Operational Loads Monitoring for Business Jet Aircraft

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Operational Loads Monitoring for Business Jet
Aircraft

• Doug Marshall
• CGAR Annual Meeting

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Introduction

• The aviation industry has long been concerned
  with many operational and safety variables, which
  can be analyzed and used to assess aircraft
  design and structure of airframes.
• Usage data from typical operations can offer
  insights into the safety, aerodynamics, aircraft
  performance, and useful life spans of those
  platforms.

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Pilot error? Ground crew mistake? Fatigue failure?
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FOQA Programs

• For commercial airliners and military aircraft,
  programs such as Flight Operations Quality
  Assurance have been implemented to monitor many
  aspects of pilot and aircraft performance.
• Similar programs for assessing airframe lives are
  not widely available in the general aviation
  community, if they exist at all.

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Prior Collected Data

• To date the FAA has collected considerable
  amounts of typical in-service usage for airplane
  models
• B-737/400
• MD-82
• B-767/200
• A-320
• B-747/400
• B-777/200
• F27/28
• CRJ/100
• BE-1900D
• Cessna-172

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Prior Collected Data

• A number of airplanes used in the firefighting
  and agricultural roles.
• Plans are in place to acquire service data from
  the A-340/300/600, A-380 and ERJ-135/145 models.
• In almost all cases, the usage information is
  acquired via the download of data from the
  airplanes Digital Flight Data Recorders (DFDR).
• Missing from the list above are the Business Jet
  airplanes.

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Benefits

• The FAA uses these data to
• Assess/reassess the technical basis for its
  regulations and advisory circulars.
• Special studies can/have be/been conducted to
  prevent future surprises. (B787, A380
  composites)

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Benefits

• Aircraft manufacturers use these data to
• Update the fatigue and damage tolerance loads on
  the current fleet, and
• Provide accurate fatigue and damage tolerance
  loads for both repair of current airframes and
  design of new airframes.

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Benefits

• The airlines benefit from these data as well for
  improved maintenance scheduling and they can
  conduct trade studies of operational procedures.
• The data can also provide insight into future
  service problems.
• Finally, the general public benefits from the
  additional level of safety attained from the
  knowledge of commercial airplane measured
  operational service usage.

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Benefits

• The data provided by digital flight recorders are
  very useful and provide unique information on the
  performance of that particular aircraft.
• For the business jet operators, it is of even
  greater importance to acquire and analyze the
  data for a wide variety of types and models that
  are being introduced to the fleet already
  equipped with digital flight recorders.

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Data Acquisition

• Systematic acquisition of data from these
  aircraft that are delivered equipped with sensors
  and other performance monitoring equipment.
• Installation of DFDRs or QARs.

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Data Acquisition

• Aircraft that will be so equipped for purposes of
  this study will enable the researchers to
  quantify and analyze the stresses over the
  lifespan of these airframes as they are flown at
  high altitudes, airspeeds and numbers of cycles.

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Data Acquisition

• The collected data will be used to supplement the
  existing database of transport aircraft usage so
  as to continuously validate and update flight and
  landing load airworthiness certification
  standards on the basis of actual measured usage.

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Research Design  

• Under the guidance of the Federal Aviation
  administration and with the help and cooperation
  of aircraft owners and operators, the statistical
  data characterizing the operations of business
  jets will be acquired by downloading and
  analyzing raw data from digital flight data
  recorders over fixed periods of time.
• Some pilot sensitivity issues.

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Research Design  

• Some newer business jet models are entering
  service in the U.S. equipped with DFDRs, making
  them prime candidates for inclusion in the FAAs
  research efforts.
• The flight parameters recorded are listed in CFR
  Part121 Appendix B or Appendix M, depending on
  the airplanes date of manufacture.

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Research Design  

• Business jet owners/operators were approached to
  volunteer their aircraft for inclusion in this
  study, and appropriate nondisclosure agreements
  were offered between the owners and the
  universities responsible for collecting and
  analyzing the data.
• The operator would have the right to review all
  results.  
• Data can be desensitized if necessary

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Research Goals

• The collected data is expected to reveal critical
  information about the external loads to which
  aircraft components are subjected during normal
  flight operations.

