The US Federal Aviation Administration (FAA) plans to issue a notice of proposed rulemaking (NPRM) on 5 August for Boeing 737-600, -700, -800 and -900ER models equipped with LiveTV's television service after reports of cracking in the radome assembly during inspections.
The proposed airworthiness directive would require inspections of the radome assembly and the installation of a new radome if required. The radome houses the antenna equipment for the satellite-based live television service.
The FAA says it received reports of cracking in 26 radomes on Boeing 737s modified with the LiveTV system under two STCs. If implemented, operators would be required to perform inspections of the radome within 1,250 flight hours after the airworthiness directive goes into effect and perform additional inspections within that interval. If a crack is found, airlines would have to send the inspection results to LiveTV.
LiveTV issued a service bulletin in March that recommended the inspection within 1,250 flight hours.
"Investigation of the cause of the cracks revealed that lack of dimensional controls on the radome manufacturing drawings can result in the introduction of preload stress on the radome during its assembly with the skirt fairing," says the proposed rule. "Preload stress combined with flight or handling stress, such as maintenance personnel stepping on the radome fairing assembly, might initiate a crack."
These drawings were revised in September 2010 to include these dimensions, the FAA document says.
These cracks could eventually result in the radome or its parts hitting the tail if it separates from the aircraft.
FAA estimates show that there are 165 aircraft registered in the USA with the modifications, with inspections costing $14,025 per inspection cycle. Replacement parts would cost $23,680.
The LiveTV customers operating Boeing 737s are WestJet and Virgin Australia and United Airlines, the last of which has indicated it plans to add Ka-band wi-fi offered through Live TV and satellite partner ViaSat on some aircraft.
The comment period for the NPRM will conclude 45 days after the filing appears in the US Federal Register, scheduled for publication on 5 August.
LiveTV could not immediately be reached for comment.