It it time to get dressed?

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Gone Flyin

Pre-takeoff checklist
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Gone Flyin
When was the last time you dressed your prop?

Your AP/IA is supposed to do it on every annual. None of mine ever has.... what about yours?

Be that as it may, I do my own.

According to the POH for my Cessna 150 "small nicks in the leading edge of the propeller can cause stress cracks and should be dressed out as soon as possible".

I set my prop on a small ladder so it will not move as I work on it. Then, I look/feel for any defects on the leading, the top edge on each side. The safest way to dress them out is to use Scotch-Brite pads. They make them from 60 grit all the way down to 1500 grit.

prop1.jpg


I use their Greener Clean pads (#6448) 600 grit made from plant materials. They will not take off much metal but will clean up any corrosion and chipping paint. With the prop supported, it's easy for me to run the pads up and down the top edge and get a smooth finish.

I follow this up with a good wiping using Stoddard Solvent and then I apply a paste wax.

Another inspection our AP/IA is supposed to do is a tracking test on the prop. Ever seen yours do that?

prop2.jpg


This makes sure both sides of the prop are rotating in the same plane. A simple test that is critical to the health of your prop... and to you.

This book is a must-have for us GA plane owners. Get one for yourself. Mine is from 1998 but so what. My plane is from 1975. Cost me $3 on Ebay.


prop3.jpg



We need to know what our mechanics are supposed to be doing... and are not... to our planes.
 
Gone Flyin said:
When was the last time you dressed your prop?

Your AP/IA is supposed to do it on every annual. None of mine ever has.... what about yours?

Be that as it may, I do my own.

According to the POH for my Cessna 150 "small nicks in the leading edge of the propeller can cause stress cracks and should be dressed out as soon as possible".

I set my prop on a small ladder so it will not move as I work on it. Then, I look/feel for any defects on the leading, the top edge on each side. The safest way to dress them out is to use Scotch-Brite pads. They make them from 60 grit all the way down to 1500 grit.

prop1.jpg


I use their Greener Clean pads (#6448) 600 grit made from plant materials. They will not take off much metal but will clean up any corrosion and chipping paint. With the prop supported, it's easy for me to run the pads up and down the top edge and get a smooth finish.

I follow this up with a good wiping using Stoddard Solvent and then I apply a paste wax.

Another inspection our AP/IA is supposed to do is a tracking test on the prop. Ever seen yours do that?

prop2.jpg


This makes sure both sides of the prop are rotating in the same plane. A simple test that is critical to the health of your prop... and to you.

This book is a must-have for us GA plane owners. Get one for yourself. Mine is from 1998 but so what. My plane is from 1975. Cost me $3 on Ebay.


prop3.jpg



We need to know what our mechanics are supposed to be doing... and are not... to our planes.
Click to expand...

My AP/IA rings my prop in a effort to detect cracks. Do you remove spinner every annual to check prop bolts torque? Your suppose to. I do.

After all that then it's time for a dynamic balance if you want your prop in top shape.
IMG_9334.JPG

A balanced prop can increase the performance of your plane.
006(1).JPG


You can actually hear a well balanced prop on climb out from the runway.
008(1).JPG


IMG_8220.JPG
 
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Gone Flyin said:
When was the last time you dressed your prop?

Your AP/IA is supposed to do it on every annual. None of mine ever has.... what about yours?

Be that as it may, I do my own.

According to the POH for my Cessna 150 "small nicks in the leading edge of the propeller can cause stress cracks and should be dressed out as soon as possible".

I set my prop on a small ladder so it will not move as I work on it. Then, I look/feel for any defects on the leading, the top edge on each side. The safest way to dress them out is to use Scotch-Brite pads. They make them from 60 grit all the way down to 1500 grit.

prop1.jpg


I use their Greener Clean pads (#6448) 600 grit made from plant materials. They will not take off much metal but will clean up any corrosion and chipping paint. With the prop supported, it's easy for me to run the pads up and down the top edge and get a smooth finish.

I follow this up with a good wiping using Stoddard Solvent and then I apply a paste wax.

