Working Example Alternator Change

1
Working ExampleAlternator Change

• Mike Heusser, ACE-115N
• Peter Pupator, ACE-115N
• Mark Wilson, AAL-235

2
Alternator Change

• Replacement of an existing Alternator with a
  higher output alternator
• Cessna 207A. TCDS A16CE, Cert Basis 14 CFR part
  23 as amended 23-1 through 23-6 (14v electrical
  system serial number aircraft)
• Maximum aircraft weight 3800 lbs
• We are assuming the aircraft has a US
  registration
• We are assuming that the alternator has a good
  aviation service history

3
Initial Considerations

• Establish the correct aircraft certification
  basis
• For example
• 14 Code of Federal Regulations, Part 23
• Civil Air Regulations(CAR), Part 3
• Bureau of Air Commerce, Aeronautics Bulletin No.
  7-A
• Air Commerce Regulations

4
Initial Considerations

• Predecessor Regulations are still in effect for
  many certification projects
• Civil Air Regulations(CAR), Part 3
• Bureau of Air Commerce, Aeronautics Bulletin No.
  7-A
• Air Commerce Regulations

5
Initial Considerations

• Pulley Diameters (sets the alternator speed)
• Voltage regulator
• Torque limiting features
• Mounting brackets
• Cooling air requirements

6
Initial Considerations

• Over voltage protection
• Wire size and type
• Circuit protection (circuit breaker type)
• Electrical loads
• Electrical distribution system capacity

7
Required information

• Output voltage
• Maximum Alternator speed
• Minimum Alternator speed for rated output
• Maximum Alternator temperatures
• Maximum output current

8
Regulation and Possible method of compliance

• 14 CFR 23.601
• Section 3.291, when working with a CAR-3 aircraft
• Suitability of design details and parts
• Compliance can be shown by use and service
  history of parts on other aircraft.

9
Regulation and Possible method of compliance

• 14 CFR 23.603
• Section 3.292, when working with a CAR-3 aircraft
• Materials and workmanship
• Compliance can be shown by using standard
  materials or aviation type components.
• Workmanship of standard aviation practices.

10
Regulation and Possible method of compliance

• 14 CFR 23.611
• Section 3.296, when working with a CAR-3 aircraft
• Accessibility
• The unit must be installed such that access is
  available, in typical maintenance situations, for
  close examination (and adjustment) required for
  inspection, lubrication, or alignment.

11
Regulation and Possible method of compliance

• 14 CFR 23.1163
• Section 3.635, when working with a CAR-3 aircraft
• Power Plant accessories
• Bracket strength considerations.
• Use existing mounting on engine.
• Mount so as to avoid contact with flammable
  fluids and vapors. Do not mount in a possible
  low area where vapors can accumulate. Ventilate
  alternator properly.

12
Regulation and Possible method of compliance

• 14 CFR 23.1163 (continued)
• Power Plant accessories
• Expect to measure alternator temperatures at the
  critical condition
• Bearing temperatures
• Case temperatures
• Stator temperature
• Propose testing method
• Thermocouples, temp. sensitive labels
• On the ground or in the air?

13
Regulation and Possible method of compliance

• 14 CFR 23.1301
• Section 3.651, when working with a CAR-3 aircraft
• Easy Stuff
• Does the new alternator perform its intended
  function as related to the whole aircraft system.
• Have the switches been labeled.
• Does all of the other installed equipment
  function properly.

14
Regulation and Possible method of compliance

• 14 CFR 23.1322
• Does the system have a warning annunciator?
• If so, the annunciator must be amber colored

15
Regulation and Possible method of compliance

• 14 CFR 23.1351
• Sections 3.690, 3.693 3.687, when working with
  a CAR-3 aircraft
• Electrical loads must be established
• Loads can be found by analysis or measurement
  (Propose a test)
• MIL-E-7016F, Electrical loads analysis contains
  methods and procedure
• AC 43.13 latest revision

16
Regulation and Possible method of compliance

• 14 CFR 23.1357
• Sections 3.690 3.691 when working with a CAR-3
  aircraft
• Circuit breakers must be Trip Free
• Circuit breakers must be of the correct size
• Must be readily reset in flight
• If the alteration uses fuses, there must be
  spares available to the pilot
• Must be identified (labeled)

17
Regulation and Possible method of compliance

• 14 CFR 23.1361
• Section 3.688 3.689 when working with a CAR-3
  aircraft
• Must have a master switch to disconnect the
  alternator
• Master switch must be properly located
• Master switch must be easy to see
• Above items probably ok, if similar to the
  previously existing installation

18
Regulation and Possible method of compliance

• 14 CFR 23.1367
• Section 3.694, when working with a CAR-3
  aircraft
• Switches must be labeled
• Switches must be of adequate capacity and voltage
  rating
• Distance or Insulation of connecting wire.
• Vibration in flight cannot cause shorting.

19
Final Considerations

• Must have drawings or photos describing the
  installation.
• Must have Schematic and Distributions Diagrams
  (Part of ICA)
• Drawings/Photos need to indicate component part
  numbers and source of supply
• Reports Electrical loads, Other as required.
• Originals go with aircraft records 337, 8110-3,
  Reports, FMS
• I/A has no requirement to hold copies.