Acquisition: V-22 Osprey Hydraulic System [report]

Shelton R. Young, Donald A. Bloomer, Richard A. Brown, David A. Palmer, Michael J. Roark
2002 unpublished
Subject Terms Report Classification unclassified Classification of this page unclassified Classification of Abstract unclassified Limitation of Abstract UU Number of Pages Executive Summary Who Should Read This Report and Why? DoD civilian and military personnel involved with the design and development of new systems will find these issues in reliability data helpful in improving their own areas of product development. Background. The V-22 Osprey Joint Advanced Vertical Aircraft (the V-22) is a
more » ... aft (the V-22) is a tiltrotor, vertical takeoff and landing aircraft, which was developed to fulfill multi-Service operational requirements. The V-22 design incorporates advanced technologies in composite materials, digital avionics, fly-by-wire controls, and survivability. It operates as a helicopter for takeoffs and landings and, once airborne, converts to a turboprop aircraft for distance flight. That conversion capability is accomplished through the tilting or rotation of a nacelle mounted at the end of each wing. Each nacelle is equipped with an engine and transmission that drives a rotor with a diameter of 38 feet. The V-22 hydraulic system, which comprises three independent subsystems, provides hydraulic power to the V-22 rotor system controls and control surfaces. Results. Additional oversight and maintenance training measures were needed to improve the reliability of the hydraulic system for the V-22 Osprey. The V-22 entered the Low-Rate Initial Production phase in 1997 with a hydraulic system that performed at reliability rates significantly lower than predicted in the design process. During the Engineering and Manufacturing Development phase, the system achieved no better than 38.2 percent of the predicted reliability rate. The V-22 was produced with a less-thanoptimal hydraulic system because the V-22 Program Manager (PMA-275) did not exercise sufficient oversight of the hydraulic system's design: PMA-275 did not specifically monitor the reliability rates of the hydraulic system's performance. In addition to previously mandated design changes, other actions are needed to ensure sufficient management focus on the V-22 hydraulic system's performance and maintenance. A program to monitor the V-22 hydraulic system's performance, especially component reliability rates, on a continual basis will improve the reliability of the hydraulic systems. Also, Bell Helicopter Textron, Inc., should amend course materials for the V-22 maintenance course to include the unique characteristics and hazards of the titanium hydraulic lines. Similarly, the Technical Study Guide Program for Marine Medium Tiltrotor Training Squadron 204 should be amended to expand the discussion of titanium hydraulic lines. (See the Finding section for the detailed recommendations.) Management Comments. The Assistant Secretary of the Navy (Research, Development, and Acquisition) concurred with the recommendations. The Assistant Secretary stated that new hydraulic system reliability predictions were established and a dedicated team was established to monitor actual performance. The Navy was also ii updating its Technical Study guide program to emphasize the unique characteristics and considerations regarding conducting maintenance actions in the vicinity of titanium hydraulic lines. See the Finding section of this report for a summary of management comments and the Management Comments section for the complete text. Management Initiatives. After a fatal accident in December 2000, the V-22 was grounded and PMA-275 began several initiatives, including the establishment of the Line Clearance Integrated Product Team and the Senior Hydraulic System Review Team (the Senior Hydraulic Team), to identify and correct the hydraulic system challenges facing the V-22.
doi:10.21236/ada403472 fatcat:f7pqrnkolfbtxk72dd6toeupby