The International Cessna^® 170 Association

Wondering about bolts to fasten aft vert stab to empenage. In the IPC figure 13 shows attachment of "Fitting rear spar lower " with bolt NAS145-14s and NAS145-18. These are like big allen key bolts with hex socket in heads. Are these special and/or could regular AN bolts also be used? Thanks G

I replaced those bolts on my plane while rebuilding it. If memory serves me correctly you couldn't get an external wrench on a standard bolt at that location. The fit is too tight. Those bolts aren't hard to order and are the only bolts I know of to fit there, as well as being the only "correct" bolts to use. Also I think they have special washers you have to use with them, that are chamfered in the opening, because the bolt is radiused at the shoulder. Good luck, Jon

The NAS145-14 & -18 bolts are special high shear and have been replaced by MS 20005-6 & -11 bolts and high shear chamfered washers P/N MS 20002-5. I ordered my replacement bolts/washers from Genuine Aircraft Hardware. Check them out on the web: http://www.gen-aircraft-hardware.com Also belive the minimum order for the washers was 25; so, make sure they are the high shear / chamfered ones. If I remember correcly, I ordered the wrong ones the first time.

I concur with jlwild. The MS20005 bolts are equivalent replacements.
I also concur with where to get them! (Genuine Aircraft Hardware).

Here are my notes when I ordered from them:

(2) MS20005-6 bolts @ $7.88 each = $15.76
(5) MS20005-9 bolts @ $8.58 each = $42.88 (sold in packages of 5 only)
(25) MS20002C5 counter-relieved washers @ $0.26 each = $6.50 (sold in packages of 25)
(25) MS20002-5 hardened washers @ $0.13 each = $3.18 (sold in packages of 25)

Total = $68.32 (+ shipping)

For what it's worth, buying the "original" NAS145 bolts from Cessna
would have cost $116.45 each (ouch....).

Guys thanks That answers all my questions Cheers Gary

Additionally,...using ordinary AN hardware in that location places unusual stress on the fitting because the chamfer/profile does not match. I've seen a few aircraft with ordinary AN bolts there. I wouldn't fly in them. IMHO. (And I wouldn't want to have to try finding replacement angles/attachment fittings when they eventually develop cracks.)

I am just reviewing notes from Bel and Jim . You note the dash numbers are different . two bolts with dash 6 but Jim I think you list dash 9and Bella, dash 11. Also You list 5 (five of the longer ones) I see spots for only 2 so where do the other 3 go?? Gonna order these up if you might be able to clarify these points. Thanks G

If I remember right, when I called them for the order,
they didn't have the exact dash-numbers on-hand (hence
the longer ones I reference).

The additional number of bolts stems from the fact that
(at least when I called them), you could only purchase
said bolts in lots/bags of five.

Maybe give them a call, and see if they have exactly what
you're looking for in the quantities you're after.

just had the conversation with the General Aviation Hardware folks. Same as you guys so have lots of extra washers if anyone needs. Thanks again for your help Gary