A relatively recent acquisition for me, the IWC Pilot UTC 3251, first released by pre-Richemont IWC in 1998. This particular specimen was produced in 1999, making it one of the last IWC watches with tritium on the dial (as evidenced by the T SWISS MADE T label).
The IWC 3251 is the first Pilot watch from IWC to feature a dual-time complication, which is powered by an ETA movement based on the 2892. Considering that dual-time complications are relatively common on aviation-related watches, it is surprising that it took IWC so long before implementing it on the iconic Pilot watch.
This version of the 3251, the 3251-01, came on a leather strap, with subsequent versions on a bracelet. There were also limited editions in platinum with a violet/purple dial. After Richemont acquired IWC, the UTC became part of the Spitfire family, with stick markers on the '6' and '9' positions.
The IWC Pilot watches at the turn of the century were 36mm in size (Mk XII), and as the UTC was introduced in a 39mm case size, it marked the trend of going larger for the Pilot series. The following year (1999), the 38mm Mk XV was launched. The short lugs accompanying the 39mm case makes the UTC surprisingly compact compared to the modern Mk XVIII/Spitfire.
Fun fact, this Pilot UTC was the first IWC Pilot watch to have a doubly-coated AR crystal! In 2019, more than 20 years since the first UTC was launched, IWC "re-created" the Pilot UTC in a 41mm bronze case, limited to 271 units, with an in-house movement. It does strike me as a little odd, since the properties of bronze are more suitable for a dive watch case.
My Pilot UTC comes on a canvas-embossed leather strap, which was introduced with the Pilot Mk XVIII Miramar edition.