The FIA has told Formula 1 teams that they can henceforth mount their rear view mirrors on the halo, as long as they comply with all relevant regulations.
Mirrors have become a talking point this year, with drivers noting that it has become even harder to see anything behind them with the current rear wing regulations, and the likes of Ferrari tailoring their design more than ever before for aerodynamic gains.
Some teams may now regard mounting mirrors on the halo as a chance to find further aerodynamic benefit.
After enquiries on the subject, the FIA's single-seater technical boss Nikolas Tombazis has clarified the governing body's position and given the go-ahead for teams to follow that route.
However, they will still have to meet all current regulations related to mirrors, including those that specify the theoretical "box" within which they have to be located, their minimum 150mm x 50mm dimensions, and the ability to meet a rear vision test conducted by the FIA, in which a driver has to read letter or number boards placed behind the car.
Mirrors will also have to comply with the new rule on laminate of any parts that are within 20mm of the halo structure, which was written to cover aerodynamic fairings.
In a Technical Directive the FIA has told teams that the onus is on them to prove that the mountings are secure: "We expect that you will be able to satisfy us that the installation is sufficiently rigid to ensure that the mirror does not vibrate too much, which would limit driver visibility."
In addition, mirrors cannot be mounted both on the halo and the chassis, because such an arrangement would make it harder to remove the halo.
Tombazis wrote: "We will not accept a dual mirror mounting (halo + traditional survival cell), as this could cause delays in the event a rescue team had to remove the halo following an accident."
The FIA also pointed out that teams will not be able to fit working cameras in halo-mounted mirrors, and that this could become an issue should FOM request that a particular car run such cameras.
"We will not accept a cable or connectors to run through the halo fairing, hence in the rare case when a team is asked to mount cameras in the mirrors (position 1 of Drawing 6 of the Technical Regulations), that team would have to resort in using a mirror installation on the chassis or side pod."