EASA Reports
EASA_EAD 9/20/2013
EASA stated that a technical investigation reported that cracks in a MS21042L4 nut connecting a Thomas coupling with the splined adapter on AW100SP helicopters were believed to have been caused by hydrogen embrittlement.
EASA_EAD 10/30/2013
EASA stated that two MS21042-4 nuts connected to the swashplate support to the upper case of the main transmission of a A190S helicopter were found cracked. They stated the nuts in use were deficient with evidence of hydrogen embrittlement.
EASA_EAD 5/02/2014
Observed a cracked MS21042L4 which connected a flexible coupling with the coupling adapter on a AB 206 helicopter. EASA stated the deficiency was due to hydrogen embrittlement.
EASA_EAD 5/07/2014
EASA expanded the EAD above to include AB 212, AB 412, and AB 412EP helicopters.
EASA_EAD 5/13/2014
EASA expanded the EAD to include MS21042-5 nuts found on the flexible coupling. Pictures are included showing the location of the cracked nuts.
Plus NZ CAA June 2010.
Robinson R22 Jan 2014.
CASA Australia Sep 2014.
..and on and on.
Last edited by Gemini Twin; 31st Oct 2014 at 17:45.
Reason: typo.