fudog50 wrote:
Not bad Mary, here is a little more about aircraft windshields and the
requirements for replacing them, and the maintenance effort. Ok, they
are laminated, and each manufacturer puts out specs on how much damage
(layers) and where the damage can occur. If the damage is in the
windshield heat section, or is in a certain structurally unsafe
section, or obscures the pilots scan (safety of flight issues) it's
outta there. It is a relatively easy replacement, the only real issues
are the hundreds of screws, the lengths, making sure you get the right
ones back in the right spot, and the sealant. If it is cold weather
obviously it's gonna take longer for it to seal. It takes additional
time to find hangar space, move assetts, do a respot if it is cold out
and you need 55 deg for a good cure, otherwise you can do it out on
the line. Then you gotta do a pressure check to check for leaks which
requires pressurization of the whole aircraft (neg) on the deck. It's
a requirement for the Navy, not sure about the civvies. I've heard
knuckleheads say, "why do a pressure check? we''ll know if it leaks
when we get to altitude." Usually we take an aircraft off the schedule
for at least 12 hours, (6-12 hours given for cure time, about 2-4
hours for maintenance and the pressure check). Anything less is a
calculable risk made with all professional entities, (ops and
maintenance) dictated by a flight schedule driven by a profit, or
mission accomplishment. Next time you see an aircraft delayed for only
8 hours for a windshield replacement, the only thing that could make
it that fast would be a sealant that has about a less than 2-4 hour
cure time. Wish we could get our hands on some with a milspec.


Our shop has done replacements where we told flight ops that the
plane needed to sit for 24 hours for the sealer to cure, but they
flew the plane in less than 12 hours. We haven't had any reports
of pressure leaks, but they did do a lot of complaining about how
the sealer was streaked down the sides of the fuselage, after the
flight.



--
Paul Stevens

Bill 'n' Opus in 2004