The US Navy says a “high-pressure schedule” to deliver the first next-generation presidential helicopter unit in fiscal year 2009 is being complicated by airworthiness certification demands and overlapping airframe and system development schedules, but that it is confident of avoiding potential logjams in delivering the Lockheed Martin/AgustaWestland VH-71A.
Navy-specific certification for a number of major structural changes, including a shift to an all-aluminium airframe, may pose the most difficult schedule hazard. The baseline EH101 airframe includes 15% composite structure, but this must be replaced to meet the USN’s crashworthiness standards. However, the certification issue – acknowledged in Lockheed’s proposal documents – is “certainly a factor that we’ve gone into with our eyes open”, says VXX programme manager Doug Isleib.
The navy’s original certification schedule for the VH-71A assumed that none of the EH101’s European certification requirements would be eligible for inclusion in its airworthiness review, but the service has now learned that a “substantial” amount of documentation can be carried over.
Another area of focus is the schedule to complete designs for the airframe and mission payload. Manufacturing requirements dictate that the programme cannot complete the separate design plans simultaneously, and mission systems work will continue after the airframe design team completes its tasks in April.
But Isleib says any risk of the airframe and payload designs proving incompatible should be mitigated by understanding the interfaces between the system elements as design work continues on the mission equipment.
STEPHEN TRIMBLE/WASHINGTON dc
Source: Flight International
