annual inspection - questions

[office_supply]

An annual was completed on an aircraft and a few questions have come up. The sort which I'd prefer to ask here. Following is a list of items, that were stated completed, but either were not done, or something else. Is this normal "practice"?

1. An oil change is stated as being carried out, but none was done.
2. Compass swung - all numbers the same as previous annual. What are the odds of that?
3. Of five AWDs (due every 100hrs) only two are stated as being completed
4. A compression test was done, but the exact numbers were not recorded. 3 of 4 numbers written down were taken from previous compression test
5. tachometer accuracy check carried out, when I received the plane from the annual, tach cable wasnt even attached to the gauge.

Comments or advice? Am I being shafted here?

Thanks,
office_supply

[Hedley]

There is a LOT of context missing here ... but
I might mention some thoughts:

1) AD's are NOT the mechanic's responsibility,
they are YOURS. A 100hr/annual inspection
can legally be signed off with AD's outstanding
because they are YOUR responsibility for
compliance, not his.

2) did you search around for the cheapest
possible annual? If so, it looks like you got
what you paid for. If you paid $500 for this
annual, you got your money's worth. If you
paid $15,000 for this annual, consider a new
mechanic.

3) I really, really recommend owner-assisted
annuals on private aircraft. Most of the items
on an annual/100hr inspection are elementary
maintenance, fer crissakes. You do not need a
Phd to r&r inspection plates or clean spark plugs.
You need to get your hands dirty.

4) don't confuse paper with metal. You
can have a legally airworthy aircraft which is
mechanically a mess. You can have a fine
aircraft with no paper. You need to keep
both loosely-coupled worlds (paper and
metal) happy. Understand?

5) There are some thief AMEs, and some
thief pilots. I've met both. From this distance
it's difficult to tell which is which in this
case (if any).

6) Many AMEs refuse to work on private
aircraft, and with good reason.

[qa guy]

Maybe it's time to find another AMO/AME. But ask him first!
(You know what they say about assuming) There may be a reasonable explanation for each of your concerns.
However, there are many freelancers out there that could not properly carry out a compass swing.......sad to say.

[Bulawrench]

I agree with these fellows. That is one of the worst cases that i have herd. If i was you i would stop payment on that check. The Owner can get involve like Hedley suggests but the first time you have a plug come out at altitude you may change your mind on that one.

[office_supply]

Thanks for the replies;

Hedley, as I understand it, checking which AD's apply to an aircraft is owner responsibility, but actually performing the AD, is up to the mechanic. Am I wrong? Could you clarify? Should I state next time exactly which ADs the mechanic should work on? I guess I assumed he'd know the ADs from looking at previous annual entries in the logbook. As it stands, I have ADs which will run out before next annual (in terms of hours) what is the procedure then? Have it go in just to check the ADs?

As for my mechanic selection, the answer was simple. The one closest to my home base. I did not shop around. The annual itself cost me 800 dollars, but it didnt factor in parts (obviously) nor did it factor in labour. For instance, work was performed on the landing gear at an extra 10 hours on top of the 800. In the end, my bill was near 3000 dollars. I didnt quite ask the mechanic to be cheap either, I prefer to keep the airplane healthy.

I would have loved to assist the mechanics, however partly due to working 6 days a week, I could not. As well, waiting for parts also lengthened the annual. It wasnt a weekend job unfortunately.

Hedley, your comment about paper and metal airplane, is this to mean that what was done to (for instance) compass swing and compression is ok or often done, so long as there are no major discrepancies?

office_supply

[MCRS]

