E190 / D328, Basel Mulhouse France, 2016
E190 / D328, Basel Mulhouse France, 2016
On 7 March 2016, an Embraer 190 entered the departure runway at an intersection contrary to an ATC instruction to remain clear after neither a trainee controller nor their supervisor noticed the completely incorrect readback. An aircraft taking off in the opposite direction was able to rotate and fly over it before either controller noticed the conflict. The Investigation was told that the crew of the incursion aircraft had only looked towards the left before lining up and concluded that the event had highlighted the weakness of safety barriers based solely on the communications and vigilance of pilots and controllers.
On 7 March 2016, an Embraer 190 (PH-EXB) being operated by KLM Cityhopper on a scheduled international passenger flight from Basel Mulhouse to Amsterdam as KLM1986 entered the departure runway in normal daylight ground visibility just as a Dornier 328 (HB-AEO) being operated by SKYWork on a domestic passenger flight from Basel Mulhouse to Bern as SRK51R was taking off in the opposite direction. ATC only recognised the conflict when it was too late to resolve it by further instructions but fortunately, the other aircraft was just able to overfly the incursion aircraft after a late sighting of it.
An Investigation was carried out by the BEA France. Recorded flight data was available from both the aircraft involved but relevant recorded voice data had been overwritten. A record of relevant ATC communications was available and interviews with the pilots involved were conducted. All ATC communications were conducted in English. Pilot experience information was not recorded but it was noted that although the E190 First Officer had been designated as PF, the Captain was responsible for taxiing the aircraft due to the absence of a steering tiller at the First Officer position. The TWR position was occupied by an experienced controller who was being supervised by an OJTI in order to qualify at Basel Mulhouse after transferring as an experienced controller and OJTI from Nice.
Prior to start up, the E190 crew had requested runway 33 for departure having noted from the ATIS that the surface wind was almost calm and that the runway in use was 15 with the short runway 26 also available for takeoff. They were given a departure clearance based on a runway 15 departure and advised that they would be told later if their runway 33 departure request could be met. When they requested push back, this was approved and the controller advised that a runway 33 departure would be possible and issued a new departure clearance. Meanwhile, the Dornier 328 had already pushed back and, on calling for clearance to taxi for runway 15, (point 1 on the illustration below) requested “a short cut to the left” and was cleared to taxi to runway 15 via the parallel taxiway ‘BRAVO’. Departure from intersection ‘GOLF’ was subsequently (at Point 3) requested and approved. On completion of this exchange, the E190 (at Point 2) requested taxi clearance and having accepted ATCs offer of a runway 33 departure from intersection ‘DELTA’, was cleared to the holding point there.
The D328 was transferred from GND to TWR and on checking in (at Point 4) the crew advised that they would be ready on reaching ‘GOLF’ and were cleared for takeoff. About half a minute later (at Point 6), the E190 was transferred from GND to TWR and reminded in non-standard phraseology to “maintain DELTA” which was read back correctly. On checking in with TWR (Point 7) the E190 crew advised that they were ready for takeoff. TWR responded (Point 8) by instructing them to “hold short of runway 33 DELTA” and the crew immediately read back (Point 9) “Line up and wait runway 33 DELTA”. This completely incorrect readback was not noticed by the TWR controller who, on completing his transmission, had looked away and conducted a brief exchange with another departing aircraft and did not notice that the E190 had entered the runway. The supervising OJTI had also looked away and was similarly unaware of the incursion. The E190 Captain subsequently stated that he had been under the impression that runway 33 had become the runway in use and had therefore only looked to the left before entering the runway - it was subsequently established that had he looked right, the approaching D328 would have been clearly visible. The crew of the D328, which had already commenced its takeoff from runway 15 intersection GOLF, which gave them 1470 metres to go until reaching intersection DELTA, reported that they had first seen the E190 entering the runway about 300 metres ahead as they neared V1 and were able to get airborne and pass safely over it. They stated that at no time had they considered rejecting their takeoff because they believed this would have greatly increased the risk of collision. Six seconds after the E190 began to taxi onto the runway, the controller saw it (see the relative positions of the two aircraft - Point 10) and transmitted “KLM 1986 maintain position, stop”. This was followed almost immediately by the SRK51crew transmitting “we are airborne, we are airborne, don’t worry” (see the relative positions of the two aircraft - Point 11) before they overflew it. The minimum vertical separation between the two aircraft as the D328 passed over the E190 was subsequently found to have been 380 feet.
