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A look at advancements in cellular telephone communication, data recorders, and emergency locator transmitters


Even passengers and crew on business aircraft will soon be able to use their own 802.11b/g equipped WiFi data devices including laptops, PDAs, and BlackBerrys in flight. Aircell broadband is currently expected to be available to general aviation in the third quarter of 2008. This service will be available with Aircell Axxess equipment and is expected to provide DSL broadband speed in a wireless environment.

Inmarsat is another leading space-borne phone service provider and owns and operates a fleet of commercial mobile communications spacecraft, flying in geostationary orbit, 35,786 km (22,240 statute miles) above the Earth.

This includes two of the latest generation satellites, the Inmarsat-4s (I-4s), which were launched in 2005. They currently provide coverage to around 85 percent of the world’s landmass and 98 percent of the world’s population. This level of technology enables service providers to charge subscribers only for data sent and received via packets versus airtime. This makes the traditionally expensive service very cost effective. In some cases existing high-speed data (HSD) equipment can be upgraded to enable the broadband capability.

Inmarsat is also planning to launch a third I-4 satellite in 2008 which will deliver complete mobile broadband coverage of the planet, except for the extreme polar regions.

Data recorders
Data recorders were another thought that crossed my mind as a possible interesting topic.

The Federal Aviation Administration (FAA) has mandated significant upgrades to aircraft cockpit voice and flight data recorders. These improvements will enable investigators to retrieve more data from accidents and incidents requiring investigation.

Under the final rule, which affects manufacturers and operators of airplanes and helicopters with 10 or more seats, all voice recorders must capture the last two hours of cockpit audio instead of the current 15 to 30 minutes. The new rule also requires an independent backup power source for the voice recorders to allow continued recording for nine to 11 minutes if all aircraft power sources are lost or interrupted. Voice recorders also must use solid-state technology instead of magnetic tape, which is vulnerable to damage and loss of reliability.

Airplanes (but not helicopters) operating under Parts 121, 125, or 135 of FAA regulations will have to retrofit some equipment by April 7, 2012. The rule also mandates these enhancements on all newly built aircraft and helicopters after April 7, 2010.

The new rule also requires that the recorders measure aircraft data more frequently and includes the aircraft’s primary flight control movements along with the pilots’ input to the controls. Compliant data recorders must be able to retain the last 25 hours of recorded information.

The final rule formalizes current FAA policy that voice and data recorders must be housed in separate units (excluding helicopters) and that no single electrical failure can disable the units. It does become acceptable for operators who install two combined voice and data recorders to mount one of those combined recorders in the forward part of the aircraft. Details of the final rule can be found at: http://www.faa.gov/regulations_policies/rulemaking/recently_published/.

Prescribed maintenance and testing of data recorders has been somewhat of a vague area especially for general aviation. Advisory Circular AC 20-141 defines a functional check as a quantitative check to determine if one or more features of an item perform within specified limits. When applied to a DFDR parameter, the functional check determines that the recorded parameter is within the limits (range, accuracy, sampling rate, and resolution) specified in the operating rule. The applicant for a Supplemental Type Certificate (STC) must accomplish a functional check for all mandatory parameters for the “first of type” installation testing then must perform the “first of type” installation testing for an FAA approval. During the “first of type” functional check, it may not be feasible to stimulate some sensors to their specified limits. In such instances it is acceptable to simulate the sensor output using suitable test equipment. The operator must include a different functional check in the maintenance program. This maintenance functional check applies to those parameters that can neither be read out during the flight data download, nor functionally checked as part of other aircraft systems. The maintenance functional check may simulate sensor or transducer outputs to check the range, accuracy, resolution, and sampling rate of the recorded data. However, the instructions for continued airworthiness and the operator’s maintenance program must prescribe a periodic functional check of each of these transducers or sensors for accuracy and range.

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