The report said that when the new port
tires were installed ten days earlier, they had
been inflated to 115psi, though the spec was
145, +-5psi. Regardless, a newly-installed tire is
particularly prone to losing pressure, not only
through routine leakage but as it takes its initial
set. The NTSB continued, “Goodyear Chief
Engineer, Aircraft Tire Engineering, stated:
The pieces from all tires showed substantial
heat in the shoulder/upper sidewall area. As
the temperature elevates, the strength of the
These burst tires show how severe a failure can be – inconvenient in road transport but potentially
fatal in aviation.
nylon cord will decrease. The temperature
levels that were obtained...were sufficient to Military tires serve different compared to the rest of the vehicle.
cause the nylon cord to fail.” His conclusion: missions We get one landing on the mains; the
“Taking into consideration that these tires were Mays explained that the military nose tires are typically used twice.”
under inflated initially, were installed on the needs tires of higher performance
aircraft immediately with no allowance for tire than are required for civilian or even Considerations for pilots and
growth and had no inflation checks in the last commercial use. Fighters’ tires, mechanics
3 days, the tires could potentially have been especially, are small for their own Remember that heat is the enemy
under inflated by up to approximately 50% at weight and for the weight and speed of tires, and heat exposure has a
the time of this takeoff.” CIGNA (the insurance of the aircraft. Speeds for all phases of cumulative effect. Civilian industry
company) received the remains of the Learjet. the mission – taxi, takeoff, and landing recommendations include replacement
http://ntsb.gov/ntsb/brief2.asp?ev_id=20001206X01820&ntsbn – are high. of a tire if it has run one cycle (takeoff
o=NYC94FA123&akey=1 The tradeoff: a fighter’s tire life is or landing) at pressure under 90% of
typically half what one would expect its recommendation.
Delta L-1011 N40DA – August 7, 1997 in a civilian application (if there were Taxiing builds heat fast. Hot surface
This heavy taxied some 11.3 miles in a a parallel set of conditions). Mays operation can reduce tire life. Mays
3-hour period prior to takeoff. The NTSB explained, “You’ll see that military says “You can see 30-40% difference
report says, “There was no temperature tires are smaller, lighter, harder. in wear, summer to winter.”
gauge or tabular data available that could Rubber generates a lot of heat when Abrasive surfaces wear tires faster.
have informed the crew that heat buildup flexed, and it is a good insulator. We Wet or grass runways are easier on
resulting from taxi distance was now at have to develop compounds that tread wear. (These surfaces are also
a level that potentially threatened the generate less heat. Such compounds generally cooler than similarly-located
integrity of the tires. During the takeoff roll, generally get fewer landings, other pavement; but they carry drawbacks
the 3F tire exploded, resulting in vibration, things’ being equal. Deflection is not of their own.)
shudder, and yaw… The abort was initiated drastically different; it’s mostly the Use nitrogen, not air, to fill high-
about Vr (165 knots)… A brake fire began differences in materials. Nor does performance tires. Air can lose or gain
while the aircraft was stopping… An weight change much for a given a percent of pressure with each 5°F
inspection of the 3R tire showed bead quantity of rubber.” Military tires temperature change. Air’s humidity is
separation had occurred. The estimated typically have a heavier nylon cord not regulated.
bead temperatures during the takeoff roll than civilian issue, to better-contain Avoid scrubbing tires:
reached between 350 and 400 degrees their pressure. He explained, “Military - avoid differential braking (especially
Fahrenheit. The bead begins to degrade tires typically have a larger nylon cord the inside tire)
between 250 and 280 degrees Fahrenheit.” than civilian issue, to better-contain - avoid making tight turns
http://ntsb.gov/ntsb/brief.asp?ev_id=20001208X08661&key=1 their often-400psi of nitrogen and - go one more taxiway before turning
get a higher strength/weight ratio. off the landing runway, and slow down
Air France Concorde F-BTSC - July 25, 2000 However, a given tire will go through Taxi slowly and minimally
The most notorious tire-related airplane only so many [heat] cycles. Tires with …and check pressure before
disaster was a FOD incident. The Concorde higher strength/weight will not last as every flight, or at least daily. Proper
ran over a piece of metal that had fallen many cycles [as lighter-duty tires].” inflation is the biggest guarantee of
from another airplane and the tire failed; The big difference is in a military good performance.
AM
pieces of that tire punctured the fuel tank tire’s after-life. “Unlike commercial
and severed the hydraulic control lines. 109 tires, military tires rarely get retreaded, Severe braking can scrub
people died aboard the Concorde; four [so] a long-lasting carcass serves no
the surface.
more were killed on the ground. The tiny purpose.“ As performance rises, life
Concorde fleet underwent extensive rework, expectancy drops. “Space Shuttle
before it briefly resumed its revenue service. tires are the ultimate in performance.
http://www.concordesst.com/accident/cause.html The Shuttle tires are not very big
20 Aviation Maintenance | avmain-mag.com | February/March 2010
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72