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Research Goals

• The resulting data base will be utilized to
  analyze aircraft usage patterns and to update
  flight and landing load airworthiness
  certification standards based upon actual
  measured values.
• It is anticipated that data from a minimum of
  3,000-5,000 flights per aircraft type will be
  necessary to secure meaningful results.

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Scope of Study

• Three different aircraft types in three size
  categories will be selected for study.
• The first aircraft with QARs installed by the
  researcher is the Bombardier Global Express.
• Industry partner operates two.

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Finding a Partner

• Desired an industry partner owner/operator
  whose fleet is already equipped with DFDRs or
  similar devices so that there would be no need
  for installation of equipment or the cost of
  acquiring Supplemental Type Certificates.

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Pete Sparacino
Mike Edwards
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Challenges

• Lack of cooperation
• Flight Safety Foundation involved-FOQA
• Major fractional almost went along
• We dont fly aging aircraft
• Most business jets older than about 5 years are
  not equipped with DFDRs or QARs
• Had to purchase QARs for installation
• Will sell them to the operator at end of study
  if they are not removed

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UNDs Tasks

• Acquisition of operational usage data in a format
  selected by University of Dayton Research
  Institute (UDRI) and assisting UDRI with the
  statistical analysis.
• Secure access to the aircraft selected for the
  study
• Ensure the integrity of the data acquisition
  process
• Identifying and preserving the data, maintaining
  confidentiality, liaison with the owner/operators
  
• Negotiating and administering any payments to the
  owner/operators that may become necessary to
  carry out the study.

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UNDs Task

• UDRI will take the lead in the data reduction and
  the statistical analysis
• Utilize graduate students as much as possible to
  perform all of these tasks.

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Expected Results

• This investigation will focus on providing
  typical usage data for use in determining the
  lifespan of various business jets.
• Determine the current status of airframes in
  service for the past 5, 10, 15 and 20 years.
• Are they being flown the way they were designed?
•  

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Data Collection

• The aircraft usage data includes statistics
  on
• Aircraft weights
• Flight distances
• Altitudes
• Speeds
• Flight attitudes

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Data Collection

• Flight loads data include statistical
  information on
• Gust and maneuver load factors
• Derived gust velocities
• Ground-air-ground cycles.

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Data Collection

• Ground loads data include statistics on
• Lateral, longitudinal, and vertical load factors
  during different ground operational phases.

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Data Collection

• Systems operational data include statistics on
  flap usage, thrust reverser usage, and engine fan
  speed.

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Parameter Sampling Rate Parameter Sampling Rate
Vertical acceleration 10 per second Mach number 1 per second
Lateral acceleration 4 per second Pressure altitude 1 per second
Longitudinal acceleration 4 per second Gross weight 1 per second
Aileron position 4 right and 4 left (2 inboard and 2 outboard) 2 per second each Fuel quantity 1 per second
Elevator position 4 right and 4 left (2 inboard and 2 outboard) 2 per second each Bank angle 2 per second
Rudder position - upper and lower 1 per second Pitch angle 4 per second
Horizontal stabilizer position 1 per second Magnetic heading 1 per second
Flap position 2 right and 2 left (1 inboard and 1 outboard) 1 per second each True heading 1 per second
Spoiler/speed brake position - 4 and 12 1 per second each Latitude 1 per second
Slats position right and left 1 per second each Longitude 1 per second
N1 Engine - right and left 1 per second each Total air temperature 1 per second
N2 Engine - right and left 1 per second each Radio altitude 1 per second
Thrust reverser status right and left engine 1 per second each Autopilot - left, center, right 1 per second each
Exhaust gas temperature - 2 right and 2 left 1 per second each Ground speed 1 per second
Squat switch - main, left 5 per second Inertial vertical velocity 2 per second
Landing gear down and locked - main gear (right and left), nose gear 1 per second each Glide slope - left, center, right 1 per second
Computer airspeed 1 per second Wind speed (not available for all flights) 1 per second
True airspeed 1 per second Wind direction (not available for all flights) 1 per second
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Quick Access Recorder
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The Final Product (we hope)

• Boeing 777 Loads Report

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Past Studies

• Some interesting data
• Suggested that some aircraft are overdesigned
• Pilots dont fly large aircraft quite as hard as
  the designers anticipated
• Identify other unexpected phenomena
• Cleveland Airport
• Side loading

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Next Phase

• Agriculture Aircraft
• UASs?

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Questions?