Originally Posted by
Apate
If anyone has access to the original accident report for 9M-SSC, they will see an Addendum containing a statement from Eurocopter that they did not agree with the root cause finding of the report. Some things never change!
Yep, they did it then and looking at the recommendations in REDL's report, you have to ask whether they complied/accepted fully then too. (See recommendations below first quote)
In Appendix 1 to the report, the manufacturer (at that time Aerospatiale) made various comments, some of which are included below:
‘….the assumption of the box bursting as the accident first cause is negated by the following.
-- No fragments of the missing second stage [planet gear] have been found
-- Relatively correct condition of high speed stages, which should have shown epicyclic gear jamming marks (especially on flexible couplings and torquemeter shafts)’
-- When a planet gear rupture generated by its race chippings occurs, it is necessarily preceded by the initiation of fatigue cracks through the rim
4 Safety Recommendations
4.6 Safety Recommendation 2009-075: It is recommended that the European Aviation Safety Agency, in conjunction with Eurocopter, urgently review the design, operational life and inspection processes of the planet gears used in the epicyclic module of the Main Rotor Gearbox installed in AS332 L2 and EC225LP helicopters, with the intention of minimising the potential of any cracks progressing to failure during the service life of the gears.
4.11 Safety Recommendation 2011-036: It is recommended that the European Aviation Safety Agency (EASA) re-evaluate the continued airworthiness of the main rotor gearbox fitted to the AS332 L2 and EC225 helicopters to ensure that it satisfies the requirements of Certification Specification (CS) 29.571 and EASA Notice of Proposed Amendment 2010-06.
4.14 Safety Recommendation 2011-043: It is recommended that Eurocopter introduce a means of warning the flight crew, of the AS332 L2 helicopter, in the event of an epicyclic magnetic chip detector activation.