Office:
Most AMO/AME's see several different Aircraft in a week, if you took the Aircraft into an AMO to have the Annual done the work is usually assigned to the person who will do the Annual. If that said person, (Experienced Apprentice, or AME) is unaware of what AD's, SB's..... Are due at the Annual
he will not complete them. Simply assuming they will be done with out stipulating which ones are to be done, just won't see very many done! (As you already know from experience!) The person working on the plane may assume (rightly or wrongly, that if it isn't requested it must have been done, doesn't apply, or owner doesn't want it done!) The guy on the floor isn't paid to look at the history of your tech logs (unless you asked them to when you brought the Aircraft in) so he isn't likely to go searching to see if they were done at the last annual, or the Annual before that. Just the nature of the business, if the AMO let every Engineer look over the Log history of each aircraft that came throught the doors, who would pay for it? You? AMO?
So to make the Statement that the AME should look at the history may be asking to much from some AMO/AME's.
I would suggest at the next annual stipulate which AD's, SB's, etc. (If any are due within the next year!) are to be dealt with at the Annual, this would preclude any missed work for you, or the other option, have the AMO/AME do the search and comply with whatever is going to be coming due within the next year. (Of the currently published AD's, SB's, etc.)
Next item, I have carried out Several compass swings on aircraft that I have seen year after year, some actually deviate very little if at all, and others require massive adjustments. Usually the ones that had to be adjusted a fair bit came as a result of Avionics work (Change configuration) Engine heaters that have had the power cord wrapped around the engine mount(Magnitized), etc.) If there has been no real work carried out to the Aircraft it could theoretically be very close or difficult to see a change to the original numbers. Your the first Pilot I have heard mention a concern over a compass, most I run into complain about even having to have a compass swing, they say why do I need this when I have my trusty GPS!
Just out of Curiosity sake how do you know the oil wasn't changed, and the compression test numbers were not numbers from this compression test but the last as you state..
I am not doubting you, especially after what you are listing as deficiences,just curious that's all.
I am in agreement with Hedley and QA as well on all the items they listed, Might be worth going in and having a talk with the AMO about what you found and see what can be arranged to fix the problems and for your peace of mind.

[SeptRepair]

Not all AD's require an engineer to sign them off. Some ad's state an owner/pilot can research the logs and see if an item has been replaced/reworked etc. The owner/pilot can then sign off the ad as having been complied with ( assuming it wasn't an item that was listed as to being something that needs attention). If in doubt ask your engineer to do it. Also some ad's are as simple as making sure a supplement is installed in the POH. If your aircraft is Canadian registered go to Transport Canada's website and search by registration number. All Ad's will come up that are applicable to your aircraft. Except of course the miscellaneous ones. which can be a long drawn out procedure if your unfamiliar with them. Like Hedley stated, it is the responsibility of the owner/operator to ensure all ad's have been complied with.
Ad's that run out before your next annual and of course are reoccurring are your responsibility to make sure get done as stated on the AD. Most ad's are usually written in such a way that they coincide with schedule inspections be it 50/100/200 hour intervals. Which AD are you specifically worried about?
As for a compass swing ( i know i will take heat for this) for the most part are a waste of time. A new installation of a compass or after rebuild should be done. Sitting in an aircraft and running at approx cruise power the thing is shaking like a dog shitting razor blades and any accuracy trying to read the thing is thrown out the window let alone trying to adjust it and take out the error. Technology has advanced considerably and most pilots have GPS and other navigational equipment installed in their aircraft, so the compass is pretty much an ornament. Legally it must be swung each year, but myself and others i know pretty much pen whip it and make up a new card.
Compression checks should be recorded by the engineer, preferably in the log book so the next guy can check and see the history of how its been operating. Some guys just write it on the rocker cover, but it isnt that hard to take the 20 secs it takes to write it in the log as well. Sometimes the numbers dont change. Perhaps this is one of those times?
Signing off the tach check and obviously having it not working sounds pretty far fetched, but i digress, there are those out there that are phucked.
Anyways, sounds like your annual is a little shady. But ill make ya a deal. send me your journey log book and for $600.00 ill sign off your annual and send it back to you. Just promise you will change the oil and clean the plugs. KIDDING!

[office_supply]

MCRS, thanks, I'll make sure to mention next time I'd like all AWDs done.

As for the oil and compression... I had the oil changed about a month prior to the (start of the) annual and asked that the oil not be changed. The oil only had about 10 hours of air time on it. I can (more or less) confirm that an oil change wasnt done due to the fact that when the plane went into annual, it only had 3qts (4-5qts nominal, 6qts max). I would (again I know shame on me) assume that during annual, an oil change would mean providing the proper amount of oil for normal flight. In this case, (usually) 5qts. I was also not charged for any oil. Given the other charges I was billed for, including screws (which I understand) Im sure I'd be billed for a few $8.50 quarts.

The compression checks, again a month prior (in fact, at the same time as the oil change) I had a test done. At the time, I had a weak cylinder and during annual spoke to the mechanics about it. I went in part way through, and the mechanic told me he did a compression check and all cylinders were good, even the one that was low. When I asked for the numbers, he told me he didnt remember them. Could be that he had them written down and didnt memorize them (which I can fully understand!) or that he did the check and didnt record/lost the sheet. Four tests has been done on the airplane in the last three years and none of them had the same numbers, except for the last two, had identical numbers except the weak cylinder.

