PhD Defense by Andrew Bellocchio

Event Details
  • Date/Time:
    • Friday March 9, 2018 - Saturday March 10, 2018
      8:00 am - 9:59 am
  • Location: Weber Building CoVE Auditorium
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Summary Sentence: A Framework to Enable Rotorcraft Maintenance Free Operating Periods

Full Summary: No summary paragraph submitted.

Andrew Bellocchio
(Advisor: Prof. Schrage]

will defend a doctoral thesis entitled,

A Framework to Enable Rotorcraft Maintenance Free Operating Periods


Friday, March 9 at 8:00 a.m.
Weber Building CoVE Auditorium


For the past 50 years, the paradigm of on-condition rotorcraft maintenance has yielded to random failures and intrusive scheduled maintenance that regularly disrupted flight operations.  The British Ultra-Reliable Aircraft Pilot Program of the late 1990s introduced the paradigm of Maintenance Free Operating Period (MFOP) as a solution.  An MFOP aircraft is a fault tolerant, highly reliable system that minimizes disruptive failures and maintenance for an extended period of operations.  After the MFOP, a single Maintenance Recovery Period (MRP) consolidates repair of accrued faults and inspections to restore an aircraft’s reliability for the next MFOP cycle.  An MFOP strategy provides assurance to the user that flight operations will continue without disruption for the duration of the MFOP at a given success rate.

The U.S. Department of Defense recently adopted MFOP as a maintenance strategy for the next generation of rotorcraft named the Future Vertical Lift (FVL) Family of Systems.  The U.S. military desires uninterrupted flight operations to enable a more expeditionary force that operates from remote, austere bases.  It is thought that a 100-flight hour MFOP at 90% availability will support such deployments; yet, today’s fleet has the system reliability to fly less than ten hours without significant repair at 75% availability.  The challenge presented is to achieve an order of magnitude improvement to meet the FVL target and set the conditions for near-zero maintenance while remaining affordable.

The thesis hypothesizes that statistical based metrics using the mean are insufficient in an MFOP strategy and that metrics such as the MFOP, which include the time history of failure, are as important as the rate of failure.  It will utilize a Discrete Event Simulation to model the MFOP, MRP, and their success rates as operational metrics.  The work will identify which subsystem(s) limit the MFOP of an aircraft and which components drive MRP higher.  It will explore the relationship between MFOP and availability where preventive component renewals occur at discrete multiples of the MRP.  It will test the hypothesis that an operational commander has some control over the MFOP by varying the MRP through an aggressive lifing policy.  Ultimately, the thesis provides a framework to measure the balance between availability, dependability, and maintainability of an MFOP rotorcraft.


  • Prof. Daniel Schrage – School of Aerospace Engineering (advisor)
  • Prof. Dimitri Mavris– School of Aerospace Engineering
  • Dr. Vitali Volovoi –
  • Prof. Rich Melnyk – Dept. of Civil & Mechanical Engineering, US Military Academy
  • Dr. Sylvester Ashok – School of Aerospace Engineering

Additional Information

In Campus Calendar

Graduate Studies

Invited Audience
Faculty/Staff, Public, Graduate students, Undergraduate students
Phd Defense
  • Created By: Tatianna Richardson
  • Workflow Status: Published
  • Created On: Feb 12, 2018 - 1:09pm
  • Last Updated: Feb 12, 2018 - 1:09pm