AD 98-06-33
Unsafe Condition
Sudden movement of the actuator of the main landing gear (MLG) under extreme inward sideload conditions (such as touching down at a large crab angle) may pressurize the downlock-actuator and lift the MLG toggle-links, which could result in collapse of the MLG and reduced controllability of the airplane during landing.
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Required Actions
Replace flexible hydraulic hoses, part number A71462-401, connecting to the UP-port of the MLG actuator with new hoses, part number 97867-1, which have built-in restrictor check-valves, following Fokker Service Bulletin F28/32-123, Revision 1.
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Compliance Time
Within 12 months after the effective date of this AD (April 27, 1998)
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Affected Aircraft
Fokker Model F28 Mark 1000 through 4000 series airplanes equipped with flexible hydraulic hoses, part number A71462-401.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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