Maybe Im just being nitty gritty. Same for the compass swing, generally the few (less than 5degrees) goes un-noticed during flight for me so it doesnt bother me, I just found it weird that two annuals in a row the compass had the same numbers, and never before that.

On that note, doesnt an outstanding AD invalidate the CofA?

SeptRepair, I'll have a better look for a complete list of ADs I had checked it previously but didnt really read in detail all the ADs. Kinda just skimmed. The two "important"? ones were pertaining to loose rivets and control cables. Again about the compass swing I do find it pretty... useless? So long as the compass isnt out of whack. I actually fly with map and compass, I have no NAV aids and I use a hand held non aviation GPS as little as possible.

office_supply

[SeptRepair]

Ah that makes a bit more sense about the oil and compressions. Was the oil change recorded at the time it was done? Or did he just sign it as being done at the annual to play a little catch up in the books?
BTW what kind of airplane do you own/operate?

[MCRS]

Office Supply:
As to the AD's depends what the requirements are on the AD, some stipulate a date time, some a specific number of hours and others have both a date and Time listed. ie 200 hours or 12 months which ever comes first. Not knowing which AD/AD's you are refering to nor the time/calender dates
listed I can't give you an answer to your question. However if you recieved the AD in the Summer at 1/2 way to your Annual and the AD said Due at the Annual well you can make the decission there.
Sorry, can't be more helpful. If you are over due there are some circumstances where you can get a permit from Transport to get the Aircraft to an AMO/AME to have the AD carried out.
The Additional information you supplied about the compressions and oil change are helpful, especially if you mentioned them to your AME when you were discussing what had recently been done. I am sure he decided that if you had changed the oil only 10 hours before he wasn't going to do it again, and like Septrepair says, if it was a missed entry in the log he may have been helping you out a bit by entering it now so as not to catch you with your pants around your Ankles if transport started snooping in your books. He may not have been to concerned about recording the compression numbers either if they came out to the same as what you found on your oil change.
Recips can be funny with the compressions to, if the rings all line up you can get a bad Cylinder reading even if it is a good Cylinder. So he might have had the rings in a better position for holding compression then you had at the last check. (I have had a couple fail, then took it for a run came back check compression again and they where reading high 70's!)
Compass swings: There are probably more shops then you carry to know that either pencil whip the cards, or use means other then a land compass for calibration of the compass. Just the way things go these days with all the GPS systems out there nowadays. Be an idea to tell the next AMO/AME you do all your navigation by Map and compass they will probably make sure the swing is done correctly then to verify all the numbers are correct. (Like I said unless you have done any work to the Aircraft it probably hasn't deviated very much, very likely less then 5 degrees.)

[office_supply]

I'd prefer to remain anonymous so all I'll say is that the aircraft is a two-seater.

The oil change was done by another shop while on vacation and I did enter it in the journey log.

All ADs are on a 100hrs basis only. At present, non are outstanding, but three of the five only have 40 hours left, whereas the others which were done at annual have 85.

MCRS, you are right about the rings. That cylinder went through many compression tests and came out weak. Starting in the 60s and ending up at 48 when the oil was changed. At annual, the mechanic told me it was back up in the mid 70s. I suppose thats better than replacing a cylinder.

office_supply

[Strega]

sounds like you have a 150,, and have been given the run around by an "engineer".

As for the ADs and who is responsible, well officially, you, as the owner, are responsible for AD compliance, but if you order the "engineer" to comply with all ADs outstanding, and he doesnt, that "engineer" is on the hook. Just keep a copy of the work request in writing.



if you want, I can give you a list of items that can be pencil whipped, and others that cannot. ie what are the bullshit paper exercises, and whats important to keep you, and your passengers but safe.

[markymarkl]

Some words of wisdoms from a 30 year vet.

Step 1. Find an AMO or AME and spend a little time getting references for them.

Step 2. Talk to other A/C owners that have had work done by them-(and not the ones that hang around the hanger and have coffee with the AME/AMO folks.

Step 3. Sit down and discuss the work that must be completed (AD's, oil, comp. test, what you want to see done) and how you would like to have this information presented to you at the end of the process ( written, verbal, email??) This will cost you a few bucks but it is worth the peace of mind that you will get and you have it in writing.

