393SYS Airport Engineering Practice Lecture 5 Engineering & Production

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393SYS Airport Engineering Practice Lecture
5Engineering Production
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6.0 Engineering
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• Introduction
• There is an on-going, open discussion in the
  aviation industry about whether or not an
  airline needs an engineering department.
• At one time, airlines decided what they wanted
  in terms of aircraft
• - size
• - range
• - operating systems
• In more recent years, however, the trend has
  been to leave the design and development of new
  aircraft to the aircraft manufactures.
• The airlines ask only that these manufacturers
  build something we can use effectively and
  something we can afford.

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• This situation has led many airlines to actually
  reduce their engineering staff.
• However, there are still good reasons for hiring
  people with engineering skills and background.
• Engineers are usually identified by some
  speciality civil, mechanical, electrical,
  aeronautical, transportation, nuclear, etc.
• However, none of these specialisms apply
  directly to aviation except aeronautical
  engineering.
• What is really needed in a typical airline
  maintenance organization are people trained as
  maintenance engineers.
• This type of engineer would need to know basic
  engineering as well as the technical details of
  the equipment used in aviation, and in the
  maintenance and operation of that equipment.

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• If employed by aircraft manufacturers, these
  engineers would develop maintenance programs
  from MSG-3 activity and also produce the various
  documents identified in last weeks lecture.
• However, most colleges and universities do not
  have courses in maintenance engineering.
• Note that the engineering department of an
  airline can vary widely.
• The size of the airline often determines the
  function provided by the engineering department.
• Ideally, an airline engineering department would
  have both
• engineers with a degree in engineering, and
• senior licensed mechanics

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• Mechanics and Engineers
• Mechanics know the details of systems and
  components on aircraft and are experienced in
  the rules and regulations of maintenance.
• However, they tend not have had the same
  analytical training as graduates of engineering.
• Engineering graduates, on the other hand, often
  lack a detailed understanding of aircraft,
  aircraft engines, and the multitude of systems
  and components need in aircraft.
• Mechanics
• Mechanics, and technicians study the practical
  aspects of aviation systems.

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• They specialize in avionics systems
• electrical, electronic, communications,
  computers
• or hydraulic systems
• hydraulics, pneumatics, flight controls and
  structures.
• A mechanic is trained to understand how each
  system or unit is supposed to work, and how it
  is supposed to be operated.
• When there is a discrepancy, the mechanic
  follows standard procedures for trouble
  shooting, fault isolation, and repair.
• Procedures for removal, and installation, as
  well as for testing the installed unit, are all
  standardized.
• An experienced mechanic also knows what kinds of
  things can go wrong in operation, installation
  and in testing.

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• However, no matter how well trained a mechanic
  may be, and no matter how much experience he or
  she might have, there are often problems that
  cannot be resolved with these standard
  approaches.
• It might then be necessary to dig deeper than
  the standard approaches or else call upon the
  engineering staff for help.
• Engineers
• The term engineer is usually reserved for those
  who have academic degrees in some engineering
  field.
• These people are trained differently than
  mechanics.
• Engineers are trained in the basics of science
  and engineering.

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• They are also trained in
• - the techniques of inductive and deductive
  reasoning
• - statistical analysis
• - problem solving, and
• - systems engineering.
• They will generally specialize in one particular
  kind of engineering electrical, mechanical,
  aeronautical, structural.
• If all the usually effective procedures applied
  by the mechanic fail, then the engineer must
  begin by looking at the problem from a new
  angle.
• The engineer must be capable of developing new
  and innovative procedures for studying and
  analyzing problems, and must understand the big
  picture.

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Homework Exercise Read through Appendix C
(trouble shooting techniques), and Appendix D
(problem solving example)

• One important thing for all the engineer knows
  about engineering, problem solving, and about
  systems and their interactions, he or she must
  know about the airplanes, the engines, and their
  associated systems to effectively apply this
  knowledge to the solution of real airplane
  problems.
• It therefore takes both disciplines
  engineering and maintenance as well as both
  types of experts engineers and mechanics for
  a maintenance and engineering organization to
  run smoothly.

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• Engineering Department Functions
• Each model of aircraft has an initial
  maintenance program developed by an Industry
  Working Group.
• The initial maintenance program is a generalized
  program and must be tailored to the individual
  airline operators requirements from the very
  beginning.
• The manufacturer produces the FAA approved MRB
  report and a maintenance planning document.
• It is the responsibility of the engineering
  department of the airline to package these tasks
  into workable units based on factors such as
• time, space, personnel, fleet schedules, and
  overall airline capabilities.

