What Caused A United 787-10 To Be Cleared For An Occupied Paris Runway?

In July of 2020, a United Airlines 787-10 had a near-miss in Paris when ATC cleared the aircraft to land on an occupied runway. At the time, the runway assigned for landing, 09R, was already occupied by an easyJet A320 on its way to Spain. A year has passed since the incident, and French investigators have released their final 14-page report with their conclusions and probable causes on the potentially disastrous incident.

United 787-10
The aircraft involved was a United Airlines Boeing 787-10 registered as N16009. Photo: Dylan T via Wikimedia Commons 

Findings from French investigators

France’s Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA, French: Bureau d’Enquêtes et d’Analyses pour la sécurité de l’aviation civile) has released its findings a year after the incident occurred.

The report retells the series of events on July 19th, stating that ATC had given the United 787 clearance to land on runway 09R, despite the aircraft being on ILS approach on runway 09L. On that day, landings were assigned to runway 09L while take-offs on runway 09R.

Untied airlines go around
Triggered by a warning from the easyJet A320, the United Airlines performed a go-around and landed safely on the correct runway. Photo: FlightRadar24.com

With this assigned clearance and seemingly wrong instruction, the crew, wishing to dispel doubt on the authorization, read back the landing clearance by adding the specific phrases “Understand” and “Sidestep for 9 right” while also waiting for a possible correction of the clearance by the controller. However, the controller did not check the crew’s readings, and the aircraft continued towards 09R instead of 09L.

According to The Aviation Herald, the BEA report (translated from French) offered the following points as probable causes of the serious incident:

  1. A “mental slip” by the air traffic controller when clearing the 787 to land on an occupied runway. This was made worse with the readback by the 787 crew not being verified.
  2. The traffic management at that moment was mainly on runway 09R (one landing, two departures, two runway crossings)
  3. The controller’s concern with their change of position from Local NorthWest to Local NorthEast
  4. The controller’s lack of practice was connected to the decrease in traffic during the COVID-19 crisis period.
  5. The use of the non-standard expression “Understand” by the flight crew rather than “confirm” which would have attracted more attention from the controller.

A change in controller position caused by a turned-off screen

With regards to the third point and the change in position, the BEA briefly noted that the screen of the Local Northwest Control position in the North Control Tower could not be turned on. This is how the situation was described in the report:

“The controller indicated that she took up her post in the north tower of the airport at 4:30 am on the day of the occurrence, and that she was in the LOC NE position. Usually for the east facing configuration, the LOC NW position is used. The control screen in the LOC NW position was off and appeared, according to the controllers, to be out of order.”

BEA Report LOC NE and NW
Positions of LOC NW and LOC NE for Paris CDG’s North Control Tower. Photo: BEA

The report goes on to say that this was the first day the north tower opened after two weeks of closure, following exclusive use of the south runway pair controlled from the south tower and central tower.

During this period, the screen was turned off by its main switch, which is different from what controllers would do on a daily basis. In fact, the main switch is “located in a place that is not easily accessible to them,” with the report stating that controllers were not aware of this master switch.

With the controller in the NE position, facing the holding points of runway 27L, she did not have direct visual contact with the thresholds of runways 09 from her position in the control tower.

Paris CDG
Paris CDG had undergone some operational adjustments due to the pandemic. Photo: Dmitry Avdeev via Wikimedia Commons


It looks like human error was undoubtedly the most significant factor in this potentially disastrous incident. After all, the situation can be boiled down to the mistake of saying “09R” instead of “09L.”

While the majority of ‘blame’ can be put on the controller, we can see that a number of factors contributed to the situation, putting them in a worse position that increased the likelihood of error.

With these findings released, what are your thoughts on the incident? Let us know by leaving a comment.