The FAA has approved a process to remove an altitude restriction on 800-series Hawkers equipped with winglets developed by Aviation Partners (API). The agency issued an airworthiness directive in June, requiring operators to comply with API service bulletin SBH-13-001, which limited maximum altitude to 34,000 feet until a fix could be developed. AD 2013-11-16 was “prompted by reports of several instances of severe vibration and wing/aileron oscillations,” according to the FAA.
The Seattle-based company examined the oscillation problem using finite element modeling and flight-tested a solution that involved rebalancing the Hawker’s ailerons.
API has delivered free service kits to operators of winglet-equipped 800-series Hawkers. The kit includes parts and a letter authorizing compliance with the latest API service bulletin–SBH-13-002 Revision A–which was approved as an alternative means of compliance for AD 2013-11-16.