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• Aircraft Maintenance Checks (from
  http//en.wikipedia.org/wiki/C_Check)
• Aircraft maintenance checks are periodic checks
  that have to be done on all aircraft after a
  certain amount of time or usage.
• Airlines casually refer to these checks as one
  of the following A check, B check, C check, or
  D check.
• A and B checks are lighter checks, while C and D
  are considered heavier checks.
• A Check This is performed approximately every
  month.
• This check is usually done overnight at an
  airport gate.

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• The actual occurrence of this check varies by
  aircraft type, the cycle count (takeoff and
  landing is considered an aircraft "cycle"), or
  the number of hours flown since the last check.
• The occurrence can be delayed by the airline if
  certain predetermined conditions are met.
• B Check This is performed approximately every 3
  months.
• This check is also usually done overnight at an
  airport gate. A similar occurrence schedule
  applies to the B check as to the A check.
• C Check This is performed approximately every
  12-18 months.
• This maintenance check puts the aircraft out of
  service and requires plenty of space - usually
  at a hangar at a maintenance base.

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• The schedule of occurrence has many factors and
  components as has been described, and thus
  varies by aircraft category and type.
• D Check This is the heaviest check for the
  airplane.
• This check occurs approximately every 4-5 years.
  
• This is the check that, more or less, takes the
  entire airplane apart for inspection.
• This requires even more space and time than all
  other checks, and must be performed at a
  maintenance base.

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• The A and B checks are no problem for airlines
  because they do not take the aircraft out of
  service.
• Large airlines have a large fleet of aircraft -
  enough for the airline to schedule people and
  facilities for regular C checks e.g. one
  airplane per week or month.
• In small airlines, there are not enough
  airplanes or manpower for the regular scheduling
  of C checks.
• To solve this problem, the C check is divided
  into parts, called phases, and each phase is
  conducted separately.
• For example, a C check could be divided into
  four phases C1, C2, C3 and C4 each one
  carried out every 3 months until the entire C
  check is performed.

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• Alternatively, a C check could be divided into
  12 packages with one package completed every
  month together with the A check.
• In both cases, the manpower utilization is more
  constant throughout the year.
• The airline engineering department is
  responsible for selecting the tasks to be done,
  for packaging the tasks into workable packages,
  and for ensuring that all task time limits are
  met.
• The Production, Planning and Control
  department is then responsible for scheduling
  the checks.
• The tasks to be performed by the maintenance
  unit of the airline at any of these checks can
  be quite detailed.
• To endure that they are carried out correctly,
  tasks cards are issued to the mechanics.

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• Evaluation of New Aircraft for the Airline Fleet
• One of the primary functions of an airline
  engineering department is to evaluate new
  equipment for the airline.
• A typical question here is What
  airplane/engine combination should we buy ?
• The answer to this question will be influenced
  by
• the routes to be flown and the destination
  cities
• the expected market share
• the cost of the equipment
• Another important question, however, is What is
  the best equipment to buy from the standpoint of
  maintenance and engineering ?

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• There exists a trade-off here between technical
  priorities and business priorities. The
  following example focuses only on technical
  priorities from a maintenance point of view
• Example
• Boeing 767 or Airbus A330 ?
• There are a number of questions to be answered
  in regard to maintenance
• 1. Engines
• What engines are available for these models ?
• Are they the same or similar to engines in the
  airlines current fleet ?
• Note that is question is important because there
  may be a need for additional maintenance and test
  facilities for these new engines.

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• 2. Aircraft Range
• What is the range of these airplanes ?
• Will the airline need to position their own
  personnel at outstations or arrange for contract
  personnel at the site to support maintenance.
• Can existing outstation personnel handle these
  new airplanes ?
• Can they do so with or without additional
  training ?
• 3. New Technologies
• What new technology is included in these new
  models ?
• Are the skills of the current maintenance and
  engineering staff sufficient to maintain these
  new airplanes or will they require additional
  training ?

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• 4. Maintenance Check Schedules
• Will the maintenance check schedules for the new
  aircraft be compatible with the current
  schedules for the existing fleet ?
• 5. Ground Support
• Will additional ground support equipment (GSE)
  be needed for these new aircraft ?
• If so, what equipment ?
• 6. Hangers
• Will the existing hangers be suitable for these
  airplanes ?
• Will they need to be modified or will a new
  hanger be required ?

