TT, CoA, Annual etc.

[MyData]

When looking through the small ads there is much about various times and dates, e.g. one aircraft at random might have:

TT Engine 1234
TT 5684
CoA due 5/9/2006
Annual Due 3/8/2006

In running your own aircraft what does this all mean?

Is TT engine relevant because after so many hours the engine has to be overhauled or completely replaced? So it gives and idea of how much 'cash' is left in the engine.

Is TT relevant simply as an indicator of the age of the airframe and interior.

Sometimes propellor TT is also given - do props have a general lifespan, or are they mandated to be changed at a certain time interval?

Now the annual and CoA.

Is the annual akin to a car's annual MoT test: checking the systems and safety aspects? How much might one typically cost for a Cessna or PA28? Is it a fixed fee + expenses for remedial work?

How does that differ from the CoA? Is the CoA issued only after a much more stringent test?

Are the annual and CoA carried out on the ground - or do they involved flight tests?

[foxmoth]

Is TT engine relevant because after so many hours the engine has to be overhauled or completely replaced? So it gives and idea of how much 'cash' is left in the engine. Pretty much correct - engines are "lifed" - usually runs to about 2,000 hours/12 years though this can be more or less, also can be run beyond this ("on condition") if not Public transport.

Is TT relevant simply as an indicator of the age of the airframe and interior. correct.

do props have a general lifespan, or are they mandated to be changed at a certain time interval? Fixed pitch run on condition but Variable pitch ones have maintainance limits on hours.

Now the annual and CoA As you say, Annual is much like the MOT and no flight test needed, CofA is 3 yearly and like an annual but more thorough and does need a flight test. You also get aircraft on PFA permits, these have an annual Permit renewal (with flight test but much can be done yourself) and no CofA.
Not so sure on prices except that a permit aircraft is a lot cheaper:ok:

[cirrus01]

Quote:
do props have a general lifespan, or are they mandated to be changed at a certain time interval?
Fixed pitch run on condition but Variable pitch ones have maintainance limits on hours
Not quite true................if you have a McCauley fixed pitch prop......they are subject of a 6 year/ 2000 Hr overhaul life ( which will cost in region of £700 ) :\

[LowNSlow]

Most Lycoming and Continental engines found in training aeroplanes like the Cessna 152 / 172 and the Piper Cherokee / Warrior have a Time Before Overhaul (TBO) of 2,000 running hours. This is usually extended by 20% to a total of 2,400 hours. Once this limit is reached then the engine can no longer be used in a Public Transport aircraft (ie; one used for flying training or rental to the public). It can however be used by a private owner "on condition". This means that every 50 hours the engine compressions are checked and the oil filter examined for metallic particles which will give (hopefully) advanced warning of excessive wear in the bearings and cylinders.

For a Public Transport aircraft the engine either has to be replaced with a new factory supplied engine or must be re-built (also known as zero timed) where all the major components of the ENGINE (not necessarily the bits and pieces like the starter, carburettor etc) are re-built to within new factory tolerances. Sometimes you will see omething like 1,200 TT s/n meaning 1,200 running hours since new or 1,200 TT s/o meaing 1,200 hours sinvce overhaul. This means you need to know how many times the engine has been zero timed as for some engines there is a limit to the number of times that they can be re-built or so I have been told in the past.

Another common abbreviation is 1,200 TOH which is 1,200 hours since a Top Overhaul which can mean a multitude of things and needs to be precisely defined by the seller. A TOH can mean that all the cylinders have been completely rebuilt or it could mean that the bores have simply been honed, new piston rings fitted and the valves lapped in or pretty much anything in between hence the need for close definition.

The new EASA C of A no longer requires a flight test as far as I know.

I found a PFA Permit aircraft no cheaper to put through an Annual than a Private C of A aircraft if all the work was done by an engineer.

[Mark 1]

every 50 hours the engine compressions are checked and the oil filter examined for metallic

I think its every 100 hours and is only a compression check unless they think it warrants deeper investigation. Some private owners have had top or bottom overhauls as required and see no real need for a full major overhaul for its own sake. I fly one that had the crank and oil pump replaced at 1000hrs for AD work and the pots replaced due to base corrosion. Still running sweet as anything at 2100hrs, possibly good for another 1000.

I found a PFA Permit aircraft no cheaper to put through an Annual than a Private C of A aircraft if all the work was done by an engineer.

Most permit aircraft are maintained on the same CAP 411 LAMS schedule as CofA aircraft, so, in principle, the same amount of work and labour cost. Considerable savings can often be made by not having to conform to a type certificate and have 'form 1' released parts. PFA inspectors are also generally happy to do the work yourself, if you are competent.

[MyData]

Thanks as always for the informative replies. I appreciate that each case is different, but what might be the typical Annual and CoA charge for, say, a C172 or PA28. Plus parts / replacements of course.