Bulkhead replacement in NR 65.5 blade
Replacement of a damaged bulkhead (commonly called the „floor”) inside an NR 65.5 blade - 130 working hours, two teams, and a turbine returned to service 34% faster than planned.
The primary objective of this operation was to replace a damaged bulkhead-commonly referred to as the “floor”-inside the blade. Damages of this type, often resulting from operational stresses or manufacturing defects, require swift and efficient intervention.
Unfortunately, this type of repair necessitates shutting down the turbine for the entire duration of the work. For this project, two teams clocked a total of 130 man-hours, completing the entire scope within 7 days. The success was driven by meticulous logistical planning and the technicians' experience-both in rope access techniques and expertise gained from previous complex repairs.
Preparation and Work Standards
Every stage required strict discipline in workspace preparation. Working inside a blade constitutes a confined space entry-installing high-capacity ventilation and monitoring the atmosphere (oxygen and gas detection) are foundational processes for safe and effective work. Thanks to efficient equipment transport management, we were able to maximize the time spent inside the blade.
Work Schedule
- Day 1: Started on standby due to high winds. We utilized this time for vertical logistics planning and detailed resource mapping.
- Day 2-3: Intensive cutting out of the old floor and transporting equipment to the nacelle. We also handled the removal of fiber optics and pre-prepared new components on the ground (abrading the surfaces of new joints).
- Day 4: Finalized the removal of the old structure.
- Day 5: The critical moment-final grinding of the interior to prepare for bonding. We secured the hub and blade and prepared the chemical resins.
- Day 6: Despite an unsuccessful first transport attempt and weather disruptions, we successfully bonded the first element.
- Day 7 (Final): The longest shift (15.5h). Using a zip-line and an electric power ascender, we brought 4 floor sections into the hub. After precision trimming inside the blade, we bonded all elements and initiated the laminate post-curing process.
Technical Summary
The final phase involved sanding the horizontal joints from the inside followed by final lamination. The entire process-from cutting cables and grinding to multi-stage heating-was carried out strictly according to the manufacturer's instructions.
What allowed us to reduce the operation time was the seamless cooperation between the two teams. Utilizing electric power ascenders and a zip-line to transport bulky items through the hub allowed the team to save their energy for the most high-precision tasks: the internal trimming of the “blade” and structural lamination. The result: 130 hours of solid technical work, with the turbine returned to service 34% faster than the original schedule projected.
Seven days on a turbine is a battle against logistics and weather. The key was synchronization: while one team was grinding the interior of the blade, the second team on the ground was already preparing the new components and chemicals. This meant that as soon as the weather window allowed, we were bonding the next sections without a single minute of unnecessary downtime.