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• 7. Aircraft Parts
• What new aircraft parts, and storage for parts,
  will be required at both the home base and the
  outstations to support the new airplanes ?
• Could this involve a considerable amount of
  financial investment for parts not common to the
  existing fleet ?
• 8. Industry Experience
• What is the industry experience on these new
  aircraft relative to maintenance ? i.e.
• parts availability ?
• parts delivery ?
• failure rates ?
• removal rates ?
• amount of maintenance required ?

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Engineering
Question What new aircraft would probably require
the most changes in ME support ?
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• Evaluation of Used Aircraft for the Airline Fleet
• If the airline is considering leasing used
  aircraft, then other items must be considered.
• These items would include information on
• the engine type
• the maintenance program and check schedule
• the status of any modifications to the aircraft
  e.g. AD SB
• Questions to be asked would include
• Are the above the same as, similar to, or
  different from your airlines equipment ?
• How will this affect training, maintenance
  support, etc. ?

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• What modification and configuration standards
  must be met by the operator or by the lessor ?
• What configuration should the airplane be in at
  the termination of the lease ?
• Example
• An aircraft in ETOPS configuration is leased to
  an airline. The airline did not need the ETOPS
  capability and did not keep up with the newer
  ETOPS modifications. When the aircraft was
  returned at the end of the lease, the airline
  discovered that they were responsible for
  returning the airplane to ETOPS configuration at
  their own expense. Note that the condition of the
  aircraft at termination of the lease should be
  clearly stated and understood.
• ETOPS Extended Range Operations with
  Two-Engine Airplane (e.g. Boeing 777 ER)

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• Other functions of an airline engineering
  department include
• Evaluation of the need for new equipment in
  support of aircraft added to the fleet.
• The requirements for new facilities such as
  hangars, engine test facilities, component
  shops, and storage facilities.
• The issuing of engineering orders (EOs)
• Any work performed by maintenance in the form of
  standard checks A, B, C checks is perfumed
  on standing orders from the airline Vice
  President of ME, as identified in the
  maintenance section of the Ops Spec.
• Any work not included in these standard checks
  must be assigned by an engineering order.

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7.0 Production Planning and Control

• Introduction
• The Production Planning and Control (PPC)
  activity within an airline is one of the key
  organizations within ME.
• It is actually the heart of the maintenance
  organization.
• The title implies two functions planning and
  control.
• Actually, PPC has three primary functions
  forecasting, planning, and control.
• Forecasting includes the estimated maintenance
  workload for the long term and short term based
  on the existing fleet and business plans, and on
  any known changes in these for the forecast
  period.

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7.0 Production Planning and Control

• Planning involves the scheduling of upcoming
  maintenance and includes the planning and
  scheduling of all manpower, parts, facilities,
  and time frame requirements.
• Control allows adjustment of the plan and keeps
  (or attempts to keep) the check on schedule.
• There are several methods of adjusting the plan,
  including
• deferral of maintenance to a later check,
• addition of personnel to complete the work,
• outsourcing the work to a contractor
• Feedback from a check allows PPC to adjust the
  planning effort for future checks.

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7.0 Production Planning and Control

• Without planning, action would be impulsive and
  produce unpredictable results.
• The diagram below illustrates how work in
  expended on a typical project with and without
  proper planning

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7.0 Production Planning and Control

• The preliminary planning consists of the
  development of a maintenance program and its
  schedule.
• With proper planning, once the check has begun,
  the work progresses smoothly (dashed yellow
  line).
• Without preliminary planning, the effort swells
  as the work progresses, mostly due to unexpected
  events and delays (solid red line).

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7.0 Production Planning and Control

• Example for C Check
• Normally, a C check requires about 4 or 5 days.
• A new airline operator started to consult the
  maintenance manual for the C check one week
  before the check was due.
• Without adequate preplanning, the C check took 4
  weeks to perform !
• The goals of PPC are -
• to maximize the ME contribution to the airline
• to plan and organize work prior to execution
• to adjust plans and schedules to meet changing
  requirements

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7.0 Production Planning and Control

• Production Planning
• The goal of ME is to deliver airworthy vehicles
  to the flight department in time to meet the
  flight schedule, with all maintenance activities
  completed or properly deferred.
• The airline engineering department will have
  developed the maintenance plan from the MRB
  (Maintenance Review Board report) or Ops Specs
  document and divided the work into appropriate
  work packages indentifying
• the tasks to be done
• the intervals at which they will be done, and
• the manpower requirements for each task.
• The check package schedule for a typical
  mid-sized airline is shown in the following
  table

