takata, the IB and AF flights following AF447 reported repeated difficulty in contacting Dakar. I understood the three queries to Dakar ADS-C between 1:33 and 2:01 to be automated.
AF459
On leaving the ATLANTICO FIR, through the TASIL waypoint, the crew attempted in vain to contact Dakar control in HF on the 5565 KHz and 6535 KHz frequencies, and on the other HF frequencies given in the on-board documentation. Likewise, the attempted ADS-C connection was unfruitful.
The crew returned to the airway around the ASEBA waypoint, that is to say more than 28 minutes after the first theoretical contact.