172 trainer hangar

One of the world's most popular trainer aircraft
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Apexpilot
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Posts: 50
Joined: 29 Dec 2013, 04:48
Location: Switzerland

172 trainer hangar

Post by Apexpilot »

Hello everybody!

I thought about opening a new topic concerning all hangar issues related to the Cessna 172. A new topic for pilots who want to understand their aircraft in every detail as if it really was their real airplane on the nearby airfield.

I am simulating "My Private Cessna 172" on FSX and try to calculate as accurately as possible, how expensive it would/could get, if i wanted to purchase one of these treats in my future live. But to do this "professionally", i have to know and understand all the facts around maintenance.

So, there is my first question :)

- After my last flight from Skagit to Felts, i got alerted by the message, that some oil is leaking from the oil lines but i do not really know why this is happening. Wrong viscosity maybe? I am using 20W-50 combined with the CamGuard additive.
The temperatures during the last days or weeks where tumbling between 10°C (50°F) and 21°C (70°F). So, nothing unusua. I fly with a reduced power setting during cruise flights and try to fly with approximately 2300RPM. Oil Pressure and Temp are always well in the green arc.

I guess there are Pilots out there who can help me out with their technical knowledge! :)

Thanks in advance guys!

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AKar
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Joined: 26 May 2013, 05:03

Re: 172 trainer hangar

Post by AKar »

I had an oil leak with my Cessna as well. It was detectable in preflight due to suspiciously high oil consumption, but I accidentally clicked up the maintenance hangar which confirmed the leak before I had time to follow the oil consumption enough to convince me that something was wrong. :)

20W-50 can be used all the time, basically regardless of temperature. If you loose oil from the oil lines, there are not many ways how the way the airplane was operated by pilot reasonably could have contributed to that (at least coming to my mind). Sometimes the lines just may develop leaks, causes typically being poor installation or degradation of the material. If you are interested in details of your airplane, the recommended maintenance work and inspections concerning the oil systems are basically as follows.

Oil and oil filter
  • Replace the oil and filter and inspect for metal content every 50 hours or four months (Lycoming SB480)
Oil cooler
  • Check for condition and security every 50 hours
Engine overall
  • Check for sings of oil (and fuel leakage) every 50 hours, and wash the engine
Oil hoses and lines
  • Check for leaks and proper installation without chafing or abrasions every 50 hours
Crankcase, oil sump, accessory section
  • Check for cracks and oil leakage etc., and the breather lines for obstructions every 100 hours
Oil filter tube
  • Check should there be any signs of contact with the engine mount every 50 hours (Cessna SB99-71-02)
Oil Pressure Switch (p/n 83278)
  • Replace every 3000 hours (airworthiness limitation!)
...and specifically:

Engine compartment flexible fluid-carrying hoses (except drain hoses)
  • Replace every 10 years or at the engine overhaul

So, actually there is not that much maintenance that needs to be done, much is done 'on condition'. In real life, planes show leaks, cracks, corrosion and other issues that just need to be taken care of, and often they just cannot be said to be caused by the pilot. Actual maintenance expenses vary, much depends on your maintenance shop (and perhaps your CAMO too, if in Europe), and on pure luck too! :) Some individual planes are more bitchy than the other ones.


-Esa

Apexpilot
Airman First Class
Posts: 50
Joined: 29 Dec 2013, 04:48
Location: Switzerland

Re: 172 trainer hangar

Post by Apexpilot »

Awesome answer!

Thank you very much! Highly appreciated!

Yes, i am based in Europe (But on the FSX i am flying most of the time in the Northwest US and Canada, Europe is okey if you head east, there you can still enjoy some aviation liberty. Otherwise, it is cramped from bottom (surface) up to the International Space Station. :-P ) but i do not plan to give "my airplane" to a flight school, so i don't need a CAMO.
But it is nice to hear that the A2A Cessna is like a real aircraft and the pilot is not always the guy who is responsible for wrecking the plane down. As in reality the stuff around me just wrecks itself :D

Thanks again mate! In this case i will let her leak until the next 50 hour inspection.

Best regards from Zurich (Switzerland)



(By the way - CAMO probably is forcing EU aviation in a dramatic direction. It makes flying even more expensive as it is already. Overhaul of the landing gear hydraulic hoses, turbocharger, new seat belts and magnetos on a Cessna T210L resulted in a bill of approximately 51'000$. - So, you should avoid CAMO if possible. If you are operating private, you just have to keep things 'on condition' ;-) )

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AKar
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Joined: 26 May 2013, 05:03

Re: 172 trainer hangar

Post by AKar »

You're welcome! And you mostly fly in Orbx North America too in sim, I see? :)
Apexpilot wrote:Thanks again mate! In this case i will let her leak until the next 50 hour inspection.
That's what I do! For realism, I try to visit the maintenance hangar only every ~25 hours (as my planes get relatively little flight time in hours) to change the oil and check other stuff. Only if I noticed something in preflight, or suspect any issue otherwise, I may take an unscheduled maintenance hangar stop. That way I need to have a feeling of how quickly the oil is consumed for example to suspect an oil leak.

Actually, this is one of the top small items on my A2A wish list - to have a button in the hangar that shows the airplane issues. "Inspect airplane" or similar. Otherwise they should remain hidden. The recent removal of automatic plug cleaning and battery charging, giving them clickable prompts instead, is already a great improvement for a purist like me.
Apexpilot wrote:But it is nice to hear that the A2A Cessna is like a real aircraft and the pilot is not always the guy who is responsible for wrecking the plane down. As in reality the stuff around me just wrecks itself :D
I've noticed that to get best out of the simulation, I can select an used airplane and then repair everything that shows up. Perhaps even overhaul the engine. That quite nicely simulates that you bought an airplane straight from large maintenance (as they are often sold in real life due to receiving the maintenance bill :mrgreen: ), but still having more variance than in 0.0 hour plane.


