Aviation Maintenance Management Starting Out. IntroductionIntroduction The Flight Line is a business Approx 1 billion will travel by end of decade

Aviation Maintenance Aviation Maintenance ManagementManagement

Aviation Maintenance Aviation Maintenance ManagementManagement

Starting Out

IntroductionIntroductionIntroductionIntroduction The Flight Line is a business Approx 1 billion will travel by end of decade Commerce, mail, defense and logistics by air 20% of every revenue dollar is maintenance Early days one person knew all systems Today systems very complex and

interdependent Competing priorities and dwindling resources

require expert management

ManagementManagementManagementManagement

Given Task to perform; Resources to make it happen; Time to accomplish Task

Strike harmony in the variables so that the end result is achieved

Align the personnel characteristics with the organization – which is the most regulated industry in the world and you have an extreme challenge

Key ElementsKey ElementsKey ElementsKey Elements

Flying is the safest mode of transportation 28 million refuse to fly and another 25 % of those

that do fly experience apprehensive behavior After a major air disaster, regulatory

changes often take effect Impacts maintenance practices and flight

revenues

Managerial ChallengesManagerial ChallengesManagerial ChallengesManagerial Challenges Schedule pressures, parts shortages,

equipment deficiencies, regulatory and agency compliance inspections, union pressures etc..

Technology advancements and diverse equip require perpetual training

Parts issues – no parts, cannibalization, aircraft on ground, weather conditions

Personnel issues – financial, family, substance abuse, late, no-show, vacations, trng, meetings – impact (touch labor)

Unscheduled Maintenance

Managerial ChallengesManagerial ChallengesManagerial ChallengesManagerial Challenges Aircraft out of service impacts –

crew training and readiness Lost of revenue (no passengers – and maint/labor

costs) Loss of customer loyalty (customer is price based)

Intent of course not to make you an expert maintenance manager but to expose you to the various influences and the functions and techniques of the job

Knowledge is power

Aviation Maintenance ManagementAviation Maintenance ManagementAviation Maintenance ManagementAviation Maintenance Management

Early Days of Aviation Inspections Early Evolution of Aircraft Maintenance Post World War II Aircraft Maintenance Modern Day Aircraft Maintenance Summary

IntroductionIntroductionIntroductionIntroduction

Aviation in the Beginning Today’s aircraft cargo holds are longer & sit higher than

the Wright Brother’s first flight Flight – 120 ft in 12 sec with an altitude of 10ft 747 freighter – 150 ft inside & sits16 ft off the deck

Safest Mode of travel Walking is far more dangerous than flying or

driving, per mile traveled: 0.16 deaths per 100,000,000 miles aboard an airplane. 1.4 deaths per 100,000,000 miles in a car. Almost 50 deaths per 100,000,000 miles walked.

Which type of flying is safer?Which type of flying is safer?

Type of Flight Fatalities per million flight

hours

Airliner (Scheduled and nonscheduled Part 121) 4.03

Commuter Airline (Scheduled Part 135) 10.74

Commuter Plane (Nonscheduled Part 135 - Air taxi on demand) 12.24

General Aviation (Private Part 91) 22.43

Sources: NTSB Accidents and Accident Rates by NTSB Classification 1998-2007

Odds of being involved in a fatal accident

Odds of being involved in a fatal accident

Odds of being on an airline flight which results in at least

one fatality

Odds of being killed on a single airline flight

Top 25 airlines with the best accident rates 1 in 5.4 million

Top 25 airlines with the best accident rates 1 in 9.2 million

Bottom 25 with the worst accident rates 1 in 159,119

Bottom 25 with the worst accident rates 1 in 843,744

Source: OAG Aviation & PlaneCrashInfo.com accident database, 1985 - 2009

Accidents and Fatalities by Phase of Flight

Accidents and Fatalities by Phase of Flight

Early days of AviationEarly days of AviationEarly days of AviationEarly days of Aviation “If God had meant for man to fly He would have given

us wings.” Many early pioneers:

Octave Chanute, Otto Lilienthal, Samuel P. Langley, Glenn Curtiss & Orville & Wilbur Wright

Most intriguing problem was finding a power plant that provided the sufficient power-to-weight ratio for flight

Wright Brothers (recognized as first) both engineers & mechanics Made 4 flights (Dec. 17, 1903,, Kitty Hawk, NC) 4th was 59

sec. for over 852 feet. Designed own engine, propeller, & aerodynamic tables First maintainers – when they melted cement to repair nut

holding the propeller shaft sprockets in place

InspectionsInspectionsInspectionsInspections

No such thing as scheduled maintenance Spark plug cleaning and occasional oil change

WWI French pilot cut engines to allow him to sweep down and drop bombs

Couldn’t restart because he failed to “burn” the oil off the spark plugs by blipping his ignition switch – forced to land he was captured

The “standard” practice was to land, remove, and clean plugs Wright Brothers favored simple skid landings over

wheeled gear (gain in power-to-weight ratio) Resulted in structural damage (On Condition)

Never performed preflight or post flight tasks Simple look to see any hanging or items missing No inspections of the structural elements (dry rot, cracking, corrosion) Repair or replace as required

Instrumentation was simple – no inspections

Promotion of FlightPromotion of FlightPromotion of FlightPromotion of Flight

First airline in US carried passengers from St. Petersburg to Tampa (Jan – Mar 1914)

Carried only 1 passenger at a time After WWI, airmail service began – if room, a

passenger may sit upon the mail US Gov’t encouraged operators to use bigger planes &

carry more passengers so they wouldn’t have to rely on mail contracts to stay in business

