Cengiz Topel Naval Air Station (Topel Airport / Cengiz Topel Havalimanı)

Cengiz Topel Naval Air Station is a joint military and civil airport located east of İzmit in Kocaeli Province, Turkey. It is situated between the E80/D.100 highway and the O-4 motorway, west of Lake Sapanca. Originally built as a Turkish Air Force facility, the installation transitioned to joint air force and navy use in May 1973 when the navy's first rotorcraft unit relocated there from Ankara. On July 14, 1976, control of the base was transferred to the Turkish Navy Command. The Naval Air Station Command was formally established on August 4, 1976. The station was assigned to NATO on October 28, 1981, and later opened to public civil air traffic in 2011.

The facility is operated by Turkish Naval Aviation and serves as the home of the Turkish Naval Aviation Command. Resident flying units include the 301st Naval Air Squadron and the 351st Naval Helicopter Squadron. The 301st Squadron operates fixed-wing aircraft, including CN-235-100M maritime patrol aircraft, ATR-72/600 aircraft, and TB-20 trainers. Historically, upon its relocation to the base in 1976, the 301st Squadron operated S-2 Tracker maritime patrol and anti-submarine warfare aircraft. The 351st Squadron operates the station's rotorcraft. To support the air station's helicopter operations, additional helipads in Istanbul and Çanakkale were established in 1983.