The two black boxes on missing Malaysia Airlines flight MH370 were never returned to their manufacturers although they were due for overhauls and battery replacements in 2012, CNN reported today.
Quoting the president of the pinger manufacturer Dukane Seacom of Sarasota, Anish Patel, the report said that this would leave three possibilities.
First, the airline could have replaced the old pingers with new ones, or it could have had another company perform the necessary maintenance, or it could have let the scheduled maintenance lapse – meaning the pingers would have a shortened battery life, the report said.
The battery life of the pinger would have dropped from the required 30 days to 20 or 25 days if the original battery had been used in the black boxes, Patel told CNN.
It said MAS did not respond to the network's query about the compliance of the pingers on MH370.
But it noted that in an earlier email last week about the airline's storage practices, MAS said: "We are unaware of any issue with the ULB (pinger) or its batteries."
"This battery is not replaceable," the airline had said. "The battery is built-in inside the (pinger) and installed by OEM – Original Equipment Manufacturer."
The National Transportation Safety Board had earlier informed Dukane Seacom that it manufactured the pingers on MH370's black boxes.
Patel said the devices were manufactured in late 2005 and late 2006 and were due for overhauls and new batteries in 2012.
"(But) we have no record of those units ever coming back for a battery replacement."
He told CNN that because the pingers were sealed, airlines typically return them to the manufacturer for battery replacement.
But airlines sometimes chose to have other companies do the work, or they replaced the pingers entirely, he said.
Patel said MAS used to send its pinger to Dukane Seacom for maintenance but it had not done so in the "last couple of years".
"Up until 2009, 2010, we used to see it on a regular basis. So they could have gone to another protocol such as doing it themselves, or they could have gone to another repair facility," he was quoted as saying.
MAS could have also let the maintenance lapse, he said. "Theoretically, they could have eight-year-old batteries," Pated said, reported CNN.
The report said that pingers are required to operate for a minimum of 30 days. To ensure that, manufacturers installed batteries that can last longer.
Patel told CNN that his pingers could work for up to 35 days or longer at full strength.
But, he said, the time span would decrease if the batteries were not replaced.
The pinger sound, which was inaudible to human ears, would not stop immediately after it surpassed its full-strength design life, but faded over time, CNN said.
Patel told the network that the pinger would continue to emit signals with "progressively lower output levels until the unit shuts down".
The aerospace company that manufactured MH370's black boxes said MAS had sent the cockpit voice recorder to Honeywell for an overhaul and modifications in 2006.
The company noted in its paperwork that the pinger, also called a locator beacon, was set to expire in 2012, its spokesman Steven Brecken was quoted as saying.
In 2007, the airline sent the flight data recorder to Honeywell after a cockpit light indicated there was a fault with the device, CNN said.
Honeywell, Brecken said, had performed a check on it and did not find any faults. It returned the device back to MAS after making sure it was "working 100%".
However, Honeywell has no record indicating whether the airline serviced the beacons as scheduled.
"We don't perform the maintenance on the beacons, that's up to the airlines," Brecken told CNN. – April 5, 2014.