SA 365 N: bearing flight hours before installation

Before installing a used bearing on an SA 365 N helicopter from 27 October 2026, establish its flight hours since first installation, including use on previous aircraft. According to our reading of the AD, a part already installed on that date must be replaced within 500 flight hours after 27 October, regardless of its history. Distinguishing the two prevents the wrong deadline calculation.

Two different rules

An airworthiness directive, or AD, imposes safety measures. EASA AD 2026-0195, effective from 27 October 2026, covers all Airbus SA 365 N helicopters and tail gear box control rod bearing P/N 360A33-4052-00. Premature bearing spalling could lead to loss of yaw control, meaning control of the direction in which the helicopter's nose points. A part number identifies the design, not an individual item's identity.

Paragraph 1 of the AD uses the later of two limits: within 500 flight hours after the effective date, or before the part accumulates 500 flight hours since first installation. For a part already installed on 27 October, the second limit cannot be later than the first. Our reading therefore gives an initial replacement deadline within 500 flight hours after that date, regardless of previous accumulated use. Confirm this reading for your aircraft with the maintenance organisation or Airbus.

Paragraph 2 concerns installation from that date, including a stock or exchange part. An affected part must then have fewer than 500 flight hours since first installation and be replaced before reaching that total, subject to the AD's eligibility conditions and Airbus instructions. For this installation, the part's history determines the remaining time: changing helicopters does not reset its counter.

Reconstruct continuity, not just a total

We suggest a sheet for each part, with one row per period of use: aircraft, installation date and counter, removal date and counter, flight hours assigned to the part and supporting record reference. Add the available identification that connects the physical item across records, beyond its commercial part number.

Review release documents alongside installation and removal records and utilisation reports. One document may explain an intervention without establishing all earlier use. A missing period cannot be counted as zero.

Fictional example: 180 flight hours followed by 120

A part accumulated 180 flight hours on one aircraft and 120 on another. Its documented total is 300 flight hours. If this affected part is proposed for a new installation after the effective date, tracking must start at 300 flight hours and schedule replacement before 500, subject to other eligibility conditions. It does not restart at zero.

If the first 180 flight hours appear only in an email, keep that statement as a lead and request its supporting record. Mark the total as unconfirmed instead of turning an estimate into an established fact. Competent personnel must resolve that uncertainty before relying on the calculation for an installation decision.

Make the calculation transferable

Keep individual periods, their sum and the applicable rule in separate fields. The next person can then check both the arithmetic and the chosen AD paragraph. Record the version consulted and verification date: an accurate sum does not prove that the regulatory deadline was selected correctly.