WASHINGTON (Reuters) - The Pentagon on Wednesday said no additional cracks were found on F-35 fighter engines during inspections done after the February 19 incident that has grounded the entire fighter fleet and halted operation of the engines on the ground.

Kyra Hawn, spokeswoman for the F-35 program office, said the investigation into the incident at Eglin Air Force Base in Florida was continuing, with engineers at enginemaker Pratt & Whitney due to break open the affected part for further study on Wednesday.

Pratt, a unit of United Technologies Corp, supplies the engine for the single-engine, single-seat fighter plane, which is built by Lockheed Martin Corp.

Hawn said a separate incident involving temperature control equipment built by Honeywell International Inc has been deemed a "minor test discovery, with no impact to safety of flight or operations."

(Reporting By Andrea Shalal-Esa; Editing by Gerald E. McCormick)