Closest I could find right now, outdated though, 2007 http://www.navybmr.com/study%20material/NAVAIR%2004-10-506.pdf.
http://defenseph.net/bootcamp/wp-content/uploads/2018/11/6.jpg
^That shows how you measure extent of cracking, cuts, chunking or other damage which frankly
can be classified as more-localized effects than the cumulative wear apparent in the Morota pics.
Setting aside the obvious differences in tread-wear rates between USAF and USN contexts (since
the launch and recovery/landing methods are different), Section 3-8 ("TREAD WEAR"), as already
cited by jet, seems more appropriate, with respect to what sbhntr -who should be lauded for it-
spotted in the Morota photographs.
Fig 3-2 illustrates tread sections exhibiting different types of wear, for use as a diagnostic tool in
detecting camber/inflation problems, but also includes an illustration of "EXCESSIVE" wear, with
the tread ribs completely gone:
http://oi68.tinypic.com/90oxzr.jpgSection 3-8a mentions tread-wear indicators, which are oblong pits in the ribs: basically, once
the rib wears down to flush with the tread-wear indicator, it's past time to replace tires. In the
Morota photos that started this thread, there is zero rib remaining visible, so to me, it's rather
superfluous to ask where the tread-wear indicators would have been. The ribs are gone, the
protector ply seems gone in spots, potentially on down to past the undertread.
In any case, I understand that unlike USN, USAF refers to MWL markings (max. wear limit) on the
tire sidewalls (per MIL-PRF-5041 Rev. J), but marginally-overinflating the tire could cause the tread's
center to wear down excessively, long before the MWL marks would be pinged: such a trick might
artificially "prolong a tire's service life", but at what risk/cost? USN's safeguards seem much more
reliable.To get back to USN NAVAIR...
Although 3-8a notes that "the exposure of nylon plies (fabric reinforcement, casing, etc.) is
not considered a wear depth indicator", it also states "the maximum allowable tread wear for
tires not having wear depth indicators shall be when the tread pattern is worn to the bottom of
the tread groove at any spot on the tire, regardless of whether wear is the result of skidding or
normal use.", and this is what I believe we are seeing in the Morota photos.
Fig. 3-3, although illustrating much more localized skid (excessive brake) effects, nevertheless
also shows how the compromise of multiple tire layers/plies can lead to catastrophic failure. In
the photos that led to this discussion, we see nowhere near Fig 3-3's level of localized damage,
and for the likely reason that the braking environment and process in USN recovery is different
from that of USAF or PAF landings. Fig. 3-3 most likely shows tire damage after a single event
of skidding/excessive braking, whereas the wear visible from the Morota photos is more likely
the cumulative result of several landing cycles.
Ultimately...
If PAF TO allows such a state of aircraft tires, there may be nothing left to discuss, especially
given how some want to interpret this thread as a personal attack on members of PAF, and/or
as a wholesale attack on PAF itself.
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