Step 4. Ask for an estimate! Most reputable AMO's can give you a ball park figure. If something major pops up ask the AMO to call you and let you know (its your $$$$$$)

Step 5. Upon completion you should be presented with a detailed bill of all work and part's used for your annual insp. If you don't get a detailed statement you didn't do Step 3, and we will most likely see you post here again next year.

I don't think you got taken you got what you ask for-- Here is my plane fix it!

My best customer is an informed one, no secrets, everything is up front and they always leave happy (In my mind any ways) LOL

If you take the above steps you will be a happy camper next annual! IMHO

[Hedley]

Some free advice:

1) get up to speed on your AD's & supporting SB's. As
the owner, you're supposed to be! Enter your aircraft
registration here:

http://www.tc.gc.ca/aviation/applicatio ... .asp?rand=

Keep in mind that Transport's "tombstone data" from MSI-26
is often quite wrong. They will have the wrong prop for an
aircraft. They will have the wrong letters after an engine,
which will change the AD list. It can be very difficult to
get them to correct this.

So, before your annual, print off the AD's for your aircraft.
Are there any new ones? Are they applicable? Are there
any old, repetitive AD's (eg cabin heat exhaust muff)?

So, TELL your AME what AD action you want him to take
during your 100hr/annual inspection. Don't just ASSUME
he will do it.

2) clean your aircraft. I know, most people think stuff
comes back grungy from the garage, but CLEAN your
aircraft. Get the gorp off the belly. It's a LOT easier
to inspect a clean aircraft. You don't want to pay your
mechanic to clean your aircraft (at least I don't think
you do).

3) bring your airframe log up to date. Make all the
daily entries and transcribe any maintenance that
you did from the journey log. Why pay your AME
to do this? Put stickies in your journey log, your
airframe log, your airframe AD list, your engine
log, your engine AD list, your prop log, your prop
AD list. Spot the pattern?

4) before the annual is started, tell your AME what
you want done - esp out of phase stuff, like compass
and ELT. Do your ELT yourself, fer crissake - it's
PERFECTLY legal! Specify AD action. Tach
check, compression check, plug clean & gap,
compass swing, oil & filter is all pretty standard.

5) an annual inspection on a basic fixed-gear
fixed-prop non-turbo single should take around
12 to 14 hours to perform. The paperwork
should take 2 to 4 hours. Basically, an annual
where there is nothing wrong (ho ho ho) is
16 hours. An hour ought to cost around $100.
$50 buys the AME, the other $50 pays for the
tools and hangar. Obviously in high-priced
cities the price goes up from there. So, a
basic annual should cost $1600.

6) 16 hours is 2 days for one guy, or 1 day
for 2 guys. Basically, they pull the engine
cowls and airframe panels. If they find anything
major broken, they should CALL YOU IMMEDIATELY
with a parts and labour estimate BEFORE COMMENCING
THE ADDITIONAL WORK. Give them your cell
phone number. Text & email work great, too.
If they're in the 21 century, they can probably
digitize and email you photos of what's broken
in minutes. NOTE TO AMEs: keep the owner
in the loop! Surprises are for xmas, not
aviation.

7) get a #2 philips screwdriver, and learn
to use it. I know you're a busy guy but
trust me, you want to learn a little about
your airplane. Stock up some #4,#6,#8
and #10 half-inch machine screws and
stainless sheet metal screws, and some
fiber washers. Money well spent.

8) get a battery charger and a hand/foot
pump. Use them.

9) the following is a link to the list of
elementary maintenance tasks that
you as the owner/operator may
perform:

http://www.tc.gc.ca/CivilAviation/Regse ... /a625a.htm

10) the following is a link to the
list of "out of phase" tasks which
are often complied with during
your annual inspection, but can
often be completely out of sync
with your annual:

http://www.tc.gc.ca/CivilAviation/Regse ... /a625c.htm

[markymarkl]

More good and constructive advice!!!!

[office_supply]

I just went through ADs applicable and actually found only 4 which apply. The fifth - which had been performed at every annual in the logs - seems not to be recursive. Three ADs state every 100hrs, and the fourth, every 1 year or 150hrs. The fifth only stated a one-time inspection within 25hrs of the AD. Strangely, I thought this AD was fairly important. I'll definitely talk to my mechanic about that one.

