Main gear toe in

[lowNslow]

In fact, the second SNL you posted implies that “all service information” previously published was “approved” which might include the Owner’s Manual service information. Certainly the information is the SAME info... therefore it could be said to be “approved”.

Hmm...gotta go with Gary on this one, it specifically states what other sources are also approved and no mention of the Owner's Manual. In either case we now know how to adjust the toe in.

[ghostflyer]

The owners manual is a good read and shows the basics. I have seen where some where ??? Where it’s written that the aircraft have to be at max weight On slip plates before measuring toe in and camber. It’s also written about the shimming and alignment of the undercarriage leg first .Plus the aircraft had to be in the flying position.[tail up] I used to do alignment this way To Cessna 180,s in the military and when mine came along did it that way . I haven’t had any issues in the last 20 years of flying the 170a . Haven’t been that involved in many of the 180,s and 185,s that have come through the shop recently . I would be interested to hear what’s in the bird dog manual. Is there a direct reference in any manual stating on how to do a correct wheel alignment .

[n2582d]

... I would be interested to hear what’s in the bird dog manual. Is there a direct reference in any manual stating on how to do a correct wheel alignment .

L-19 Wheel Align 1.jpg

L-19 Wheel Align 2.jpg

L-19 Wheel Align 3.jpg

[GAHorn]

I’d like to repeat an idea which another Member offered years ago, as an alternative to greased plates.... one might consider using two Heavy Duty plastic garbage bags. They are durable and very slippery when laid one-upon-the-other and the top bag will allow the gear/wheel to slip/slide and will “wad” up and readily indicate the out-of-alignment condition which is decipherable without having to make or deal with plates and grease.

Place the pair of bags in front of the wheels and roll the airplane forward onto the bags and observe the reaction as the bags “slip” and allow the strain to relax on the mis-aligned gear.

[dstates]

I’d like to repeat an idea which another Member offered years ago, as an alternative to greased plates.... one might consider using two Heavy Duty plastic garbage bags. They are durable and very slippery when laid one-upon-the-other and the top bag will allow the gear/wheel to slip/slide and will “wad” up and readily indicate the out-of-alignment condition which is decipherable without having to make or deal with plates and grease.

Place the pair of bags in front of the wheels and roll the airplane forward onto the bags and observe the reaction as the bags “slip” and allow the strain to relax on the mis-aligned gear.

I’ve never done it but I think I read somewhere here on the forum to use the bags and spray the inside with some sort of oil. Does that work well?

[GAHorn]

I’d like to repeat an idea which another Member offered years ago, as an alternative to greased plates.... one might consider using two Heavy Duty plastic garbage bags. They are durable and very slippery when laid one-upon-the-other and the top bag will allow the gear/wheel to slip/slide and will “wad” up and readily indicate the out-of-alignment condition which is decipherable without having to make or deal with plates and grease.

Place the pair of bags in front of the wheels and roll the airplane forward onto the bags and observe the reaction as the bags “slip” and allow the strain to relax on the mis-aligned gear.

I’ve never done it but I think I read somewhere here on the forum to use the bags and spray the inside with some sort of oil. Does that work well?

I didn’t find it necessary. YMMV

[Bruce Fenstermacher]

Slightly off topic. Does anyone (Gary) have Cessna dwg. No. 0541150. This is the drawing that Goodyear cross wind gear must be installed. I'm hoping there is no difference between the toe-in or out specification for cross wind gear compared to straight axles. There might have also been a Goodyear instruction sheet. I'd think it would be critical the cross wind gear be 0 toe in and 0 toe out, other wise they'd be fighting each other all the time.

[n2582d]

I don't have that drawing but the Goodyear Crosswind Gear Installation Instructions you posted in the Mx Library shows the toe-in specs.

Screen Shot 2020-05-19 at 5.55.48 PM.png

I assume, but don't know for certain that that is 1/16" toe-in (+/- 1/16") for each wheel. I enjoyed your tale of the crosswind gear almost taking out the taxiway lights at that convention fly-out. That must be why Goodyear includes these instructions:

Screen Shot 2020-05-19 at 5.56.49 PM.png

[n2582d]

Gary, that was done retroactively I believe. Note those particular ones were issued in 1958. I have (and gave away entire copies of the early ones at Kelowna convention) the early SNLs that were not approved by anyone but Cessna publications dept. In fact, the second SNL you posted implies that “all service information” previously published was “approved” which might include the Owner’s Manual service information. Certainly the information is the SAME info... therefore it could be said to be “approved”.

My old post regarding the Owner’s Manual not being an approved document is still valid under either assumption.

Edit: Another example is the performance data in the Owner’s Manual. Although it is incorporated into that unapproved manual... the data itself is IDENTICAL to that “CAA Approved” in the AFM. While the entire OM is not approved, it contains approved data.

George, I appreciate the edit. In various threads here you've reiterated that the Owner's Manual is not an approved document and that it was put out by the marketing or sales department at Cessna. To me that insinuates that the information contained in the Owner’s Manual such as weight and balance or performance data is inaccurate; that it's hyperbole. As you've clarified in this edit that is simply not the case. Granted there are some errors like the illustration showing elevator travel in the '52-'55 models to be 28º up and 17º down -- a carryover from the 170A illustration. (This was finally corrected in the '56 Owner's Manual). As you've pointed out elsewhere, TCDS A-799, the gold standard of FAA-approved data, also has had it's share of errors.

Regarding old Service News Letters being approved material I wrote Tech Support at Cessna the following, "After the C-170B was discontinued Cessna issued an SNL dated 3-31-58. ... Does it apply retroactively to all Cessna service information issued prior to 3-31-58? My interpretation would be that it indeed does apply to earlier bulletins and letters as far back to at least 1946.” Geoff Kelly responded,

SNL58-3-31 is considered inactive, however your interpretation is correct. Issued in 1962, the 1953-1962 100 Series Cessna Service Manual D138 is still currently regarded as the correct supplemental manual for the older aircraft per the statement below. Any topic not covered in earlier service documents or the owner’s manual may be referenced in this 100 Series Service Manual. Naturally, if any specific procedure is covered both in an old inactive service bulletin and the service manual, the current service manual should take precedence. A great resource can be found at https://support.Cessna.com, which holds all current service documents free of charge (except service/maintenance manuals) and also lists inactive publications.

In a screenshot from the forward to the 100 Series Service Manual he highlighted the sentence, "Although not specifically written for earlier models which have been discontinued, much of the information can be used as a guide for maintenance of the Model 120, 140, and 170."

So -- to get this thread back on track -- the information for wheel alignment from SLN 56 is FAA-approved data according to Tech Support at Cessna.