The Investigation noted that:
- The E190 crew had the opportunity to recognise that the D328 was also likely to depart at about the same time as they were using the opposite takeoff direction as both aircraft were working GND until the D328 was transferred to TWR. However, the E190 crew did not change to TWR until after the D328 had been given a takeoff clearance on the TWR frequency prior to entering the runway. The E190 flight crew subsequently stated that the Captain had invited an off duty cabin attendant to occupy the flight deck supernumerary seat and that having been provided with a headset, this person had then spoken on the intercom during the taxi out which had constituted a distraction.
- The KLM Cityhopper OM included a section on the “sterile flight deck” which included a requirement to “limit intra-flight deck communication to the necessary communication for the operation of the aeroplane and the proper conduct of duties’’.
- The arrangements for designating and using the available runways in the local ATC Operations Manual stated that by day, "runway 15 is preferred for landing. Runway 26 is preferred for take-offs (with) runway 33 used only if the tailwind component on runway 15 is greater than 5 knots or at the pilot's request, if traffic permits". This Manual did not contain any specific instruction in respect of allowing opposite direction takeoffs when runway 15 is in use. It was noted that there had been around ten times as many takeoffs on the main runway 15/33 as on the secondary runway 08/26 with the majority of these - in excess of 80% - made in the 15 direction.
- Stop bars were installed at all main taxiway intersections with the main runway but except for those at the two runway thresholds, these were not individually controllable and so were only used when LVPs were in force.
- ATC had a movement display system which provided a synthetic colour image of aircraft and vehicles on the movement area but this didn’t include runway incursion alerting or easy identification of moving vehicles and controllers stated that it was not sufficiently accurate to allow detection of precise aircraft positions.
- The use of “maintain” in place of the ICAO standard “hold short” when the GND controller transmitted to the E190 crew on taxiway DELTA just before passing them over to TWR was a notified French difference. The subsequent “hold short” instructions given by the TWR controller were in accordance with the ICAO standard.
- The KLM Cityhopper aircraft was fitted with two identical Digital Voice Data Recorders (DVDR). Only data from DVDR1 was made available to the Investigation and neither it nor DVDR2 contained relevant recorded voice data. KLM Cityhopper discovered that their procedures for ensuring the preservation of recorded data were not fit for purpose because the flight crew procedure was to de-activate DVDR2 whilst the procedure for maintenance personnel required the preservation of data on DVDR1. In this case, the crew verbally requested maintenance personnel to preserve DFDR2 after they arrived in Amsterdam but failed to make a corresponding entry in the aircraft Technical Log or de-activate the unit. In addition, it was found that before taking any action in respect of a DVDR, maintenance personnel were required to get approval from Maintenance Control and be issued with a task instruction and as a result, both DVDRs continued to record. Only when Maintenance Control later learned that the Dutch Safety Board had been requested by the BEA to ensure the recorded data was preserved was any action taken, by which time no relevant voice data remained.
It was determined that the runway incursion resulted from an incorrect understanding of the ATC instruction by the crew of the E190 and the ATC not detecting the read-back error. A partial visual check by the crew, prior to entering the runway, and partial ATC surveillance did not prevent the incursion.
Four Potential Contributory Factors were also identified:
- an inaccurate perception of the crew regarding the runway in use
- time pressure and distraction in the cockpit
- use of a short taxiway to the runway which left little time for the crew to build an appropriate perception of the actual situation
- simultaneous management by the ATC of a VFR flight and another IFR flight leaving from runway 33.
Overall, it was considered that this Serious Incident highlighted the weakness of safety barriers when they are based solely on crew/controller communications and the vigilance of crews and controllers. It also demonstrated that these safety barriers are not always a guarantee against the risk of runway incursion, a problem which is greater at airports such as Basel-Mulhouse where the configuration allows takeoffs in both directions from short intermediate taxiways.
It was also considered that the following could have contributed to the prevention of this event:
- implementation of specific phraseology to reduce the risk of confusion and to inform crews of the reasons for holding short. When SERA ‘C’ entered into force in October 2017, this phraseology was generalised to all aerodromes;
- implementation of a system for monitoring surface movements and automatic detection of runway incursions (A-SMGCS Level 2). Implementation at Basel-Mulhouse is planned later in 2018.
Safety Action taken as a result of the Investigation was noted as having included, but not been limited to, the following:
- Eleven days after the occurrence a directive was issued prohibiting takeoffs in the opposite direction to the runway in use unless the aircraft involved used the full length of the runway.
- An Instruction was subsequently issued to controllers to cease mention of the runway in any clearances to hold short of holding points.
The Final Report was issued on 28 March 2018. No Safety Recommendations were made.