What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-5) As pilot was completing his start procedure, maintenance personnel stationed near-by saw flames erupt from the aft fuselage (tailcone) with fluid also on fire running from the lower aft fuselage. Pilot shut down engine and safely climbed from the cockpit. The fire was quickly extinguished by the maintenance personnel and also sprayed as a precaution by airport crash-rescue truck. Investigation revealed that the right exhaust nozzle actuator hydraulic hose had ruptured(part of the after-burner system), causing the leaking hydraulic fluid to ignite in the engine exhaust tailcone. Damage to the aircraft was limited to the interior and exterior skins of the tailcone assembly. The remaining F-35 aircraft the company operates will have these hoses inspected as a precaution.
As the FAA filed it
(-5) AS PILOT WAS COMPLETING HIS START PROCEDURE, MAINTENANCE PERSONNEL STATIONED NEAR-BY SAW FLAMES ERUPT FROM THE AFT FUSELAGE (TAILCONE) WITH FLUID ALSO ON FIRE RUNNING FROM THE LOWER AFT FUSELAGE. PILOT SHUT DOWN ENGINE AND SAFELY CLIMBED FROM THE COCKPIT. THE FIRE WAS QUICKLY EXTINGUISHED BY THE MAINTENANCE PERSONNEL AND ALSO SPRAYED AS A PRECAUTION BY AIRPORT CRASH-RESCUE TRUCK. INVESTIGATION REVEALED THAT THE RIGHT EXHAUST NOZZLE ACTUATOR HYDRAULIC HOSE HAD RUPTURED(PART OF THE AFTER-BURNER SYSTEM), CAUSING THE LEAKING HYDRAULIC FLUID TO IGNITE IN THE ENGINE EXHAUST TAILCONE. DAMAGE TO THE AIRCRAFT WAS LIMITED TO THE INTERIOR AND EXTERIOR SKINS OF THE TAILCONE ASSEMBLY. THE REMAINING F-35 AIRCRAFT THE COMPANY OPERATES WILL HAVE THESE HOSES INSPECTED AS A PRECAUTION.