Bell Helicopter is working to overcome two recent test flight incidents before moving the $6.3 billion H-1 upgrade programme into a long-delayed operational test phases.
The most serious incident involved a hard landing on a golf course by an AH-1Z Super Cobra, says Kevin Connell, Bell’s H-1 upgrades manager. During a particularly difficult envelope- expansion manoeuvre, the pilot’s control inputs produced an unexpectedly strong response from the flight controls.
The motion caused the rotorhead cuff to break, producing vibrations that produced tailboom loading of about 17g, says Connell. Despite the severe pressures, the tailboom structure survived with only a slight material “wrinkle” as damage. The aircraft, however, has been reassigned to ground tests of rocket-gas ingestion, says Connell.
A second incident has also slowed the UH-1Y programme. The pilot greatly exceeded the aircraft’s angle of attack limit on a manoeuvre, producing a negative pressure effect that sucked a battery door off the airframe.
The operational test and evaluation phase is now running months behind schedule and is due to start in the third quarter.
The USN is now converting the UH-1Y remanufacturing strategy into a new-build programme, with 88 of the 100 planned airframes to start as green aircraft.
Source: Flight International
