Commonwealth legislation

AD/PMC/14 Amdt 10 - Threaded Propeller Hubs

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Commonwealth

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legislative instrument

Plain English Summary

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Mandates inspections of all McCauley threaded propeller hubs to detect dye‑oil leaks, cracked hubs, blade looseness, missing expansion lock plugs, and to require lubrication of the steel shim/circlip in the blade retention ferrule. Threaded hubs are identified by part‑number numerals after the “C” being less than 200. (Requirement: inspection steps 1–4.)

This affects aircraft owners/operators with affected hubs, who must inspect (and, where required, remove) propellers within specified service‑hour windows and at 125‑hour reinspection intervals; operators bear the inspection, removal and maintenance costs. (Compliance.)

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Current sections

Direct links to the current provisions in AD/PMC/14 Amdt 10 - Threaded Propeller Hubs.

AD/PMC/14 Amdt 10 - Threaded Propeller Hubs

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Propellers - Variable Pitch - McCauley

AD/PMC/14

Amdt 10

Threaded Propeller Hubs 4/95

Applicability: All McCauley threaded propeller hubs.

Note: To identify a threaded hub, inspect hub P/N. If numerals after the “C” are less than 200 the hub is of the threaded type. e.g. 2AF34C17. If numerals after the “C” are 200 or higher hub is non threaded hub and the requirements of this Directive do not apply. e.g. B2A34C205.

Requirement: 1. Remove spinner and check whether hub is a dye oil filled or non dye oil filled type.

2. If hub is a dye oil filled type visually check hub for signs of dye oil leaks. If the spinner backing plate prevents a thorough hub inspection, removal of the propeller and backing plate will be required. If the inspection confirms there is no leakage from the hub and the correct quantity of dye oil is contained in the hub no further action is required and this Directive may be certified as complied with. If any dye oil leakage is apparent, the propeller is to be removed from service for dismantling and internal hub inspection procedures.

Note: To check for correct oil level, place two bladed propeller vertical. In a three bladed propeller the number one blade should be vertical. Remove oil filler plug, which should be approximately at the ten o’clock position and confirm dye oil level is to bottom of oil filler hole.

3. If hub is a non oil filled type or is not currently dye oil filled, remove propeller from engine and remove backing plate, if fitted. Using Group 1 dye penetrant to CAO 108.10 inspect hub in the following areas:

Note: Ensure solvent does not enter blade socket area as loss of lubricant from this area can affect blade pitch change action.

(a) the outer 38 mm (one and one half inches) of the complete circumference of each blade socket paying particular attention to the rear segment of each socket;

(b) the rear circumference of the hub barrel adjacent to the attachment face, including the complete mounting flange face; and

(c) inspect blades for excessive looseness and ensure both expansion lock plugs are installed in each blade retention nut.

4. After completion of dye penetrant inspection lubricate the area where the steel shim/circlip are mounted in the blade retaining ferrule using Aeroshell W65. If Aeroshell W65 is unavailable any SAE 10W or SAE 10W multi-grade piston engine oil is acceptable.

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Compliance: For propellers installed on aircraft certificated in the Agricultural or Acrobatic Category and which are known to have exceeded 400 hours total time in service - Unless previously carried out, within 100 hours time in service (TIS) from 30 March 1995. Thereafter, reinspect at intervals not exceeding 125 hours TIS.

For propellers installed on an aircraft certificated in other than Agricultural or Acrobatic Category and which are known to have exceeded 700 hours total time in service - Unless previously carried out, within 100 hours time in service (TIS) from 30 March 1995. Thereafter, reinspect at intervals not exceeding 125 hours TIS.

Background: Recently there have been several cases where failure to detect a cracked hub has resulted in the loss of a propeller blade. This Directive was previously amended to require non dye oil filled propellers to be removed and inspected using red dye penetrant, and a warning to operators of potential pitch change problems if solvent is allowed to enter the blade socket area. This amendment is raised in sequence to require inspection for blade looseness, presence of expansion lock plugs and lubrication of the steel shim/circlip mounted in the blade retention nut.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/PMC/14 Amdt 10 - Threaded Propeller Hubs

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Propellers - Variable Pitch - McCauley

AD/PMC/14

Amdt 10

Threaded Propeller Hubs 4/95

Applicability: All McCauley threaded propeller hubs.

Requirement: 1. Remove spinner and check whether hub is a dye oil filled or non dye oil filled type.

2. If hub is a dye oil filled type visually check hub for signs of dye oil leaks. If the spinner backing plate prevents a thorough hub inspection, removal of the propeller and backing plate will be required. If the inspection confirms there is no leakage from the hub and the correct quantity of dye oil is contained in the hub no further action is required and this Directive may be certified as complied with. If any dye oil leakage is apparent, the propeller is to be removed from service for dismantling and internal hub inspection procedures.

3. If hub is a non oil filled type or is not currently dye oil filled, remove propeller from engine and remove backing plate, if fitted. Using Group 1 dye penetrant to CAO 108.10 inspect hub in the following areas:

Note: Ensure solvent does not enter blade socket area as loss of lubricant from this area can affect blade pitch change action.

(a) the outer 38 mm (one and one half inches) of the complete circumference of each blade socket paying particular attention to the rear segment of each socket;

(b) the rear circumference of the hub barrel adjacent to the attachment face, including the complete mounting flange face; and

(c) inspect blades for excessive looseness and ensure both expansion lock plugs are installed in each blade retention nut.

4. After completion of dye penetrant inspection lubricate the area where the steel shim/circlip are mounted in the blade retaining ferrule using Aeroshell W65. If Aeroshell W65 is unavailable any SAE 10W or SAE 10W multi-grade piston engine oil is acceptable.