Early days – no navigational aids (only roads, railways), could not fly at night unless bonfires lit along the route

By 1929, 10,000 miles of lighted airways, 275 lighted airports, 1352 navigational beacons


Monetary prizes for aviation accomplishments WWI used aircraft as observation platforms

Migrated to pistols, shotguns and rifles with limited success

First machine guns mounted on upper wing of bi-plane Pilot had to stand to fire and still try to pilot aircraft Fuselage mounted to fire through propeller – led to prop

damage until invention of the interrupter gear

WWII brought massive surge in production Increased complexity brought potential failure Inspired preventive maintenance Material breakthroughs and powerplant advances

influenced maintenance programs


Scheduled Maintenance Programs Periodic inspections of structure and components and

component change-outs Periodic inspection was preventive Component change out or Time Change Item (TCI) was to

remove item before failure Unscheduled Maintenance was massive

Operating environment, battle damage and tactics stressed airframe beyond design limits, and accumulated flight hours

Mass production impacted reliability and maintainability– Took 117 days from contract to first flight

– No thought for maintainer accessability or inspection

– Components went where they could fit


1927 – 18,679 flew; 1931 – 385,000 flew After WWII, US has fostered the jet age Maintenance Inspection became a

discipline 1954, F-86D delivered to Korean theater of war Required 50-hr Periodic, 25-hr HPO (Hourly Post

Flight), and a preflight By definition - unsafe to fly after 50 flt hrs


50-hr periodic inspection: Items that never failed were checked and rechecked

resulting in maintainer induced failures (fasteners on panels); TCI components changed out – with no failures

Resulting in waste of man-hours and dollars Inspection changed to 100-hr and items for inspection

reduced No balance of aircraft usage to inspection

requirements Assumptions more inspections safer aircraft


Safety includes redundant systems Also includes:

Failure and damage tolerant designs Safety for flight loads Normal and emergency systems Interconnected electrical systems

Reliability is: “A measure of the probability that an item will survive

to a specified operating age or time, under specified operating conditions, without a failure”

Promotion of FlightPromotion of FlightPromotion of FlightPromotion of Flight From periodic inspection to phased inspection

Simply put same amount of items inspected just in increments ¼ now, ¼ next time etc. etc.

Isochronal Inspection based on number of days not flight hours (28 days, 180 day 365 day, etc)

Military provided insight into maintenance preventive maintenance, & inspection concepts

Civilian – “A” check; “B” check; “C” check and “D” check General Aviation – 100-hr; Time Before Overhaul (TBO), calendar inspections, time-in-

service inspection Key is aircraft require preventive or corrective maintenance at frequent

intervals Kind of operation; environmental conditions; storage facilities avail; age and construct

of aircraft

Modern Day Aircraft MaintenanceModern Day Aircraft MaintenanceModern Day Aircraft MaintenanceModern Day Aircraft Maintenance

Since deregulation it has become “survival of the fittest”

Cost of ownership – fuel, wash, oil, tires etc… Scheduled maintenance

Goal is to correct any deficiency before it occurs Checks cost money – labor and parts, fluids costs and loss of

passenger revenue when not flying Design Manufacturer can help reduce costs

Through before design specification of PBL (Performance Based Logistics)

Total up all Maintenance associated costs subtract from revenue from aircraft and you get profit or loss

Design & Role of ManufacturersDesign & Role of ManufacturersDesign & Role of ManufacturersDesign & Role of Manufacturers

Maintenance Man-hours per Flying hour (MMH/FH)

Cost to maintain a particular type of aircraft We can design perfect systems on paper but

we can not build perfect systems in the “real” world

Nothing is perfect

Design & Role of ManufacturersDesign & Role of ManufacturersDesign & Role of ManufacturersDesign & Role of Manufacturers Cost of Ownership and scheduled maintenance

are 2/3 of equation Unscheduled Maintenance – random failures Reliability studies have led to MTBF (Mean Time

Between Failure) – components / system guesstimated reliability factor

Induced failures – FOD, damage from servicing vehicles, maintenance malpractices

Inherent failures – delamination of composites, substandard bearings, inefficient seals etc.

No defect – A-799 or fault within tech data limits (require expenditure of maintenance resources)

Design & Role of ManufacturersDesign & Role of ManufacturersDesign & Role of ManufacturersDesign & Role of Manufacturers Present all data with respect to MMH/FH to

manufacturer Scheduled Maint – Unscheduled Maint – Cost of Ownership –

Good, Fast, Cheap Allocate Unscheduled MMH/FH by system A design engineer may be limited from making the

perfect system by technology or the state of the art within any facet of the design effort

Limited by ability, technique or economics Economics may force a redesign with reduced tolerances,

cheaper materials & gap between: perfect & “ perfect” realism

Role of the MechanicRole of the MechanicRole of the MechanicRole of the Mechanic

For the mechanic the gap between “perfect” & “perfect” realism always changes & predominantly for the worse

Components or systems tend to wear out from use or lack there of (time or environmentally related)

Misuse may cause premature deterioration or degradation of the system or even outright damage

The engineer’s responsibility is to design the system with as high degree of perfection within reasonable limits/constraints

The mechanic’s responsibility is to combat the gap between ideal & realism during the operational lifetime of the equipment

SummarySummarySummarySummary

The purpose of aircraft maintenance is to ensure the aircraft will remain airworthy throughout its operational life

Inspections & modifications to aircraft help ensure the programs are getting closer to “perfection” within the inherent limits possible

Documents

Aviation Maintenance Management Starting Out. IntroductionIntroduction The Flight Line is a business Approx 1 billion will travel by end of decade