Another inspection our AP/IA is supposed to do is a tracking test on the prop. Ever seen yours do that?

prop2.jpg


This makes sure both sides of the prop are rotating in the same plane. A simple test that is critical to the health of your prop... and to you.

This book is a must-have for us GA plane owners. Get one for yourself. Mine is from 1998 but so what. My plane is from 1975. Cost me $3 on Ebay.


prop3.jpg



We need to know what our mechanics are supposed to be doing... and are not... to our planes.
Click to expand...
Maybe you’re an A&P. Or maybe you have an experimental airplane. If not, you might think about removing a post in which you confess to non-approved owner-performed maintenance.
 
OneCharlieTango said:
Maybe you’re an A&P. Or maybe you have an experimental airplane. If not, you might think about removing a post in which you confess to non-approved owner-performed maintenance.
Click to expand...

If the A&P looks at it afterwards, what's the problem? I can't count the number of times I've done "outlawed" maintenance.
 
Gone Flyin said:
When was the last time you dressed your prop?

Your AP/IA is supposed to do it on every annual. None of mine ever has.... what about yours?

Be that as it may, I do my own.

According to the POH for my Cessna 150 "small nicks in the leading edge of the propeller can cause stress cracks and should be dressed out as soon as possible".

I set my prop on a small ladder so it will not move as I work on it. Then, I look/feel for any defects on the leading, the top edge on each side. The safest way to dress them out is to use Scotch-Brite pads. They make them from 60 grit all the way down to 1500 grit.

prop1.jpg


I use their Greener Clean pads (#6448) 600 grit made from plant materials. They will not take off much metal but will clean up any corrosion and chipping paint. With the prop supported, it's easy for me to run the pads up and down the top edge and get a smooth finish.

I follow this up with a good wiping using Stoddard Solvent and then I apply a paste wax.

Another inspection our AP/IA is supposed to do is a tracking test on the prop. Ever seen yours do that?

prop2.jpg


This makes sure both sides of the prop are rotating in the same plane. A simple test that is critical to the health of your prop... and to you.

This book is a must-have for us GA plane owners. Get one for yourself. Mine is from 1998 but so what. My plane is from 1975. Cost me $3 on Ebay.


prop3.jpg



We need to know what our mechanics are supposed to be doing... and are not... to our planes.
Click to expand...


Seems to me you have a history of picking questionable A&P's. Do you shop based on price? I ask that based upon your other post where you bemoan prices on anything aviation related.
 
You can only safely/easily track your prop with the spark plugs removed...do it when doing a compression test...not a bad idea to dress and touch up with plugs removed as well.
 
Doc Holliday said:
Seems to me you have a history of picking questionable A&P's. Do you shop based on price? I ask that based upon your other post where you bemoan prices on anything aviation related.
Click to expand...

Seems to me you have a history of always posting negative comments to anything I post.

No matter, I'll keep posting and you can keep finding fault. Let's see who helps other pilots the most, OK?

When I find an AP that is worth the money he charges, I'll let you know. So far, they all have slipped up someplace and, had I not done the research on my own, it could have been my neck.

I strongly urge others out there to not take their mechanics at face value. They're human, they make mistakes or miss things they should not.
 
OneCharlieTango said:
Maybe you’re an A&P. Or maybe you have an experimental airplane. If not, you might think about removing a post in which you confess to non-approved owner-performed maintenance.
Click to expand...

Page 8-7 of the POH for my Cessna 150M: "Pilot Conducted Preventive Maintenance"

Page 8-13 of that same section: "Propeller Care"

Alrighty?
 
Gone Flyin said:
Seems to me you have a history of always posting negative comments to anything I post.

No matter, I'll keep posting and you can keep finding fault. Let's see who helps other pilots the most, OK?

When I find an AP that is worth the money he charges, I'll let you know. So far, they all have slipped up someplace and, had I not done the research on my own, it could have been my neck.

I strongly urge others out there to not take their mechanics at face value. They're human, they make mistakes or miss things they should not.
Click to expand...

Why not just get your own A&P certificates?
 
Gone Flyin said:
Page 8-7 of the POH for my Cessna 150M: "Pilot Conducted Preventive Maintenance"

Page 8-13 of that same section: "Propeller Care"

Alrighty?
Click to expand...

