PILOT-class Mjolnir

The Pilot helmet is a UNSC Air Force pilot helmet adapted for use with all UNSC armor systems, including the MJOLNIR Powered Assault Armor. It entered service in the UNSC Air Force in 2541. It has an appearance similar to the EVA and SPI helmets.

It is an unlockable helmet in Halo: Reach and costs 90000 cR.

"Haunted" Helmet
The Haunted Helmet is a variant of the Pilot helmet which is visorless and has a skull where the face should be. This helmet can be bought for 1 cR, but only after obtaining every other purchasable helmet base. You need to have earned roughly 1400000 cR to purchase every base helmet. The rank in which you need to be is still unknown due to the rank cap Bungie has enforced. Another theory towards unlocking the Haunted permutation of the Pilot helmet involves Halloween, as the description is, "Happy Friggin' Halloween!"