I do like to keep my aircraft clean. I had just returned from a vacation where I put about 25 hours of flying in a week and that coupled with a weak (48/80) cylinder left a lot of oil on the belly. I went through about 3 quarts of oil that trip.. I hadnt had the chance to clean that off. Not that I want to bash, as this isnt the mechanics' fault but more his ... apprentice? Or junior mechanic, who left me wonderful boot prints on my seats though easy to clean, and a Tim Hortons' bag with a muffin wrapper in the back of the cockpit Im looking forward to the warmer weather so I can clean and polish the plane.

I keep the journey log up to date, though I dont mean what you meant by putting stickies..

I'll make sure to specify exactly what I want done next time, AD numbers, compass swing, etc etc. What on the ELT can I do myself?

As an added question, would removal of wheel fairings (and similar request) fall into an annual inspection or would that request come in as extra labor?

I do have a #2 (in fact two of them); one in the plane, one in my kit, ready for action. I had the opportunity to assist an AME in minor repair to the plane during the summer. It was a great experience.

Thanks again for the links and the help

office_supply

PS: I hope to be posting again next year. With perhaps better stories.

[Hedley]

What on the ELT can I do myself?

ok. CAR 625 app C says that every year, you must have
the ELT re-certified (and probably battery change every
other year, too). So, as elementary maintenance, you
as the owner/operator of a small private aircraft can
remove the ELT, placard the dash, and make the journey
log entry, and take the ELT to the avionics shop for
re-cert. Fly the aircraft normally. When the ELT is
ready (they may have to back-order batteries) you
pick the ELT up from the shop with a "green tag"
aka maintenance release. Re-install the ELT, remove
the placard from the dash, make the entry in the
journey log, and staple the green tag into the
airframe log.

It's not rocket science. Really. And you can
save yourself some money by doing it yourself.

Ok, I'm gonna say this once:

The first time you perform any maintenance
task on an aircraft, be sure you're doing it right
by getting someone to check you out

It doesn't matter if it's legally required or
not, get some training on your elementary
maintenance. You would be foolish not to.

removal of wheel fairings

Is that part of a low-cost basic annual? I
would say no. If your mechanic wants
them off (and he may NOT) why not remove
them yourself?

Small rant here: why on earth do people
repack wheel bearings ever year? The
aircraft may have only flown ONE hour,
but the bearings gotta get repacked

For an annual inspection, your mechanic
must check the condition and pressure
of your tires, and the brake pad wear,
all of which can be performed with the
wheel pants on. Only if you wish to
change a tire/tube/brake pad/repack
the bearings, must the wheel pants
come off.

[tired of the ground]

Hedley, Lots of great advice there.

The only thing I would like to add would be about the cleaning. Why not ask the AME not to clean the aircraft and do it yourself afterwards. I'm sure you know a bunch of outside visual clues give indications to faults that you may not otherwise see.

[office_supply]

Ah I see what you mean by doing the ELT. I had last year taken the plane to a shop, but needed the altimeter and transponder done at the same time so that kinda grounded the plane due to the altimeter being pulled out.

I also remember to put the switch in 'off'

The wheel pants was.. well only the nose gear. But that one cant come off without taking the entire gear off. Great design feature! I didnt want snow and sludge to get in there and damage the fairing or the wheel.

I dug deeper into my logs and it turns out that non-repetitive AD I mentioned is repetitive by an SB. But I havent been able to find any search database on SBs as there is for ADs. Does such a database exist?

Thanks,
office_supply

[Hedley]

SB's are issued by various manufacturers, NOT
the government. The government issues AD's.

Many manufacturers make their SB's available
online. Others do not. Google is your friend.
For example, here is some Lycoming info:

http://www.lycoming.textron.com/support ... /index.jsp

Teledyne Continental:

http://www.tcmlink.com/serviceBulletins/index.cfm

Cessna:

http://customer.cessna.com/se/faq.chtml#15

I suggest that you print off a complete set of
applicable AD's and their supporting SB's for
your engine, airframe and prop. Put each in
a file folder, chronologically ordered. Keep it
with your tech logs. Update them as new
AD's are issued. Feel free to make notes
in the margins (or use hi-liter) of the AD's
or SB's so when someone asks you whether
or not AD XYZ or SB 123 is applicable to your
airplane, and have you compiled with it,
you have some supporting documentation
to the one-line entry in your tech logs.