How does this apply to 14 CFR Part 43 Appendix A ?

Are you making logbook entries for your maintenance as required by 14 CFR Part 43.9?
 
My A&P-IA dresses my prop at every annual. Can't say he tracks it, but I'll start doing that at every oil change when I also check compressions and the plugs are out. I run a bare hand, then a rag over both edges at every preflight to detect nicks.

If I understand "ringing the prop" (and I may not), I do it on every preflight. There's a sweet spot (about 1/3 out from the hub) where if knocked with a knuckle, the prop "rings" like a low-tone bell. I've always assumed if it was cracked the tone would change and unless both blades were similarly cracked they would ring with different tones.
 
I make a check list for each annual inspection based on the list in the POH, and check off each item as the IA completes it, and remind him when he skips something. Remember that AC43-13 is to be used in the absence of info from the manufacturer, not as gospel.
 
My partners say our prop is dressed at every annual. I think they're using a different, much looser definition than me. I've flown 10K-hour beaters with props that look and perform better than ours.
 
Gone Flyin said:
Seems to me you have a history of always posting negative comments to anything I post.

No matter, I'll keep posting and you can keep finding fault. Let's see who helps other pilots the most, OK?

When I find an AP that is worth the money he charges, I'll let you know. So far, they all have slipped up someplace and, had I not done the research on my own, it could have been my neck.

I strongly urge others out there to not take their mechanics at face value. They're human, they make mistakes or miss things they should not.
Click to expand...
The problem is that you don't know how much you don't know.

That propeller is the most highly stressed part on the entire airplane. Centrifugal and twisting forces are awesome. If nicks aren't properly dressed out as per the prop manufacturer's service manual or AC43.13, you can make things much worse. If that thing cracks and flings a chunk of blade, the imbalance will likely tear the engine off the airplane before you can shut it down, and when a few hundred pounds of engine falls off the nose, what happens to the CG? The airplane won't even glide. You start dressing the blades close to the hub and you're really asking for trouble. That prop is so highly stressed that the manufacturers have overspeed limits. Here's a typical requirement from MCCauley:

upload_2021-8-10_11-58-39.png

Look at that. It should tell you something. A 15% overspeed puts an additional 32% of centrifugal force on that prop, and it could now be deformed or cracked. Compare that to the airplane's airframe that is stressed for 3.8G (280% overload) with an additional 1.5 safety factor above that. Or the engine mount that has to be good for 9G, 800% overload. That prop is very highly stressed. Dressing it is serious business.

Further: The propeller manufacturer publishes minimum blade thickness and width minima, and constant dressing of the prop when it doesn't need it soon takes it below the minima, and flutter and destructive vibration can occur.

You are dangerously presumptuous and you'll never admit it, or know it, until you either have a serious failure arising out of your "maintenance" or you go and study and get an A&P. The stuff you must know covers a wide range of subjects, much wider and deeper than you know. It's obvious to those of us who have the training and licenses and experience.

From https://tc.canada.ca/en/corporate-s...571-appendix-field-repair-aircraft-propellers

upload_2021-8-10_11-48-23.png

upload_2021-8-10_11-48-45.png
Those are limits typically published by prop manufacturers. Look at the limit numbers in the first diagram, and where on the blade they apply. Then note the right and wrong ways to do the dressing. There are a lot of ways to do it wrong, and very few to do it right. You get it wrong and you might die.
 
Gone Flyin said:
Page 8-7 of the POH for my Cessna 150M: "Pilot Conducted Preventive Maintenance", Page 8-13 of that same section: "Propeller Care"
Click to expand...
Problem is your POH doesn't meet the requirements for Part 43.13(a) which governs your ability to perform your preventative maintenance. Now there are some vendor documents from prop mfg'r that do fall under Part 43.13(a) that give certain prevent mx tasks that can be performed by a pilot like paint touch up, etc. but the unapproved sections of a POH/AFM are not one of them. When you sign off your prop work do you reference the POH?
 
14 CFR part 43 appendix d does not require prop tracking as part of a 100 hr/annual inspection. It’s optional.

(h) Each person performing an annual or 100-hour inspection shall inspect (where applicable) the following components of the propeller group:

(1) Propeller assembly - for cracks, nicks, binds, and oil leakage.

