Alaskan Bush Tyres - approvals.

[HinterlandPilot]

Fellow Husky pilots - can you please help?

I have an A1 Husky on a G plate (in the UK) currently running Good Year 26’ tyres and I’d like to put on ABW 31’s but things are not too clear...

I have spoken to both Aviat and Airframes Alaska (AFA) and they have said there is an STC approval for theses tyres in place. However, AFA placed one caveat on the plane, it needs ‘heavy duty breaks’ which after research I cannot find any reference to.

I have four questions:

1). Can some one please point me to the 'heavy duty breaks' required for the Husky?

2). Is anyone fitting ‘heavy duty brakes’ to their Husky?

And now a couple questions (maybe for the European / UK Husky pilots?)

3). Despite Aviat and AFA saying these tyres can be fitted EASA’s STC of 2016 stipulates that A1, through to A1B requires a change of landing gear and tailwheel - to the ski specification version. Is this correct and has anyone on the forum had to do this?

FYI - Aviat have not referenced the change of landing gear as a requirement and when I spoke with them I was told, AFA hold the STC for the ABWs and they only reference using ‘heavy duty breaks’ as a requirement.

Unfortunately, my maintenance shop won’t fit the ABWs without the necessary changes of landing gear, approvals or a minor modification sign-off by the UK CAA all of which is complicated and costly!

4). My understanding is the UK CAA should allow these modification via the FAA bilateral agreement - is this correct?

If anyone can shed some light on the above or point me in the right direction for further advice I would appreciate this?

BTW - I have tried to speak with the UK CAA but I just get pushed around the organisation without it being resolved…

Many thanks,

Ed

 

[Snowbirdxx]

Here is the revelant part of the EASA TCDS for the A-1, it is NOT an STC. No heavy duty brakes BS.

11.The following main gear tires are approved for use on Model A-1: 6.00 x 6 4-ply Type III tube 8.00 x 6 4-ply Type III tube. 8.50 x 6 6-ply Type III tube. 24 x 10-6 Type III Tundra 26 x 10.5-6 Tundra and 8.50 x 6 tube. 12.Model A-1 are approved for use with the Alaskan Bushwheel P/N 31136, 31" Diameter Tundra tire. Model A-1 must have the Aero Ski gear P/N 35017-503 and 35017-504 installed in conjunction with the 31" tundra tires P/N 31136. The Scott 10" Model L3450 tail wheel must also be installed per Aviat Aircraft Drawing 35340 on the model A-1. FAA approved Flight Manual Supplement dated September 18, 1998 or later for the Tundra Tire configuration is required. 13.Models A-1 are approved for use with the Vision Microsystems Inc. VM100

Look on the FAA TCDS, same thing, just put them on and try to surround yourself with less DUFUS.

I an not sure which TCDS the CAA is using since they ar no longer in the EASA world, but the FAA TCDS says the same.

Type Certificate Data Sheets (TCDS) | EASA

The European Union Authority for aviation safety

www.easa.europa.eu

 

[GreggMotonaga]

Most of us here in the US would probably be using the Cleveland double puck brakes. I don't know what you have now, but anything less than an equivalent double puck system will likely not provide enough braking power with 31" ABWs.

 

[HinterlandPilot]

Here is the revelant part of the EASA TCDS for the A-1, it is NOT an STC. No heavy duty brakes BS.

11.The following main gear tires are approved for use on Model A-1: 6.00 x 6 4-ply Type III tube 8.00 x 6 4-ply Type III tube. 8.50 x 6 6-ply Type III tube. 24 x 10-6 Type III Tundra 26 x 10.5-6 Tundra and 8.50 x 6 tube. 12.Model A-1 are approved for use with the Alaskan Bushwheel P/N 31136, 31" Diameter Tundra tire. Model A-1 must have the Aero Ski gear P/N 35017-503 and 35017-504 installed in conjunction with the 31" tundra tires P/N 31136. The Scott 10" Model L3450 tail wheel must also be installed per Aviat Aircraft Drawing 35340 on the model A-1. FAA approved Flight Manual Supplement dated September 18, 1998 or later for the Tundra Tire configuration is required. 13.Models A-1 are approved for use with the Vision Microsystems Inc. VM100

Look on the FAA TCDS, same thing, just put them on and try to surround yourself with less DUFUS.

