Fleet Issue Collaboration; Improving Safety, Operational Cost and Reliability Through The Sharing

of Aircraft Operational Data

Grant Johnson

Airframe Resolution LLC

NBAA 2013 Business Aviation Convention & Exhibition | 22 Oct 2013

Contact info: Grant@AirframeResolution.com (858) 380-4340

www.AirframeResolution.com

Grant Johnson’s Bio • President of Airframe Resolution and has more that 17 years of

aerospace engineering and aircraft maintenance experience • Served in the Canadian Air Force and has held engineering positions

at airframe manufacturers and tier 1 suppliers • Gained expertise in aircraft design, modification, overhaul, repair

and certification • Extensive understanding of structural fleet problems with business

jets from supporting the western hemisphere Falcon fleet of over 1200 aircraft as well as repair support for over 450 airlines world wide

• Contributed to repair development on the Boeing 787-9 & Airbus A350-XWB as well as virtually all other commercial aircraft types flying today

About Airframe Resolution • Global leader in the evaluation and technical support

of business jets • Offer several cost reduction and quality improvement

programs for new production and in-service aircraft • Contributed to companies savings millions of dollars in

aircraft cost reductions • Solid concession assessments for production defects

that affect in-service repairability and dispatch reliability

• Production defect oversight provides your VIPs the highest safety and reliability

Problem

• Business Jet owners’ typical small fleet do not provide a large enough sample size to gain sufficient reliability and fleet maintenance data

• Difficult to interpret trends

Fleet Size Comparison

• Typical Airline Fleet: 20-500+ A/C

• Business Jet Fleet

Falcon 900: 500+

Gulfstream V: 480+

Global 5000: 500+

Presentation Overview Collaboration of lessons learned is vital

– Production defects – In-service issues and opportunities – Resolution process

Benefits include: 1. Compiling industry operational best practices and solutions 2. Share aircraft reliability data 3. Leverage OEMs and suppliers to seek fleet-wide solutions 4. Provide a wealth of experience to aid in maintenance planning

and aircraft operations

Networking Approach

• Major Airlines like Delta and American are fierce competitors but they collaborate when it comes to safety & reliability

Why aren’t you?

Reliability

Definition

• The probability that an assembly or part will function properly in the operating environment for the expressed service life

Repairability

Definition

• Ability of damaged or failed equipment, structure or system to be restored to acceptable operating condition within a specified period (repair time).

Commercial Airlines

• Airlines typically have onsite reps at Boeing and Airbus to oversee production defects (MRB)

• Engineering specialists are typically assigned specific ATA chapters to oversee during production and then are continued while in-service

Aircraft Quality Assurance

• Do not assume that there are any shortcomings in the quality assurance system of the manufacturer

• Pursue the same goal of attaining the very best production quality and hence maximizing the safety and reliability of the aircraft in operation

Material Review Board (MRB)

• MRB is the process where non-conformities to the aircraft design are addressed during manufacturing and production assembly

• How these nonconformities are addressed can have a significant impact on an aircraft’s operating cost and reliability

Typical MRB Activities

Intent of MRB

• Fit, form & function

• Conformance to certification basis

(Type Certificate)

MRB Costs You $$$

• The problem with MRB repairs is the loss of future repairability during in-service operation

• Limited future repair options means eventual part replacement

• Defects can affect maintenance manual tasks and can also modify aircraft wiring manuals with splices and repairs

Typical MRB Considerations

• Structural loads • Flight loads • Vibrations • Aerodynamic performance • Thermal loads • Dissimilar metals - corrosion • Surface treatments • Lightening protection • Systems interface

MRB Typical Metallic Repairs

• Oversized fasteners from misdrilled holes

• Surface damage treatments

• Edge damage treatments

• Bushing

• Limited welding (high temp parts)

MRB Typical Composite Repairs

Damage caused by delaminations, disbonds, impacts and misdrilling of holes

• Wet layup repair

• Prepreg repair

• Resin internal injection

• Resin surface application

• Core replacement

• Potting (filling core with adhesive)

Case study 1: Just a Few Misdrilled Holes

• Production defect: Misdrilled countersink holes on fuselage skin

• MRB fix - Oversized fasteners

• Future in-service problem – Dent on skin. No repair with fastener countersink hole that are knife edged greater than 67%

• Final result: Skin replacement = $$$$

Fatigue Prone – Unacceptable Acceptable

Case study 2 – Composite Surface Irregularities

• Production defect: Poor cosmetic exterior surface of a composite flight control

• MRB fix: Apply thick bondo primer and sand smooth to improve appearance

• Future in-service problem: Two lightning strikes back to back in two months on the component caused significant damage

• Final result: Increased paint thickness affected the embedded lightening protection by limiting electrical conductivity – Increased the extent of structural damage – Two weeks at an MRO each time at 85K per visit - $$$$

Case Study 3 - Existing MRB Repair

• Production defect: Delamination on composite radome found during production NDT

• MRB fix: Composite scarf prepreg repair

• Future in-service problem: Impact from ground handling in close proximity to MRB repair. SRM repair specifies minimum separation distance requirement; therefore, not permitted

