Airbus A380 har begåvats med sin första AD-not (Airworthiness Directive).

Den gäller de flygplan som har Rolls Royce motorn Trent 900 installerad. Det är ledskenorna i motorn som kan uppvisa sprickor. De motorer som påverkas kommer uppvisa sprickor inom 1000 flygcykler.

Fullständig information finns på

http://ad.easa.europa.eu/ad/2008-0202

Men noten säger bland annat:

"Evidence from development testing and flight test Trent 900 engines has
identified cracking on some HP Turbine Nozzle Guide Vane (NGV) Convex
Surfaces. Analysis of test data and review of the manufacturing process has
revealed compounding effects that may contribute to a shortfall in component life
and an increased likelihood of premature cracking in this region. Excessive
cracking on the Convex Surface may lead to the release of NGV material or the
blockage of Turbine gas flow. This results in a risk of fracture to the HP Turbine
Blade.
Not all NGV assemblies are affected. It is believed that the problem, if it exists,
will manifest itself below 1 000 cycles.
Single release of HP Turbine Blade on more than one engine could result in
multiple engine loss of power or In-Flight Shut Down (IFSD). This event presents
a potential unsafe condition to the aircraft.
This Airworthiness Directive is published to require inspection of the HPT NGV
Convex Surfaces and, depending on the results, subsequent corrective actions."

Inspektion som ska utföras är:

"Required as indicated, unless accomplished previously:
Prior to achieving 400 total cycles, inspect the HPT NGV Convex Surfaces in
accordance with the accomplishment instructions in section 3.A of Rolls-
Royce RB211-Trent 900 Alert Non Modification Service Bulletin (NMSB) 72-
AF995 Revision 1.
If no damage is identified at first inspection:
- repeat inspections must be carried out at intervals not exceeding 100
cycles.
- if repeat inspections reveal no damage at 1 000 cycles revert to normal
inspection maintenance as detailed in the Rolls-Royce RB211-Trent 900
Maintenance Planning Document (MPD)."