Progressive inspection (50hour) for Cessna172S at my acdademy

[John777]

As far as I know about the progressive inspection at my academy, they use 50 hour interval and
each phase consisted of a detailed inspection of part of the aircraft and a less intensive check of some other systems. When I look at the clipboard for particular tail number, I see inspection due date for 50 hour, 100 hour, and annual.
I understand for a high use airplane it make sense to do the inspection every often and spread out everything so each airplane inspection takes less time, thereby eliminating time consuming at 100 hour inspection.

Now my question is, if we do two phases of 50 hour inspection, why do we still have to go through the 100 hour inspection? Is this because they look at different part of the AC during each phase of the 50hour inspection and remaining parts during 100 hour?

Can somebody provide with example please?

Thanks.

John.

 

[arnoha]

I can tell you that my aircraft, which is on the line with a school, goes through a 50-hr and 100-hr.

The 50-hr is pretty minor, little more than an oil change. It runs a bit under $400 and the plane is down for an afternoon.

The 100-hr isn't far off from an annual. It runs $1300 and 12 hours, so it's down for two days, best case.

The annual replaces one 100-hour for $1500. That's 2-3 days.

 

[John777]

I can tell you that my aircraft, which is on the line with a school, goes through a 50-hr and 100-hr.

The 50-hr is pretty minor, little more than an oil change. It runs a bit under $400 and the plane is down for an afternoon.

The 100-hr isn't far off from an annual. It runs $1300 and 12 hours, so it's down for two days, best case.

The annual replaces one 100-hour for $1500. That's 2-3 days.

Since 50hour is not regulatory, can we skip it and fly beyond 50hour inspection due?
Also, from your example, are you doing 2 phases of 50hour inspection and then 100hour or just one phase of 50hour and then 100hour?

 

[arnoha]

Since 50hour is not regulatory, can we skip it and fly beyond 50hour inspection due?
Also, from your example, are you doing 2 phases of 50hour inspection and then 100hour or just one phase of 50hour and then 100hour?

The 50-hour comes every 100 hours since the 100-hour includes an oil change. So I guess it's a bit weirdly named!

My understanding is that the 50-hour can be skipped. But you can't skip the oil change reasonably, so it doesn't buy you much to skip it. Most of the cost is the oil change. I believe oil analysis is done on my engine every other oil change with the 100-hour.

 

[John777]

The 50-hour comes every 100 hours since the 100-hour includes an oil change. So I guess it's a bit weirdly named!

My understanding is that the 50-hour can be skipped. But you can't skip the oil change reasonably, so it doesn't buy you much to skip it. Most of the cost is the oil change. I believe oil analysis is done on my engine every other oil change with the 100-hour.

I see, so the inspection will be this way:-

1)50hour
2)100hour
3)50hour.. and so on...

 

[John777]

I see, so the inspection will be this way:-

1)50hour
2)100hour
3)50hour.. and so on...

"But you can't skip the oil change reasonably, so it doesn't buy you much to skip it"

can you rephrase it? I am having hard time understanding here...

 

[flyingron]

First off, you have to explain what you mean. Is this some schedule they put themselves on or are they on an FAA-approved progressive inspection schedule.
In the latter, the approval will spell out what is optional and what can be time deferred. Chances are, as with the 100 hour, your extension is limited to getting the plane to the maintenance shop.

There's no obligatory requirement to change oil at all during an annual. It's just commonly done there because most people defer MAINTENANCE to the annual INSPECTION.

100 hours have the same scope as annuals other than the fact they can be performed by A&Ps. Our old club used to have them all signed off as annuals anyhow.

There are some things, like the ELT check (and some ADs), which have to be done annually, but aren't part of the "annual inspection". You could do them at any time each year, but most people do them at annual.

 

[mondtster]

There are some things, like the ELT check (and some ADs), which have to be done annually, but aren't part of the "annual inspection". You could do them at any time each year, but most people do them at annual.

Ron pretty much nailed it. I would offer one point of clarification on the AD part however. There may be ADs due every 50 hours (or due even more frequently) which would necessitate that the inspection be done on time.

 

[Dan Thomas]

Cessna publishes a couple of different maintenance schedules for their airplanes. They have the typical 50-100-50-200 hour cycle, and the progressive care inspection that has four phases. The first will be a 50-hour where the oil and filter get changed, some stuff inspected on the engine, and the fuselage equipment, for example. The second will have the same oil and filter change and the landing gear. The third will do the same oil and filter and maybe the sparkplugs, and the tail and aft fuselage. The fourth will cover the engine more extensively and the wings.

This is only a general idea. The four inspections are more detailed than that, but you get the idea. The intent is that the entire airplane gets inspected at least once in 200 hours, with the more critical stuff inspected every 100 r 50 hours. It's supposed to reduce the big downtime when a 200-hour inspection requires the opening up of everything, removal of the interior, and so on. Commercial operators often prefer it so they can keep the airplane busier. It makes sense where the airplane flies many hundreds of hours per year.

 

[GlennAB1]

The progressive Inspections I've been involved with, during each "phase" the whole aircraft gets a general inspection (GVI), or cursory (a Boeing term).

Detailed inspections are broken up so that specific areas get an intensified inspection (basically, annually).

Yeah, it's supposed to reduce down time, that's questionable, maybe it does when an aircraft is new....

 

[Tom-D]

If your following the service manuals of Cessna aircraft you will be on a 25/50/75/100 hour schedule. that does not relieve you the responsibility of the annual every 12 calendar months
the Progressive schedule is what ever the FSDO that approved the schedule says it is. this will relieve the required annual.

Do not confuse the progressive inspection for aircraft in the GA fleet with the scheduled maintenance of the Part 121 and 125 operators

 

[Dan Thomas]

If your following the service manuals of Cessna aircraft you will be on a 25/50/75/100 hour schedule. that does not relieve you the responsibility of the annual every 12 calendar months
the Progressive schedule is what ever the FSDO that approved the schedule says it is. this will relieve the required annual.

Do not confuse the progressive inspection for aircraft in the GA fleet with the scheduled maintenance of the Part 121 and 125 operators

Never seen a 25-50-75-100 hour inspection cycle for a Cessna. And I work for a Cessna dealer.

They're 50-100-50-200 cycles.

 

[Tom-D]

Never seen a 25-50-75-100 hour inspection cycle for a Cessna. And I work for a Cessna dealer.

They're 50-100-50-200 cycles.

Yer right for the later models like the 172 service manuals, but 1962 and prior 100 service manuals section 2 page 13 gives a service integral of daily / 25 /50/&100 so it's a matter of which book you are looking at

 

[arnoha]

"But you can't skip the oil change reasonably, so it doesn't buy you much to skip it"

can you rephrase it? I am having hard time understanding here...

Most of the other post have given a more nuanced answer, but to try again on that statement...

Going longer than 50 hours between oil changes is not something that would be recommended. So, the plane is going into the shop at 50 hours, no matter what. Turning it into a 50-hour inspection adds little to the price tag (around $50), since the inspection is pretty basic. It's not regulatory to do a 50-hour inspection at all, but it's generally done anyway because it's cheap and easy. And...having that sort of structure is often either mandated by the insurance company or reduces rates, so it ends up financially smart to do it in a commercial environment.