Tail Rotor Pedal Squeak and Missing Safety Wire on an H125
An H125 comes in with a reported squeak from the tail rotor pedals. A previous shift lubricated the pedal pivot and released the aircraft after a ground run, with a log entry saying 'squeak not reproduced'. The next crew reports a slight yaw kick in cruise and a pedal that feels 'notchy'. You remove the centre console panel and find a tail rotor control turnbuckle with no safety wire, cable tension 15 percent below the rigging limit, and wear on a fairlead. The aircraft has 2,340 hours. The previous shift was working under a tight turnaround and did not remove the console panel. The operator wants a quick cable tension adjustment and release.
1. Evaluate the airworthiness of the aircraft with the missing safety wire and low cable tension. Can it be released after a quick adjustment?
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The aircraft is not airworthy as found. A tail rotor control turnbuckle without safety wire is a locking failure in a critical flight control. Low cable tension can allow cable slap, lost pedal travel or asymmetric tail rotor response, and the notchy pedal and yaw kick are consistent with a control rigging fault. The fairlead wear may also cause binding or chafing.
A quick tension adjustment is not enough. The turnbuckle must be correctly rigged, safety-wired, and the entire tail rotor control system inspected for damage, wear, cable condition and correct routing. The yaw kick must be explained, not just tuned out. Until the rigging is within limits, the safety wire is fitted and a functional check is satisfactory, the aircraft should remain grounded. The previous release was premature because the console panel was not removed and the squeak was not reproduced.
2. What rigging and inspection steps should be completed before return to service?
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I would consult the maintenance manual for tail rotor control rigging. I would inspect the cables for broken strands, corrosion and correct diameter; check pulleys and fairleads for wear and alignment; check the turnbuckle threads for engagement and condition; and verify the pedal assembly and bellcrank for wear. I would set cable tension to the specified value at the specified temperature and recheck after cycling the pedals.
I would fit new safety wire or the specified locking device, using the correct wire diameter and twist. I would check full pedal travel, tail rotor blade pitch range and rigging pin positions. Then I would perform a ground functional check and, if permitted, a maintenance test flight to confirm no yaw kick, no binding and correct response. The fairlead wear should be rectified or assessed against limits. All results should be recorded, including the final tension and the safety-wire inspection.
3. What human factors contributed to the earlier release, and what would you change?
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The earlier release shows a short-cut caused by time pressure and a 'not reproduced' mindset. The previous shift did not remove the console panel, so the inspection was incomplete. A ground run may not reproduce a control fault that appears in cruise. The log entry made the absence of a finding sound like a satisfactory check, which can mislead the next shift. Turnaround pressure also encouraged a lubrication-only fix.
To prevent recurrence, I would require a proper duplicate inspection or independent check for flight-control rigging after any adjustment. I would improve shift handover so unresolved symptoms are carried forward as open defects, not closed with 'not reproduced'. I would make sure the maintenance manual inspection access is followed, even under turnaround pressure. I would also encourage anyone to stop the release when a control symptom is unresolved, and record the reason for any panel that was not removed.