-direction beams which are aligned so as to be visible to aircraft taxiing towards the holding point.
• All relevant runway and taxiway lighting was functioning correctly at the time of the event.
• Until 1999, Taxiway ‘U’ had been the former runway 04L/22R and was additionally identified as such on the Jeppesen aerodrome chart used by the flight crew. It is slightly longer than the adjacent runway and has a 60 metre-wide paved surface and although ground markings of green and white stripes indicate a reduced width for taxi use, these are not visible at night. This taxiway has the usual green centreline lighting but no edge lighting which is in compliance with aerodrome certification requirements. However, there is no sign at the beginning of taxiway U abeam the beginning of runway 04L, rather such a sign is situated at 250 metres from the beginning of the taxiway. It was noted that the applicable aerodrome certification requirements include a sign which identifies every taxiway “after an intersection” but do not specify any maximum distance from the intersection.
• Portugalia stated that they had assessed the risk of a landing on taxiway U but this “risk mapping” had not considered the risk of a takeoff from this taxiway “because of the lighting that existed”.
• Portugalia’s SOPs at the time of the event were noted to require that Captains were always to act as PF during taxiing and that the initial taxi out should normally be made on one engine in order to reduce fuel consumption. Their ‘Before Takeoff Checklist’ included the explicit warning “to avoid the possibility of departing from the wrong runway, verbally verify the proper runway”.
• The ACC covering Nice had assessed the risk of a landing on taxiway U at Nice but had not considered the risk of a take-off from this taxiway.
• The ACC covering Nice had an A-SMGCS which displayed surface movements at Nice and their identification in real time to the Nice TWR controller. Information from this system included alerts for takeoff or landing on an occupied or closed runway, vehicle incursions, conflict between vehicle and aircraft movement in the opposite direction of an active runway to that in use or on a parallel runway to that in use. Although this system was capable of providing alerting for taxiway takeoffs, this functionality had not been configured for Nice.
• Although only one of the two runways was in use at the time of the event, this was not an exceptional situation and was not considered to have been a relevant part of the event scenario.
• According to the Captain, he had carried out 20 flights to Nice of which “at least 16 had involved a take-off from runway 04L (and) only once when taking off from runway 04L had he taxied via taxiway ‘T’ to taxiway A" which had also been at night, in August 2016, during his first flight acting as PF whilst taxiing. The illustration below is based on the data he submitted. The GND controller observed in his statement that whilst an aircraft could be equally routed via taxiways ‘T’ (or ‘F’) and ‘U’, there were no instructions about this and he usually used the route via taxiway ‘T’ (and ’A’) which meant there were less turns to be made for the crews, resorting the use of taxiway ‘U’ only if another aircraft was being pushed back at Terminal 2 and might interfere with traffic on taxiway ‘T’. He “did not think that a crew could be used to using only taxiway U” for 04L departures.

The Captain’s record of his previous taxi out routes for 04L takeoffs at Nice. [Reproduced from the Official Report]

A total of six Contributory Factors were identified by the Investigation as follows:

• A high workload for the PM during the short taxiing time, due to the start-up of the second engine after the push-back and to the different actions and checks to be performed.
• Insufficient monitoring, checks and confirmation of the position of the aeroplane while taxiing, perhaps because the crew had the habit of taking the same route at this aerodrome which led them to have an erroneous representation of the aeroplane’s position.
• A confirmation bias mechanism which, in the absence of clear signals informing the crew that they were on the taxiway, meant that they gave priority to information reinforcing their erroneous representation of the situation: the change in lighting and the width of the taxiway seemed to be that of a runway. The difference between arriving on a taxiway and arriving on a runway is first and foremost the absence of elements (signs, ground marking at holding point ‘A1’ and runway guard lights, lighting, etc.). Indeed it is easier to note the presence of an unusual element than the absence of something expected.
• The crew’s partial clarification of their position on lining up on taxiway ‘U’ linked to a confusion between the different lighting colours and the pressure to take off quickly.
• The Tower controller focusing on keeping flight traffic flowing rather than on the position of the aeroplane, probably due to the confidence in the crew’s position message, which led to the line-up and take-off clearance being given well before holding point ‘A1’ was reached.
• The use of approximate phraseology which could have allowed the Tower controller to think that the aeroplane was at holding point ‘A1’ although it was in fact lined up on the taxiway.

Safety Action taken as a result of the event whilst the Investigation was in progress was noted to have included but not been limited to the following:

• Portugalia withdrew an SOP which required that an aircraft always left the stand on one engine and replaced this with a recommendation to leave the stand on one engine only when long taxiing times are anticipated and added an item to ‘Check Runway, Confirm Runway’ to the ‘Before Takeoff’ checklist.
• Aéroports de la Côte d’Azur installed centreline lighting on taxiway A and on the part of taxiway ‘T’ situated between taxiways ‘A’ and ‘B’.

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

• that the DGAC DSNA (as the State ANSP) study the advisability of modifying the ground radar at Nice to allow detection of a take-off from a taxiway. [FRAN-2020-001]
• that the DGAC DSNA (as the State ANSP) require the implementation of a procedure for the issue of a takeoff clearance from runway 04L at Nice at night which takes into account the risk of a takeoff being made from taxiway ‘U’. [FRAN-2020-002]

The Final Report was published in English translation on 2 April 2020 following the initial and definitive publication in French published on 26 March 2020. No Safety Recommendations were made.

Related Articles

• Inappropriate use of Runway or Taxiway
• Taxiway Lighting
• Runway Lighting
• Taxiway Surface Markings and Signs
• Non-Standard Phraseology
• Confirmation Bias
• Rejected Take Off
• Runway Awareness and Advisory System (RAAS)