* * * * * * * * *

Apexpilot wrote:(By the way - CAMO probably is forcing EU aviation in a dramatic direction. It makes flying even more expensive as it is already. Overhaul of the landing gear hydraulic hoses, turbocharger, new seat belts and magnetos on a Cessna T210L resulted in a bill of approximately 51'000$. - So, you should avoid CAMO if possible. If you are operating private, you just have to keep things 'on condition' ;-) )
This is a subject of which I could yap on forever. :)

I understand that there are new more practical regulations in the workings at EASA, so it could change a little. But even in the current system, I really don't see the CAMO as the problem, nor the regulations themselves for most part (as poorly written as they are!). The problem rises from arbitrary interpretation of what are the acceptable standards. In principle, there is not much difference whether you've got CAMO services or not. Actually, the regulations are so that you can save some €€€s in airworthiness review costs if the plane has been in 'controlled environment', basically meaning under CAMO's supervision (another ridiculous concept basically removing all the independent supervision of the airplane's airworthiness, but let's not get there!).

The basic concept in continuing airworthiness as in EASA is that the owner of the aircraft is responsible for all that. Period. The only two exceptions are 1) that the aircraft is leased to an operator, and the responsibility for continuing airworthiness is explicitly noted to be transferred, and/or 2) an approved CAMO, or Continuing Airworthiness Management Organisation, is contracted to take care of that.

For the aircraft to remain airworthy, there is no difference in principle on what needs to be complied with: in either case, the ADs need to be complied with, ARC needs to be current and the aircraft needs to be maintained in accordance with its approved maintenance programme, written either by the owner or by the CAMO, and to approved maintenance standards using approved maintenance data and approved, traceable parts.

But what you "really" need to do, depends basically on what the local authority requires. And that depends, in turn, of in which country you are, who you are, are you a CAMO or private, are you a big player, your face factor, do you fish with the officials ... whatever. They are just people too, and the regulations/AMCs are written, and especially interpreted, so that there is much space for arbitrary ruling. Even while all the players, in principle, comply with the same set of rules!!



Why I think the system is seriously flawed? Let me give an example. You mentioned the Cessna T210. Let's say you bought one, and contracted a CAMO to make and keep it airworthy. The CAMO creates a maintenance programme, based on SM/AMM, SBs, ADs etc. Then it runs through the maintenance records. Now, for the aircraft to be airworthy, for each task that the maintenance programme, or any AD, requires, there must be a signed CRS that shows that it has been complied in its due time.

Now, the CAMO finds that the landing gear hydraulic hoses and magnetos are overdue, and for the seat belts, that were changed in time, it can't find a Form 1 or equivalent (FAA 8130-3 for example). The turbocharger has been 'repaired', but no relevant maintenance data is referred into, and its S/N matched an AD with no statement on its release sign-off whatsoever concerning that. As a CAMO, you've got no other option to order that maintenance to be performed. One lucky aircraft owner to who you'll tell that it takes about 50.000 to make your new airplane flyable again. Also, all the relevant detective work takes tens of work hours, for which you can never invoice the amounts that it would need to make it profitable, from private operator. Probably the private operator, if he kept the airworthiness management with himself, would just ignore these findings for the time being, sleeping well as he thinks that these are just minor paperwork issues (ignorance is bliss!), or make some patch-ups that no one would likely never find out. Or if someone did, they would likely be ignored anyway.

For the CAMO to provide good customer service, they must work similarly - that is, they must work more unprofessionally! As it is customer's primary interest to pay less. But doing so, these businesses assume responsibility, and the CAA who knows just as well how the game goes just reserves the right to... well, supervise you, while holding your organisation approval, should they get angry at you for some reason.

The EASA has created an environment in which the CAMOs, as businesses, have economical, moral and juridical responsibilities - and all three are conflicting with each other!

-Esa

Apexpilot
Airman First Class
Posts: 50
Joined: 29 Dec 2013, 04:48
Location: Switzerland

Re: 172 trainer hangar

Post by Apexpilot »

Hello Again! Thanks for the extensive reply :)

By the way, i decided to visit the maintenance shop on Flets Field. After a approximately two hours flight from Skagit, i last more then one quart of 20W-50 Oil and the next inspection was more then ten hours away. I guess, it is a good reason to pay a mechanic ;)

Best wishes from Switzerland!

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AKar
A2A Master Mechanic
Posts: 5239
Joined: 26 May 2013, 05:03

Re: 172 trainer hangar

Post by AKar »

No problem, thank you for discussion! :)

Yes, that kind of oil consumption is clearly excessive. For the Lycoming IO-360-L2A/160 hp, the oil consumption limitations are:
0.52 qts/h at rated power/2400 rpm;
0.39 qts/h at 75 % cruise power/2180 rpm;
0.34 qts/h at 65 % cruise power/2080 rpm.

From conversations with people that have years of practical experience with Lycoming and Continental airplane engines, I can say that an engine without immediately obvious problem practically never even approaches these numbers. Even with piston rings with gaps aligned you won't usually get that kind of figures. The exact consumption varies from engine to engine, and some are known for their thirst. But those come clearly short from the limit figure. Typical figures may be something like 0.1-0.2 qts/h for many engines (note the 100% difference in between the figures!). Therefore it is more important to know your engine, and monitor the 'trend' of oil consumption for sudden changes than to blindly monitor it for the written limits.

-Esa

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