BeechTalk - BT - Aerostar vs C-421C

Username Protected · **Posted:** 31 Dec 2025, 10:41

Do you have to pull the engine to change a back cylinder on an Aerostar?

Username Protected · **Posted:** 31 Dec 2025, 11:23

I've changed a back cylinder without pulling the engine.
Its barely possible.
It might have been easier to pull the engine.

You have to do things like drill out zeus receptacles and flex some sheet metal.
(the rear zeus are now screwed down rather than riveted.)
I did this in a borrowed hanger in Alaska. (long sad story 100% my fault)

I was half way though runup in Bellingham when tower called and said your IFR clearance is available for immediate takeoff, or you can wait 45 minutes, I took off without getting the mixture full rich and cooked a cylinder on the way to PAKW.

Paul

Username Protected · **Posted:** 31 Dec 2025, 12:44

Username Protected wrote:

Do you have to pull the engine to change a back cylinder on an Aerostar?

It take about 1.5 hrs. to pull the Aerostar engine and a couple of hrs. to put it back on, so there is no need to work around it. You just pull the 5 bolts holding the engine mount to the firewall, disconnect hoses, wiring and cables and slide it forward. That being said six probe or other special wiring can double the time depending on how they are routed or attached. The good news is that Lycoming cylinders are pretty bullet proof and seldom need changing.

Best regards,
Jim

Username Protected · **Posted:** 31 Dec 2025, 13:56

Username Protected wrote:

That’s a very good point Jim. No free lunch as they say. Having a lot of room is nice but will slow you down or you need more power to move

Doesn't seem to slow down the Piaggio! :stir:

Username Protected · **Posted:** 31 Dec 2025, 14:24

Username Protected wrote:

Excellent thread. You guys know so much. Articulate too!

Had a friend once tell me the Aerostar was so small you had to get out to change you mind. Always thought that was hilarious.

I am 6-5 and 225 lb and fit in the Aerostar just fine.

Many Barons and Bonanzas I don’t fit in without pain after 25 minutes. I barely fit in the Duke, but not comfortably. Twin Cessnas are good. Seneca OK. Aztec good. Cheyenne is tight with knees in the way, typical Piper. Can’t fly it well with my shoes on.

My head fits up into the skylite on the Aerostar, and I am right up to the glass up there. When I first flew them I thought it might be an issue in turbulence. The Aerostar does not feel turbulence like everything else due to the airfoil and wing loading. It has never been an issue.

The 58P club with highback seats was about the most claustrophobic experience I have had in a traveling machine. Couldn’t see behind much and couldn’t move much either.

Certainly I would not try to ride in the 5th or 6th seats in the 310 or Baron. The back bench or individual seats in the back of the Aerostar are not a problem because the cabin has the same cross section back there.

Username Protected · **Posted:** 31 Dec 2025, 14:28

Username Protected wrote:

Anyone know the hours required for an Aerostar annual inspection?

I have 42 hrs for a Baron
60 for a 421c
? For an Aerostar

The base labor figure will be in the same ballpark as the the 421.

Username Protected · **Posted:** 31 Dec 2025, 15:54

Just saw a guy do an annual on a 601P in 3 days, but they were 2 guys. So it feels like 80hrs+ is probably realistic number to budget for.

Username Protected · **Posted:** 31 Dec 2025, 22:25

Username Protected wrote:

The good news is that Lycoming cylinders are pretty bullet proof and seldom need changing.

Seems about right… we have a low time 1979 600A with 1560 hours on the original engines; looking through the logbooks I see the right engine had one cylinder removed/repaired back in ‘92… and that’s it! No other cylinder work. And it was the #1 cylinder at that. I hope I did just jinx us by mentioning it!