406 ELT conversion

[Jeremiah Rigueiro]

Wondering if anyone has had a new shelf made in their plane to accommodate one of the new 406 elt's and the G-force requirement the STC imposes on them.

This is on a early model (sn 30-603) twin.

Thanks!

[N3322G]

Hi Jeremiah and welcome - I see this is your 1st post here.

I had the ACK-406 put aft of the baggage in the fuselage where there was an existing shelf for teh ELT in my 1970 PA39 two years ago and ran the wires under the floor forward for the 'tiny' ELT panel. Have yet to hook it to the GPS but all else works fine in test mode. This made it an easy mount for the ELT antenna and kept it away from all other antennas - so very similar to the old ELT locations except for the stuff up front.

Hope this helps.

[Jeremiah Rigueiro]

Thanks for the prompt response.

Found and avionics shelf back there that is vacant that will work perfectly.

We just got this Comanche last month and are getting it ready to be used in remote village operations in Alaska. Any advice for winter operations or mods would be appreciated.

[Kristin Winter]

Insulate ducts from the heater into the cabin. Tune up the heater for maximum output and do a decay check if it is do. Get a CO detector. Check to make sure that the fresh air duct from the dorsel fin to the overhead vents is intact. If you can't be sure, plug it at the dorsel fin in cold weather. Check the ducting to the defrost vents. Get lightweight starters that have a solenoid instead of a Bendix that can fresh up, preventing starting. Install copper cables from battery to starter.

That is all the cold weather stuff I can think of off the top of my head.

[N3322G]

I'm assuming you've done cold weather ops before and know to be extremely diligent on fuel sumps. Fuel sumps have come up so often I wrote down what we do and it was well received. In case you didn't see it get published in the Flyer -

N3322G FUEL HYGIENE

This is the process we use to sump fuel on our Twin Comanche. It has evolved from the methods we were taught. The results are that the fuel sump screens are remarkably clean at each 50 hour AD inspection – so much so that shops have commented upon their cleanliness. Sumped fuel has been entirely water and debris free for almost two years or more of flying. I should mention that all bladders were replaced in 2009/2010, fuel door seals are fresh and I do my best to keep the fuel caps in good condition. When home, the aircraft is hangared in Texas where the heat eats rubber for lunch.

1. Before the first flight, place 30 gallon sterlite bin bottom under sump drain lines (or something that will catch fuel)
2. Start with selectors on main tanks
3. Sump right main by holding up rear sump drain
4. While holding sump open, change to right aux (notice movement of mechanism in sump area)
5. While holding sump open, change right selector to crossfeed
6. Release sump drain
7. Return selector to right main
8. Sump left main by holding up forward sump drain
9. While holding sump open, change to left aux (notice movement of mechanism in sump area)
10. While holding sump open, change left selector to crossfeed
11. Release sump drain
12. Return selector to left main
a. If fuel in tips - with selector on right aux, turn on master and switch to right tip
b. Sump right tip by holding up rear sump drain
c. Return switch to aux
d. Return selector to right main
e. If fuel in tips - with selector on left aux, turn on master and switch to left tip
f. Sump left tip by holding up forward sump drain
g. Return switch to aux, master off
h. Return selector to left main
13. Check fuel in bin. If debris, individually sump tanks until sumped fuel is clean
a. If fuel in tips, sump right tip external sump on tip
b. If fuel in tips, sump left tip external sump on tip
c. If nacelle tanks have fuel sump at external sump valves both sides
d. If Miller wet wings have fuel, sump at external sump valve on both sides
14. Fly
15. Fuel main and aux tanks (and any other desired tanks)
16. After last flight of day, sump main and aux tanks again - per service bulletin

Don't know how much TwinCo time you have - helps this helps if the Twin is new to you.

[N3322G]

Another thought since this Twin is new to you - If I were going back to AK, I'd want to be extra sure the entire landing gear system is extremely happy. If conduits and wiring harness haven't been done, I'd suggest the teflon conduits and comanchegear.com harness and have a Comanche Pro mechanic check the transmission and motor.

[Jeremiah Rigueiro]

Yes, we are familiar with the extensive fuel sump AD for freezing temps.

Mechanically the airplane has been looked through well and is in good shape. Bungees done this year.

We have operated Aircraft in Alaska for many years now, but never a Comanche. I simply have heard rumors about the wings not doing very good with ice. We are considering options for ice abatement, but are running out of time to perform extensive work on the plane before winter hits.

Would simple upgrades such as VG's help?

What is your educated experience as pilots when encountering icing with the pa-30 wing?

We want to have a safe plane in which we are capable of flying IFR, but right now some of our pilots are giving the plane the stink eye

In regards to twin Comanche time, I am the only one in our organization with time in the cockpit. But it was in TN and it was years ago. Never had to deal with icing.

Thanks for your responses.

[Kristin Winter]

Jeremiah,

I am glad that you have had the landing gear looked at by maintenance personnel who are thoroughly familiar with the Comanche landing gear system. It is a good system, but it doesn't have mechanic down locks so proper rigging is key. During pre-flight, if you can push up on the drag links where they break and observe any movement, then you have a problem.

I have put ice on a Twinkie. We had a member here for years who flew a Twin Comanche throughout the Great Lakes for decades. He was in his 80's when he died. He always claimed that a Twinkie would carry six inches of ice. I have no such personal experience, so cannot endorse that claim. I have had 1/2" of ice and it was a non-issue. The plane will definitely handle more than that, but can't say how much.

The Twin is a great plane, though it wouldn't have been my first thought for the Alaskan bush. As much as anything I wonder about what gravel will do to the slow slung aircraft, particularly props and stabilator. Other than the additional fuel burn of an Aztec, it would seem more suitable.

[N3322G]

As much as I like the Twin, as Kristin said, with 11 inches of prop clearance, it would not be my 1st choice for AK rural flights on gravel runways - ours has been there but only when it was due for a prop O/H anyway. If you are operating primarily on hard surface - different mission parameters. Can't speak to heavy ice on the Twin other than to say, 1/4 inch dropped the speed 10 kts during a race I was competing in. The prior owner, Mom, flew in the upper midwest for years and would attest to the tune that is played on either side of the nose when what ever ice is there does come off - benefits of a 30 vs a 39 is only one side needs repair.

[Kristin Winter]

Pat,

Sorry to say, the PA-30 gets both sides of the nose too. It is just that the right side is down low, instead of up high.

[N3322G]

Thanks Kristin - always something new to learn. After 10 weeks and $20,000 - we run away as fast as our little 160s can carry us from any ice.