Ewfflyer

Currently flying as a contract pilot on a C421C. Nice plane overall, one engine is fresh, other is within 80hrs of TBO. Annual was done in Nov 13'.

I'm trying to stay distant from managing this plane because frankly i just don't have the time, but I want to make sure I'm flying it safe and making the proper calls on required Mx. I am also going to consult with the home base service(also a former employer of mine, great relationship) who deals more with lycomings.

First question, RAM calls for oil changes at 25hrs, max of 50hr intervals. If your company has one, I would like to know what interval you use, and any other pertinent information.

Secondly, the soon to be out of time engine. Who out there has experience running the mighty GTSIO past TBO and any specifics to really watch for besides the obvious oil consumption and samples.

Any other gotcha's to really keep an eye on?

I want to be efficient, fair, and cost conscious, but the fact of the matter, none of it matters if something goes awry.

Thanks in advance

Yoda2

You know the engines are not Lycoming's right? The Continental GTSIO's sometimes get a bad rap; mostly undeserved. I recommend always following the manufacturers instructions/recommendations or those pertaining to the STC, Etc. whatever takes precedence. Even an oil change interval can be interpreted as being part of the instructions for continued airworthiness, which is a legality... Do not run those engines over TBO, EVER! (regardless of how good the compressions and other vitals seem to be)

Turboprop

you can always call Jeff at ::: - ::: Air Impressions, INC. - Cessna Parts ::: - :::

jonnyjetprop

If you're willing to spend $65, I'd join The Twin Cessna Flyer Supporting the Owners of Twin Cessna Aircraft Worldwide

The guy who runs it ran his own C-421C on charters. He'd be a wealth of knowledge.

Ewfflyer

Thanks, I will check into those links.

Yoda not to be a jerk, but I stated the shop i used to work with deals mainly with lycomings(sell and maintain Piper products), hence I was seeking outside knowledge......

You make the statement that they have a undeserved bad rap....but then say don't run them past TBO. Do you have direct operational experience to back this up?

Yoda2

Didn't mean for it to be taken that way... Anyhow; while not claiming to be any sort of expert, yes I have flown all models of 421 and maintained them (As an A&P) but that experience is relatively ancient. The reason I stated don't run them past TBO is that they have a relatively low TBO for a reason and tend to have issues like reliability... especially if run hard with high time. Basically you don't want to be stretching a GTSIO much over TBO like you might get away with operating say an O-470 or such. Sure you want to save the boss money, though with the high time GTSIO I'd just tell, not ask, the boss to get out their checkbook and order a factory Reman... The bad raps are normally from ham handed pilots or cheap owners not maintaining the engines properly or trying to run past TBO. The reduction gears (prop shaft) don't last as long as one might hope either, without becoming out of tolerance. The 421C especially the later w/trailing link mains is a great airplane. Just be nice to the engines; maintain them and don't run them over TBO, at least not by much...

PerfInit

I have a lot of CE-300/400 series time in my former life. An operator I flew for (granted it was 20 years ago) engines routinely made it to TBO (even on the 421 motors) by using the following techniques:

1. Allow for proper warm up time (oil temp bottom of green minimum before takeoff power).

2. Don't run them too hard. We planned for cruise at 30" MP and 180kts, mixtures on the rich side of peak EGT. (Building flight time anyway right?). Watch the CHT's closely in the climb too (especially summertime)...

3. Absolutely avoid shock cooling as much as possible. Plan your descents for 1" MP reduction per minute to arrive at pattern altitude 5nm from the airport at appx 22" MP.

4. Avoid long taxi at less than 1000 RPM (the famous GTSIO gear slap). The trade off here unfortunately is premature brake wear.

5. After landing, start a timer for 3 minutes (turbo spool/cool down).

Above all, follow the RAM recommendations for engine operation and maintenance.

V/R

Yoda2

Thank you Perfinit. I wanted to tell him all that too but it just wasn't coming back to me... I'd sure think about planning for a new engine though. Yoda2

JohnnyG

These planes are great for what they were, but are becoming less and less desirable.

Owners still want 300K for nice ones, and 3 operators I know that fly a lot are averaging an engine failure a year. Suddenly a 600K dollar King Air that you spend 30K a year in mx on doesn't seem that bad, especially when you climb at 400FPM in the summer in a 400 series piston plane.

100K dollar annuals seem to be not uncommon on 421s.

Ewfflyer

Thanks again. I got the operational side of it down. Back 10yrs ago I got to right seat with an operation that operated some "b"s on a 135 and seemed to have good success, but I don't believe they are going anymore as their website has expired.

That is the first time I've heard about low rpm on taxi with the gear slap. I do take my sweet time on taxi in for the cool down and rest the digital timer for that, just as I do with any turbo'd plane i fly(mainly the pa46 series, t310r, pa34, etc...), but in conjunction with that, if you lean the engine I noticed it didn't have that "jerky" sound to it on the way in, and could use less power. I will experiment with this further.

I have been flying the following power settings. Cruise climb of 35"/1900rpm with IAS at 130-140, then 30"/1700rpm at FF around 21gph, and max TIT of 1550. CHT's are below 300 so far, but we are in the middle of the winter, and know that is subject to change. Appx 12-15 minutes out, 1"/min power reduction max, and I will get to 20" in the pattern. Most times i get my arrivals on a nice downhill to keep speed up and power reduced to final app settings. Sometimes I will drop a few inches earlier if it's choppy or excessive speed buildup is foreseen. I got worked over going into MDW last week because they slowed me down, then wanted speed back and gave them the good ole "unable"

Still no one on the oil change interval yet?