(2) Bolts - for improper torquing and lack of safetying.

(3) Anti-icing devices - for improper operations and obvious defects.

(4) Control mechanisms - for improper operation, insecure mounting, and restricted travel.
 
My A&P does check my prop every annual and logs it in the Prop Log. I think I am on a 3 or 4 year dynamic balance cycle on the prop, or every time it is removed. I understand some do a dynamic balance every annual but to me that it an unnecessary expense.
 
Jumpmaster said:
My A&P does check my prop every annual and logs it in the Prop Log. I think I am on a 3 or 4 year dynamic balance cycle on the prop, or every time it is removed. I understand some do a dynamic balance every annual but to me that it an unnecessary expense.
Click to expand...

If the prop/spinner/backplate are indexed then there should be no reason to balance at every annual.
 
I’m sure there are a lot of folks that have dressed out nicks illegally.

Both certificated and non-certificated people do so due to lack of information.

Every propeller has a Blade Drawing that illustrates Minimum Blade Chord at

multiple stations.

So if the last Tech put the Prop at the limit then you dressed out another

.005 in a Paperweight is born.
 
How many accidents have been caused propeller failure, especially propeller failure with a suspected cause of improper propeller nick dressing? Does anyone actually know? If there has not been a case in the last 10 years that is suspected, it is probably not a big enough issue to worry about?

I showed a small spot/nick to my mechanic (professional AP/IA of 40 years) and he said if he had to dress out every one that size, no plane at that airport would ever fly. I live at a grass airport so my propeller gets more than its share of abrasion/erosion, but surprisingly few actual nicks requiring repair.

McCauley has this stance towards erosion "Erosion caused by sand, water, etc. that does not create sharp stress riser type damage does not need to be repaired in the field."
 
Matthew Rogers said:
How many accidents have been caused propeller failure, especially propeller failure with a suspected cause of improper propeller nick dressing? Does anyone actually know? If there has not been a case in the last 10 years that is suspected, it is probably not a big enough issue to worry about?

I showed a small spot/nick to my mechanic (professional AP/IA of 40 years) and he said if he had to dress out every one that size, no plane at that airport would ever fly. I live at a grass airport so my propeller gets more than its share of abrasion/erosion, but surprisingly few actual nicks requiring repair.

McCauley has this stance towards erosion "Erosion caused by sand, water, etc. that does not create sharp stress riser type damage does not need to be repaired in the field."
Click to expand...
Here's a previous thread: https://www.pilotsofamerica.com/com...our-propeller-has-a-structural-failure.89579/

There are several prop failures mentioned there, but this one is interesting: https://www.ntsb.gov/_layouts/ntsb....ev_id=20060720X00975&ntsbno=NYC06IA143&akey=1

This article explains the problem: https://www.aviationsafetymagazine.com/features/propeller-suicide/

Failures are rare but they do happen. Just like engine fires are rare but they do happen, so we look after flammable fluid lines and exhaust systems if we want to avoid a fire. Running out of oil is rare but we check the oil, don't we? Wings coming off are rare but they get inspected at annual. Or they're supposed to get inspected. There are ADs that mandate special wing and spar inspections even though failures are rare.

Somewhere on the 'net is a picture of a Cardinal, I think it was, that had several inches of prop blade gone. The engine had torn the top mounts out of the firewall and was resting on the nosewheel. Close one, that. 30 years ago I read of a 185 in South America that lost a prop blade in flight (CS prop hub failure) and the engine instantly tore off its mount (bed mount) and turned 90° sideways but stayed sitting on the mount. When it pulled free it pulled the mixture to ICO before the pilot could react. It was at night, over remote country, and the pilot saw a field in the moonlight and landed without any further damage. Amazing.

I don't think any of us here care to be a statistical outlier any more than any other pilot.

Edit: Found another good example. Good pictures with it, including one of a broken engine mount leg. http://www.kathrynsreport.com/2020/06/parts-separation-from-aircraft-cessna.html

One more. An article by a fellow who knows personally two pilots that have had prop failures: https://reviewbeforeflight.com/2015/06/08/tbd/
 
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