I an not sure which TCDS the CAA is using since they ar no longer in the EASA world, but the FAA TCDS says the same.

Type Certificate Data Sheets (TCDS) | EASA

The European Union Authority for aviation safety

www.easa.europa.eu

Tom,

Hi Tom,

Thanks for your reply - very much appreciated.

Can I please double check so I’m clear…

1). There’s no problem fitting the 31 ABW to the A1 and Airframes Alaska’s caveat about the heavy duty breaks are a misnomer / catch-all statement?

2). I’m slightly confused about the EASA TCDS statement (point 12 below), it says the, ‘A1 is approved to have the ABW 31s‘ then in a separate sentence its says, ‘must have Aeros ski gear installed in conjunction with the 31”. This to me infers that you have to have the Ski gear fitted if you want to install 31” ABW. Are these two separate points and not linked? Am I misreading this / missing the context of the statement?

3). For my educational knowledge how should I read a TCDS, is it purely for information and how does the EASA TCDS affect my A1 In relationship to the above?

12.Model A-1 are approved for use with the Alaskan Bushwheel P/N 31136, 31" Diameter Tundra tire. Model A-1 must have the Aero Ski gear P/N 35017-503 and 35017-504 installed in conjunction with the 31" tundra tires P/N 31136.

FYI the CAA are saying they are using the EASA TCDS’s.

Thanks in advance for explaining the above and helping out.

Best,

Ed

 

[HinterlandPilot]

Most of us here in the US would probably be using the Cleveland double puck brakes. I don't know what you have now, but anything less than an equivalent double puck system will likely not provide enough braking power with 31" ABWs.

Thanks for this information Gregg - much appreciated.

Knowledge about modifications etc you can do to the Husky is very limited here in the UK - the immediate default to any question or request is generally, NO! This is why the Fly Husky forum is so good.

I’ve got the standard brakes fitted by Aviat - FYI, the brakes hold the Good Year 26 very well when at full power.

Thanks again,

Ed

 

[Larson]

The standard factory fitted Aviat brakes, 30-60, are double puck and considered ‘heaven duty’.

If you had single puck brakes, these would not be considered ‘heavy duty’.

 

[HinterlandPilot]

The standard factory fitted Aviat brakes, 30-60, are double puck and considered ‘heaven duty’.

If you had single puck brakes, these would not be considered ‘heavy duty’.

Thanks for this Larson.

 

[Snowbirdxx]

1). There’s no problem fitting the 31 ABW to the A1 and Airframes Alaska’s caveat about the heavy duty breaks are a misnomer / catch-all statement?

Airfames AK simply has anSTC, afaik, it is not even accepted by EASA.

2). I’m slightly confused about the EASA TCDS statement (point 12 below), it says the, ‘A1 is approved to have the ABW 31s‘ then in a separate sentence its says, ‘must have Aeros ski gear installed in conjunction with the 31”. This to me infers that you have to have the Ski gear fitted if you want to install 31” ABW. Are these two separate points and not linked? Am I misreading this / missing the context of the statement?

That is not negotiable. In the late 80 several A-1 has gear failiures with big tires and or Wheel replacement skis. What happened? On bad landings the bungees stretched, gear deflected and the bungees pulled it back in. Then there was the sudden stop on the gearblocks. The stop sheard the axles off or bent the gear and the diagonal strut. Then AV-Alaska STCd a really ugly jury strut that connected the main tube with the diagonal strut to reduce the critical knicking lenght. Problem was not solved but symtoms were less. SGS then solved the problem and no more gear failiured happened. Stu at Aviat never understood what the SGS does.


3). For my educational knowledge how should I read a TCDS, is it purely for information and how does the EASA TCDS affect my A1 In relationship to the above?

The TCDS is the hard law. not negotiable, unless STCd.

12.Model A-1 are approved for use with the Alaskan Bushwheel P/N 31136, 31" Diameter Tundra tire. Model A-1 must have the Aero Ski gear P/N 35017-503 and 35017-504 installed in conjunction with the 31" tundra tires P/N 31136.

FYI the CAA are saying they are using the EASA TCDS’s.

Give me a call at 0049 0nefifeseven 868 sevenvivezerro aigt 2

Greetings TomD