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Airworthiness Directive 98-26-06

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Official AD 98-26-06 · FR doc 99-1064 · 1999-01-19 · airframe

Airworthiness Directives; Schweizer Aircraft Corporation Model 269D Helicopters

What this AD requires

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-26-06 which was sent previously to all known U.S. owners and operators of Schweizer Aircraft Corporation (Schweizer) Model 269D helicopters by individual letters. This AD requires removing the main rotor drive shaft (shaft) and inspecting it for cracks. If a crack is found, replacing the shaft with an airworthy shaft is required. This AD also requires periodically verifying the torque of the main rotor hub (hub) bolts. This amendment is prompted by four reports of cracking in the shaft of helicopters with a large diameter hub. Wear patterns indicate cracking was caused by loss of clamping torque on the hub and shaft assembly due to the use of grease between the hub and shaft. This condition, if not corrected, could result in failure of the shaft and subsequent loss of control of the helicopter.

Which aircraft AD 98-26-06 applies to

Applicability depends on the aircraft’s type certificate — check it against the specific tail.

Whether AD 98-26-06 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.

How AD compliance is recorded

A valid compliance record (14 CFR 43.9) states:

Method of compliance — The specific action taken (inspected, replaced, modified) and to what revision.
Date — When the work was done.
Aircraft time — Total time in service / tach at compliance — how recurring next-due is computed.
Signature & certificate — The A&P/IA who returned it to service, with certificate number.
Is AD 98-26-06 complied with on your aircraft?

Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.

Look up a tail number →Read the full directive (Federal Register)

Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.