Proposed Airworthiness Directive - Propellers: Inspection and Overhaul

[old man emu]

CASA is proposing an amendment to AD/PROP/1 in order to set the maximum time between overhauls for propellers. Basically the proposed amendment to the Directive is to relate overhaul to the manufacturer's recommended flight hourly TBO or calendar TBO.

 

It is probably a good idea to apply the directive to RAA propellers to maintain good levels of safety.

 

In the case where there is no calendar TBO, the prop is then use to hourly TBO and at 6 years since new or last overhaul, or since the last Hub/Blade inspection, carry out a Hub/Blade Inspection.

 

If there is neither recommended flight hourly or calendar TBO, then carry out a Hub/Blade inspection and at 12 years since new, or last overhaul, or last "Bare Blade Inspection", carry out a Bare Blade Inspection.

 

For wooden or composite props, a visual inspection of the hub and blades for delamination, damage to the leading edges and thrust faces and crushing of the hub by mounting plates. Inspection for thrust bends and angles. Finally, balance in accordance with manufacturer requirements.

 

That last task will mean that the prop will have to go to a specialist prop shop.

 

OME

 

 

[fly_tornado]

ka ching!

 

 

[old man emu]

Yes, it is another expenditure, but the issue draws attention to the need to regularly give the whirly bit a bit of a closer look.

 

Periods of operation or elapsed calendar time are calculated from the date of initial installation. There is a permitted storage period of up to 2 years after manufacture, but the clock starts clicking at the end of two years of storage.

 

OME

 

 

[Ultralights]

and the safety case is?

 

 

[ave8rr]

and the safety case is?

Probably overseas experience is dictating this. Most countries have the 12 year inspection. More frequent if on manufacturers recommendation.

Probably more of a concern with Variable pitch Propellers which would include those used on ultralights.

 

 

[old man emu]

No. Not all coming from overseas instances. There are plenty of unloved props in this girted land. The CASA AD/PROP/1 Amdt 2 currently in force specifically excludes RAA and sport Rotorcraft aircraft. Amendment 3 "applies to all propellers".

 

Variable pitch props each have a log book, so keeping the maintenance up to date is easy. Fixed Pitch Props (wood, composite or metal) don't have a log book, so their maintenance is not so rigidly controlled. Wooden props don't have a TBO, however they are covered under AWB 61-007, http://www.casa.gov.au/wcmswr/_assets/main/airworth/awb/61/007.pdf

 

OME

 

 

[robinsm]

Dont even know if my Brolga has a TBO?

 

 

[old man emu]

Dont even know if my Brolga has a TBO?

I'm amazed that the owner of an aircraft doesn't do the most basic enquiry regarding it maintenance.

 

I've just typed in "brolga propeller" to Google and got this hit: http://www.competitionaircraft.com/Brolga.htm from which I got this:

 

Maintenance

 

The propeller has no definite life. An expectation of 2,000+ hours is not unrealistic, provided the proper inspection and maintenance schedule as follows is adhered to:

 

 

 

1. Every 20 hours, retorque blade bolts to 124-150 inch lb. And prop mounting bolts to appropriate value in table 2.

 

 

 

2. Every 200 hours, dismantle prop and inspect all parts for cracks and/or wear. Visually check the bolts and bolt holes and the "spline" area where the blades and pitch blocks are joined. No wear or elongation is allowed. Patches of surface corrosion on the blade bolts dictates replacement. Replace any defective parts. Inspect the blades for water ingestion or delamination.

 

 

 

3. Any prop strike is cause for a complete disassembly and inspection as described in #2 above. The presence of any stress fracture emanating from the bolt holes in the blades dictates blade replacement.

 

 

 

4. Every 1000 hours, replace all hardware.

 

No wonder CASA has to issue stringent ADs to get owners to look after the safety of their airplanes.

 

OME

 

 

[robinsm]

Competition aircraft are the american company who sell the eqivalent design, it does vary in some small ways. I have bought parts from them before, and do follow the recommendation but as far as I know there are no specs for the australian made version that was bought out, and not now manufactures by bolly. I agree, anyone with any common sense would follow at least a basic maintanence schedule on their prop, it was the lack of info from the original local manufacturer I was commenting on. (case in point, the pitch blocks from the american manufacturer have to be redrilled to handle the Oz supplied bolts etc.

 

 

[ave8rr]

I'm amazed that the owner of an aircraft doesn't do the most basic enquiry regarding it maintenance.I've just typed in "brolga propeller" to Google and got this hit: http://www.competitionaircraft.com/Brolga.htm from which I got this:

 

Maintenance

 

The propeller has no definite life. An expectation of 2,000+ hours is not unrealistic, provided the proper inspection and maintenance schedule as follows is adhered to:

 

 

 

1. Every 20 hours, retorque blade bolts to 124-150 inch lb. And prop mounting bolts to appropriate value in table 2.

 

 

 

2. Every 200 hours, dismantle prop and inspect all parts for cracks and/or wear. Visually check the bolts and bolt holes and the "spline" area where the blades and pitch blocks are joined. No wear or elongation is allowed. Patches of surface corrosion on the blade bolts dictates replacement. Replace any defective parts. Inspect the blades for water ingestion or delamination.

 

 

 

3. Any prop strike is cause for a complete disassembly and inspection as described in #2 above. The presence of any stress fracture emanating from the bolt holes in the blades dictates blade replacement.

 

 

 

4. Every 1000 hours, replace all hardware.

 

No wonder CASA has to issue stringent ADs to get owners to look after the safety of their airplanes.

 

OME

And that's why it won't be long before an annual inspection by an independent person/authority will be required.

 

 

[spacesailor]

SO. Who or what authority will inspect MY home carved props, and those of other forum members props.

 

(Information included in AAC 187-1. The following information does

 

not constitute approved data.)

 

spacesailor

 

 

[old man emu]

Here's the link to the proposed amendment: www.casa.gov.au/ADFiles/equip/prop/PAD-PROP-001.pdf

 

Read Appendix 1 to see what's involved in a hub/blade inspection.

 

As the manufacturer of the prop, you have the one who sets the manufacturer's requirements for the prop, including TBO and balancing criteria. Therefore, you don't have to get anyone else involved unless you want to sub-contract any of the work.

 

OME