Southwest Airlines' Boeing 737 aircraft will undergo modifications later this year to comply with a US Federal Aviation Administration (FAA) airworthiness directive that requires operators of some 737 models to install new cabin altitude warning lights in the cockpit.
The modification comes after a change in the design of the cabin altitude warning system that includes the installation of new components and wiring changes.
Receiving the modifications are 330 737-700s in Southwest and AirTran's fleets. The modification programme will be completed before a compliance deadline of March 2016, says the airline.
The modifications will take about 80 labour hours for each aircraft and will be completed during scheduled maintenance visits, says Southwest. The work entails installing and activating new cabin altitude warning lights in the cockpit, which includes modifying the existing instrument panels, installing the lights and then the required new wiring kit.
Assisting with the modification in Dallas is Irish engineering firm Eirtech Aviation, which says it has come up with a solution to reduce installation time and price by half when compared with other alternatives.
This is achieved by avoiding the routing of the wiring in zones of the aircraft that would require extensive changes to the systems already in place, says Eirtech. Southwest says this method will provide "significantly lower costs" than the alternatives.
FAA airworthiness directive 2013-02-05 went into effect on 6 March 2013. In that document, the FAA estimated that 870 aircraft registered in the USA would be affected by the AD.