Air France Flight #447 crashed on June 1, 2009 over the Mid-Atlantic in very deep water. Debris was found within days but the black boxes could not be found within the 30 days battery life of the underwater locator beacons (ULB’s). It took 2 years to find the underwater locator beacons due to the difficult terrain and extreme depth.
BEA (Bureau d‘Enquêtes et d‘Analyses) immediately initiated a drive to extend as rapidly as possible the regulatory transmission time for ULB’s installed on flight recorders on aircraft performing public transport flights over maritime areas to 90 days.
As a result, a committee of aviation and ULB experts was formed under the umbrella of ARINC. They created the SAE AS8045A as a baseline for a new TSO (Technical Standard Order) which the FAA released in 2012 under TSO-C121b.
The new TSO- C121b is effective March 1, 2015 and requires all new ULB’s manufactured as of that date have a 90 days battery life and meet the TSO’s technical and testing requirements. The testing requirement also requires batteries to be tested in accordance with TSO-C142a.
TSO-C121b further stipulates that previous TSO’s for 30 day beacons (TSO- C121 and C121a) will automatically be withdrawn, effective February 28, 2015.
After consulting with a number of experts, we interpret this to mean that no Airworthiness tags can be issued against the old TSO’s after February 28, 2015.
EASA issued Opinion No. 1 in 2014 requiring all aircraft in CAT to switch to 90 day beacons meeting TSO-C121b as of January 1, 2018.