PAUL LEWIS / WASHINGTON DC
Addressing safety issues after crash investigations key to resurrecting US Navy/Bell Boeing programme
The US Navy and the Bell Boeing V-22 Osprey Joint Programme Office (JPO) has outlined an iterative roadmap for redesigning and upgrading the troubled tiltrotor, with the initial goal of resuming flight testing of a small number of engineering and manufacturing development (EMD) aircraft by next April.
The JPOsays a block approach has been adopted to resurrect the programme, starting with an EMD configuration that is intended to address the most immediate flight safety issues highlighted by recent crash investigations. This will be followed by a succession of Block A, B and C changes and improvements to the V-22 fleet to address criticism from a high-level review panel that investigated the programme earlier this year.
The US Navy's NAS Patuxent River-based EMD aircraft will be the first V-22s to resume flying and will have upgraded flight control software, due for release in February, and improved warning, cautions and advisories information available to the crew.
There will be recurring inspections of the hydraulics system and wiring to ensure adequate clearance. The most recent fatal crash, in December last year of a US Marine Corps MV-22 at MCAS New River, was blamed on a combination of a hydraulic line failure as a result of chaffing on a wiring bundle and a flight control software fault.
There are two EMD V-22s at Patuxent River and another two modified EMD CV-22s with the US Air Force. The plan calls for the EMD tiltrotors to be supplemented with two or three low-rate initial production (LRIP) MV-22s which are being built at Bell's Amarillo, Texas, plant.
EMD flight testing will concentrate initially on pilot proficiency/currency, aircraft shakedown with checks on the ground, in hover, climb and in aeroplane mode, flight control software evaluation and high rate of descent flight. The latter is intended to address the cause of the fatal July 2000 crash at Marana, Arizona, when a MV-22 entered a vortex ring state as the result of an excessively steep descent.
The eight LRIP tiltrotors at New River will remain grounded and may not fly for another year until they are modified to the planned Block A fleet configuration. This will incorporate redesigned hydraulic lines and wiring routes, along with improved reliability and maintainability. The follow-on Block B will provide enhanced suitability and maintenance accessibility and Block C improved mission capability.
In the meantime, defence undersecretary for acquisition Pete Aldridge has postponed to this month a decision on the V-22's long-term future beyond LRIP. The LRIP work is sustaining production at an economic minimum of 12 tiltrotors a year. Industry is concerned that in the absence of any political commitment to full rate production, the programme is in danger of withering away.
AgustaWestland and Lockheed Martin are to market jointly the European company's three-engineed EH101 medium-lift helicopter to the US Government. Immediate attention is focused on a USAir Force requirement for combat search and rescue machines. Lockheed Martin's Systems Integration business has considerable experience with the EH101 as prime contractor for the UK Royal Navy's Merlin maritime helicopter version of the EH101. AgustaWestland also held talks with Bell and Boeing.Source: Flight International