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7.0 Production Planning and Control
From Aviation Maintenance Management,
H.A.Kinniston, McGraw-Hill 2004. FH Flight
Hours, HMV Heavy Maintenance Visit
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7.0 Production Planning and Control

• PPC must now take this engineering package and
  then plan, schedule and adjust the work for each
  check and for each aircraft.
• The estimated man hours for the various checks
  and aircraft for the same mid-sized airline are
  as follows

From Aviation Maintenance Management,
H.A.Kinniston, McGraw-Hill 2004.
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7.0 Production Planning and Control

• Daily, 48-hour and transit checks are usually
  standardized and require little or no effort on
  the part of PPC other than scheduling.
• All A checks and higher are planned,
  scheduled, and coordinated by PPC and their
  content varies from check to check.
• These activities are more involved than the
  daily, 48-hour and transit checks, so the
  panning is started well in advance of the actual
  check.
• For A checks, planning begins 1 to 2 weeks
  prior to the scheduled check.
• For C checks, planning begins about 4 weeks in
  advance.

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7.0 Production Planning and Control

• Maintenance Tasks for Less-than-A-Check
  Intervals
• Certain items in the MRB report must be checked
  daily, bi- weekly, and weekly.
• The scheduling is the responsibility of PPC.
• These checks can be scheduled overnight, or at
  certain turn- around times, or may be included in
  the A checks.
• This is up to the airline and is usually
  determined by local conditions and man-power
  availability.
• Airlines can experience problems if they defer
  these tasks day after day due to heavy work
  loads.
• The deadline for completion gets nearer and
  nearer and, finally, the airline has to take the
  aircraft out of service for several hours to get
  the work done without exceeding FAA time limits.
  These delays can be costly.

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7.0 Production Planning and Control

• Multiple Checks
• Some MRB items are done at intervals like every
  other every third check. This is true for A C
  checks. That means that different A check
  have different task set and require different
  amount of time depending on where that A check
  is in the maintenance cycle.
• The following table shows a typical aircraft A
  check and C check schedule

From Aviation Maintenance Management,
H.A.Kinniston, McGraw-Hill 2004.
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7.0 Production Planning and Control

• Every C check includes all the A check
  items.
• The C check items can also be scheduled for
  longer intervals.
• A chart similar to the one on the previous slide
  can be drawn for multiple C checks.
• Phased Checks
• These are different from multiple checks.
• An A check may be split into two phases, each
  one performed on successive nights to minimize
  maintenance crew needs and down time.
• The right side of an aircraft might be done on
  the first phase (called an A1 check and the
  left side on the second phase (the A2 check).

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7.0 Production, Planning and Control

• A C check may be broken down into four parts
  (C1, C2, C3, and C4) and performed every 3
  months or so depending on the full C check
  cycle.
• The C check can also be divided into 12 parts,
  with one part being completed each month (C1,
  C2, C12).
• The table on the following slide shows a typical
  airline estimate for the man-hours planned for a
  C check on the Airbus A300B4.
• The check will consist of three categories of
  task routine, variable routine, and
  non-routine.
• Routine tasks are identified in the MRB report
  document.
• Variable routine tasks vary from one check to
  another and from one aircraft to another.
• Nonroutine tasks are generated by the
  accomplishment of other, routine tasks.

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7.0 Production Planning and Control
From Aviation Maintenance Management,
H.A.Kinniston, McGraw-Hill 2004.
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Summary

• Summary
• Engineering
• Introduction
• Mechanics and Engineers
• Engineering Department Functions
• Aircraft Maintenance Checks
• Evaluation of New and Used Aircraft for the
  Airline Fleet
• Production Planning and Control
• Introduction
• Production Planning
• Maintenance Tasks for Less-than-A-Check
  Intervals
• Multiple Checks
• Phased Checks

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What you need to know for the exam !

• Why do all airlines require a maintenance
  department, regardless of whether or not they
  actually do the maintenance themselves ?
• Explain the difference between mechanics and
  engineers in terms of their role in aircraft
  maintenance.
• What is the MRB report, who is responsible for
  producing it and what are airlines required to
  do with it ?
• Explain, briefly, what is meant be aircraft A,
  B, C and D checks.
• What approach is adopted by small airlines in
  conducting C checks ?
• What issues need to be addressed in evaluating
  new (used) aircraft for an airline fleet ?
• Explain, briefly, the function of Production
  Planning and Control department within an
  airline ?
• What is the relationship between Engineering and
  PPC in an airline ?
• Explain the purpose of Production Planning.
• Explain Multiple Checks and Phased Checks
  and also the difference between the two.