• Final Result: Send unit to supplier for overhaul - $$$$

Case Study 4 – Small Scratch on Slat Leading Edge

• Production defect : Scratch on Clad surface of the part

• MRB fix: Blend out scratch until smooth and polish until blemish is removed

• Future in-service problem: Clad is a thin, pure aluminum protective coating that covers corrosion-susceptible alloyed aluminum like 2024

• Result: Ongoing local corrosion for the life of the part -$$$$ Clad coating

Alloyed Aluminum

Case Study 5 – Part Hole Pattern is Slightly Off

• Production defect: Supplier made part with incorrect offset hole pattern

• MRB fix: Since the assembly is a long lead item at 16 weeks, “Use as is” and match drill in place

• Future in-service problem: Worn out part is found during heavy maintenance check requiring part replacement

– New part has correct hole pattern and doesn’t fit

• Result: Major delay of return to service - $$$$

Case study 6 – MLG Axial Bore Gouged

• Production defect: Landing gear axial bore (trunnion) gouged during assembly

• MRB fix: Increase bore size to remove damage

• Future in-service problem: Deep corrosion in trunnion requiring rebore to remove it. – Limited material remaining for reboring

– Typically one - two rebore repair operations permitted

• Result: Major in-service cost impact - $$$$$$$

Production Concerns

• Configuration management

– Engineering changes

• Performance

– Weight Validation

– Step & Gap

Acceptance Flight Tests

Test flights:

• Green aircraft from final assembly plant

• Finalized aircraft from completion center

Opportunity to collect and share data about the A/C and systems performance

Benefit: Rework aircraft problems prior to delivery

In-Service Issues

• Fatigue prone areas (cracking)

– Very common with elevated temperature parts

• 900⁰F bleed air causes thermal expansion

• Operation can induce further problems

• Corrosion prone areas

– Operating environments have a significant role in the life of the aircraft

In-Service Issues

• Wear

• Vibration

• Interface problems

• Systems – Engines

– Avionics

– Electrical power

– Hydraulic system

In-Service Issues

• Material obsolescence

– Parts no longer manufactured

– Consumables: Banned chemicals

• http://echa.europa.eu/web/guest/regulations/reach

In-Service Issues

• Service bulletins(SB)/Airworthiness Directives (AD) incorporation

– Difficulties

– Recommended changes to planning

– Alternate Means Of Compliance (AMOC)

In-Service Issues

• Improved maintenance procedures – Ease of access – Improved tool/fixture options – Tool sharing – Updates/fixes to manuals – Troubleshooting and problem solving – Arrange planning of maintenance tasks for efficiencies

or lead time

• Drive allowable damage limit (ADL) & repairs to common problems -- FREE! --

In-Service Issues – Bad fuel

• Wing box & fuel tank corrosion from microbiological organisms

• Airlines don’t have the significant threat because a typical 747 flies 16 hours a day

• Business jets are prone to this problem due to low volume of flying

Corrosion Control Study

• Gov’t completed a study where they added desiccant bags inside their business jet fleet when not in use

• Goal was to determine if it was possible to reduce moisture and therefore minimize the onset of internal airframe corrosion

• Study showed it was statistically beneficial in slowing corrosion and also increased the avionics reliability and service length

Fleet Reliability Metrics

• Statistical analysis of multiple user’s maintenance data

• Advanced study tools such as Failure Mode and Effects Analysis (FMEA)

Benefits: – Develop industry trends

– Positive or negative position against that trend

In-service Study

MLG Tire Wear

• Industry trends demonstrate that Mean Time To Repair (MTTR) of tires are 200 cycles

• Your MTTR is 80 cycles

• Create a study to determine root cause – Pilots were found to use excessive high speed

turning in order to make first runway exit

– Pressure gage out of calibration

Logistics

• Listing of spare parts

• Part pooling within local region

• Parts for rent – AOG issues

• Consumables – Hardware (fasteners, rivets, etc.)

– Short shelf life materials (i.e. adhesives, paints, etc.)

– Repair materials

Forums

• Specific A/C models

• Systems breakdown by ATA chapters

• Structures are broken down by zones

• Options for logistics

Scope of the Problems

Damage type: • Crack • Corrosion • Dent/Impact • Excessive load • Wear • Other

Maintenance Action: • Repair

• Replace

• Rig

Repair types: • Category A - Permanent repair

• Category B - Permanent repair with repetitive inspections

• Category C -Life limited temporary repair

Damage item:

• Part number

• Zone - Structural

• ATA Chapter – Engine/Avionics/Systems

Summary: Fleet Resolution Process Recommendations: 1) Create a pre-M&O operator conference to review and prioritize

problems 2) Create an agenda to approach OEMs for solutions

– Improve Structural Repair Manual (SRM) • Allowable Damage Limits (ADL) • Structural repairs

– Leverage Service Bulletins (SB) to fix problems – Improve Aircraft Maintenance Manual (AMM)

3) Share fleet metrics with other operators at M&O meetings to encourage participation

• Start online collaborating on production and in-service issues

• In as few as 10 - 20 operators actively reporting concerns and findings; trends will quickly appear

• Use forums for problem solving and aid with logistics

• Ability to easily save $$$$$$ over the life the aircraft

Closing: Fleet Colaboration