From Halopedia, the Halo wiki
Sensor vanes are a component on the starships of the Covenant. They are used by these ships as sensor equipment. The means through which this is achieved is unknown, though it is likely that they serve as a part of the ships' hyperscanner arrays.
To date, sensor vanes have mostly been observed on the Covenant cruiser classes - with the layouts and design varying between various design pattern classifications. Despite this, while sensor vane layouts can be used to differentiate the various design schemes, they are not always a reliable indicator. Ships observed with sensor vanes installed include the;
- Ket-pattern battlecruiser
- Maugen-pattern armored cruiser
- Rothen-pattern fireship
- Varric-pattern heavy cruiser
- Useumru-pattern voidpiercer
- Zanar-pattern light cruiser - the Zanar's sensor vanes can sometimes exhibit mutations during the ship's manufacturing process which let them appear friendly to Forerunner Sentinels.
- Halo Waypoint, Canon Fodder - Calm in the Storm: "No, although the sensor vane layout is often a way of helping to differentiate between different patterns. For example, if you look closely most of the battlecruisers you see in Halo 3 are actually different from than the Ket-pattern Truth and Reconciliation described in Halo: Warfleet (pp. 62-63), despite their similar fin arrangement." - Kenneth Peters (Retrieved on Aug 4, 2021) [local archive] [external archive]
- Halo: Warfleet, page 73