Although I had decided long ago that I would restrict myself to comment on this UK national sport where the facts are disregarded ( either by ignorance or willingly) in favor of the ever popular French bashing , but here we go again ,
The BEA report and the Incident investigation ( in French) are giving the following facts .
1- Due to a technical issue, on the TWR the normal Control position for Runways 09 could not be opened. ( First day or reopening of the North TWR after being closed 2 weeks )
2-The controller had to work for another control position where she did not have visual on the 09 thresholds.
3- The standard configuration that morning was 09L for landings and 09R for take off.
4- She was alone on the position , despite being extremely busy , the Coordinator position supposed to relieve the workload, was not manned that morning .
4- After a missed APP on 09L due to a technical issue an AF requested to land on 09R ( much longer than 09L) which she could not refuse.
5- UA was cleared by APP for ILS 09L and was stabilized on 09L when transferred to tower the controller mistakenly ( lapsus) said clear to land 09 R while she later said she meant 09L.
6- UA replied :" Understand cleared to land 09 Right, side step for 9 Right United 57 »
7-The controller did not acknowledge the transmission but said she did not pick up the 09R reply, and did not associate the word "understand" with a request for confirmation .
8- The side step was performed at 900ft, 2,2 NM out with 09R has a much earlier positioned Runway threshold.
Now the remarks :
The FAA ahs a clear procedure for performing sidesteps, France ( and I suspect EASA) does not have something similar and it is not a common procedure , unlike in the US. .
The term " understand" is used in FAA phraseology while in rest of the world we use the term " Confirm " ( as is ICAO standard phraseology)
Not having readback confirmation from ATC on Final is something usual in the US, but not in Europe.
My own remarks :
If the UA was using the term "understand" to ask a question , the fact of not receiving an answer should not be considered as an approval to continue.
A simple " confirm 09R?" from UA would have eliminated the issue.
If there is something to learn from this incident is to use standard phraseology , especially when flying outside your home country,
Now to the dual language issue that always comes up when an incident is happening in CDG , This one was all in English , so not a factor here. For those here that want to perpetuate this crusade , you should start to fly a bit outside your home country . The vast majority of the world's airspace is controlled bi-lingual , outside of a few tiny Caribbean islands, the whole airspace south of Rio Grande is in Spanish or Portuguese, Canada up North is even partially bi-lingual
3/4 of Africa are bi-lingual, so is Russia and China. Most European countries are too, France of Course Spain , Portugal, etc.. but also Germany for instance on all their airports , Yes you can hear German on Frankfurt Tower for the VFR mid fields crossings or departures below the ILS... Almost all Military ATC is done in National language and operating from dual civil-military's airports
I think aiming at world peace has more chances of success that eliminating national languages from ATC .