[office_supply]

Thanks for that, I've now confirmed all ADs and SBs for the plane. And to avoid any surprises next year, I wrote up (based on a template in the Service Manual) an annual inspection checklist for the mechanic to follow through from pre-run up to post-run up, including AD/SB checks, tach check, writing down compressions, compass swing.

office_supply

[Strega]

something to stir the pot.....


if all of the AMEs here are Engineeers,, Shouldnt they have no trouble finding, and complying with the numerous ADs on a Cessna 150? (I think there are 3 that are re-occuring, seat rails/locking mech, heater muffs, and the nutplates on the vert stab>> this may or may not be applicable)

I think its absoulute trash that TC has made the owner responsible,, most people that own small aircraft dont even know how to change the oil, needless to say search and order ADs,,


IMHO the AME should notify the owner, and write in the logbook all applicable AD's, and if at that time, the owner does not want to comply, there is a paper trail leading to the neglectful owner so the AME will not be on the hook.

[Hedley]

Shouldnt they have no trouble finding, and complying with the numerous ADs on a Cessna 150?

Ain't that simple. Let's say you're doing an annual on
a buck fifty, and you see that there is 70 hours left
until the 500hr AD is due on the impulse coupling mags.

Most private aircraft in Canada only fly 30 hours a
year, and you're busy as hell, so you don't touch it.

What you don't know is that the new owner of this
aircraft is planning several long trips in the next year,
which will exceed the 70 hours left on the mags.

Oops. Is the AME a bad guy in this situation? Well,
I think it's more a matter of communication between
the AME and the owner. Doing the impluse coupling
on a couple of mags is not cheap, and you might
not want to do them any earlier than you have to.

I agree that owners need to learn a LOT more about
AD's. I won't comment on the rules, because no
one cares what I think about them.

[office_supply]

From an owner's point of view, I find it a pain to figure out which ADs apply, and which one-time ADs have already been complied with. Especially when the log books dont go back to the birth of the plane. I'd personally like to have that responsibility handed to the AME. Oh and Im aware *some* would gladly do it.. for a sizable sum of money. I think in terms of maintaining the ADs though, as in, calculating time left on them or when to do them, should be my responsibility. Which it is.

I have to update the maintenance schedule for the plane now that I've re-checked ADs and SBs, but prior to this, all times due or dates due were maintained.

On the note of ADs though, are those labelled as recurring on an annual/100 hour basis (ie at each annual or 100hrs inspection) generally included in the "price" of an annual inspection? Provided of course, the AD only requires labour.

Im also glad I went through the Service Manual a little more carefully, I found a few extra items that have to be added. Repacking bearings was one. Curious about that one, how do you estimate "500 Wheel Miles"? I dont exactly have an odometer strapped onto the wheel hub. Is there a general amount of t/o and landings?

Thanks,
office_supply

PS: Hedley, unless it would create an AvCanada sh*tstorm, I wouldnt mind hearing your views.

[Hedley]

From an owner's point of view, I find it a pain to figure out which ADs apply, and which one-time ADs have already been complied with

um ... look at the back of the "installations and modifications" tech log.
There is a list there for airframe AD's, which should list ALL applicable
AD's for your aircraft, and whether or not they apply, and if they are
recurring. If that list is not complete, you should get it updated.

Similarly, at the back of the engine log there should be a list
of engine AD's, same as the above. Get it up to date.

Same for the prop.

So, once your AD lists are up to date, all you really have to
worry about are the new ones and the recurring ones. It's
really not that bad.

Use the Transport AD search URL!

As far as your question re: recurring AD's included in
the price of an annual, well, that's like asking how high
is up. Generally yes, but not always. For example,
the cabin heat muff inspection AD oughta be part of the
annual. Similarly, the AD on the Lyc fuel injector lines
oughta be part of the annual (if you have fuel injection).
These inspections really aren't very time consuming
or costly.

However, the 500hr recurring AD on the impluse coupling
mags is NOT part of any base annual inspection price.

This is simply something that you and your AME need
to discuss, when setting the base cost of your annual.

how do you estimate "500 Wheel Miles"?

Heh. Shot in the dark: each takeoff and landing cycle
at a small airport is probably one mile. At a large
airport, with a lot of taxiing, it might be two miles. You
know how many takeoff and landings you do, so you
do the arithmetic.