ATM Modernization, Business & GA, Embedded Avionics

FAA Improves Clarity of ADS-B Avionics Regulation

By Woodrow Bellamy III  | February 11, 2015
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[Avionics Today 02-11-2015] The FAA has issued a technical amendment to the final rule published back in 2010 defining regulations for equipage requirements and performance standards for Automatic Dependent Surveillance-Broadcast Out (ADS-B Out) avionics on aircraft operating in Classes A, B and C airspace as well as other specified classes of airspace within the National Airspace System. Under the technical amendment to the ADS-B Out rule, the agency is correcting any confusion that existed with the regulatory provisions addressing ADS-B Out equipment and use. 
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Owners of light sport aircraft, such as the ICON 100 pictured here, will benefit from the clarity of the technical amendment to the ADS-B rule when deciding to equip to comply with the Jan. 1, 2020 mandate. Photo: ICON.
In the 2010 final rule the FAA established section 91.225, which defines ADS-B equipment requirements necessary to fly in airspace that requires a Mode C transponder today. Section 91.225 sates that, in order to operate an aircraft in Class A airspace, an aircraft must have installed avionics that meets the requirements of Technical Standard Order C166b (TSO-C166b). That rule also requires aircraft operating below 18,000 feet MSL and in identified airspace subsequently in 91.225, an aircraft must feature equipment that meets the requirements of TSO-C166b or TSO-C154c.
The technical amendment to this rule published on Feb. 9, states that the FAA is amending 91.225 to reflect that aircraft must feature equipment that meet the necessary performance requirements but not the actual type certification requirements of the TSO. Doug McNair, vice president of government regulations for the Experimental Aircraft Association (EAA), told Avionics Magazine that the rule change will have the biggest impact on the experimental aircraft and light sport aircraft sectors of the General Aviation (GA) flying community. 
“This is a relatively minor change but it is foundational to some of the work we are going to continue doing with the FAA,” McNair said. “Avionics for experimental aircraft including amateur builds, historically have not been required to carry a specific TSO [compliant] device — they could carry avionics that meet the performance requirements of the TSO, but they themselves might not be TSO [compliant]. That’s true of things like transponders, altitude encoders and a variety of other air traffic dependent avionics. When the rule was written for ADS-B, the specific word performance was left out and that is important only because as the rule was written it would have required TSO [compliant] devices.”
The FAA noted in the technical amendment that, upon publishing the 2010 ADS-B Out rule, it was not looking to limit operators to “only install equipment marked with a TSO,” but rather to permit the use of avionics that “meets the performance requirements set forth in the referenced TSOs.”
By changing the language for the equipment requirements, the ADS-B Out rule is now reflective of other avionics rules where performance language is common, such as that included throughout Part 91 Subpart C (Equipment, Instrument and Certificate Requirements), according to Ric Peri, vice president of government and industry affairs for the Aircraft Electronics Association (AEA). 
“If I could turn the hands of time back about five years, I would suggest a single product TSO that was all encompassing for [Universal Access Transceiver] UAT and [Wide Area Augmentation System] WAAS rather two separate TSOs,” Peri told Magazine. “While the TSO as written really supports transport category aircraft very well, the ‘systems’ approach that the FAA took for ADS-B could have been better as a product standard for Part 23.”
While the rule change now provides more clarity, it is difficult to measure exactly how it impacts many aircraft and operators. According to McNair, there are nearly 30,000 GA aircraft that can be categorized as experimental, amateur or “home build” type of aircraft, which typically do not feature type certificated avionics. But whether or not an aircraft actually needs the installation is based upon the type of flying that operator does today, and wants to continue doing in 2020 and beyond. 
“It is hard to say what percentage of that fleet would want to install ADS-B, that hinges on where you want to fly,” said McNair. “I envision that aircraft that currently has an encoding altimeter and a Mode C transponder, chances are if you have that equipment in your aircraft today it’s because you fly in that airspace and that is the very same airspace where ADS-B is required. It’s hard to get a fixed number on how many installations there will be but it’s a fairly sizeable percentage of the fleet.”
Now that there is more clarity in the equipage requirements for the experimental aircraft community, the main issue going forward will continue to be the cost of installation and equipage, McNair said. 

“As we work with the Equip 2020 group, we are exploring ways that can potentially bring down the cost of ADS-B. Time is getting short but we are certainly exploring some creative ideas of ways that we are hoping we can leverage volume or technology to bring the cost of compliance down,” he added. “We support broad based adoption of ADS-B, we think that’s integral to the future of the air traffic system but the price is too high right now, we are being told that loud and clear by our membership. Much of our effort is geared toward trying to find creative ways working with industry to lower the price point and availability and thus the adoption rate.” 

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