The comment period for the FAA’s MOSAIC NPRM ends in a few days, on January 22nd. The Experimental Aircraft Association has recently released guidance for others interested in submitting comments. We encourage you to review the NPRM and comment. This document summarizes Van’s Aircraft’s thoughts on the EAA’s guide in two areas: noise and stall speed. Overall, we are in agreement with comments made by the EAA.
The FAA’s MOSAIC NPRM is located here: https://www.regulations.gov/document/FAA-2023-1377-0001
To comment on the NPRM, look for the “Comment” icon then follow the instructions provided at the link above.
If you do comment, please start by thanking the FAA for taking on this project. It is the most revolutionary change in a generation for aviation. The FAA has expended a considerable amount of energy and thought to harmonize a rule change that touches branches across the organization. The FAA, manufacturers, and public all realize the importance of general aviation as a foundation to our aviation infrastructure. We all want safer, affordable aircraft that will attract the public to become pilots and continue to enjoy aviation as we do. Considering the magnitude of this project, the FAA came close to the mark for a first proposal. We encourage everyone to acknowledge this as part of any comment to the NPRM.
Please note that the proposed rule will affect customers in two primary ways by defining what a light sport pilot can fly and what light sport manufacturers will be able to produce in the future. Although we commend the FAA on this groundbreaking proposed expansion, there are some areas that need further public comment. Van’s Aircraft will be releasing our own comments over the remaining days of the NPRM comment period. We also will be going into further detail beyond what is mentioned below.
First, let’s take a look at noise. As currently proposed, the rule includes strict noise limits and testing requirements. It is important to note that these noise limits, and related requirements for testing and compliance, would apply to all LSA aircraft as specified in 22.175. In other words, these requirements would apply to both ELSA and SLSA aircraft.* As a result, during the initial application for airworthiness, an ELSA would need to comply with burdensome noise limits and testing requirements. Also, if an ELSA aircraft made a change to their aircraft which would affect the noise signature, they would be required to submit an amended statement of compliance after successfully conducting additional, burdensome noise testing showing compliance with part 36 noise requirements.** As written, the rule would place a significant burden on the builder and FAA without a demonstrated benefit. As we all know larger aircraft and helicopters (which are allowed to operate at higher noise levels currently under part 36) are the real issues that drive noise complaints. The FAA has not provided data that supports that experimental or LSA aircraft make a significant contribution to noise complaints.
The FAA proposal applies part 36 noise requirements on all aircraft without type certificates.*** Although the rule makes clear that aircraft certified under 21.191(a) through (h) or (k) are exempt, on page 47714 the FAA makes the following request:
“The FAA requests comment on whether any categories of aircraft should or should not be subject to part 36 noise requirements, including any technical or economic data that support the comment.”
Van’s Aircraft agrees with EAA and will be commenting in response to the above question that all experimental ELSA or EAB aircraft should be exempt from noise requirements and testing. Testing would burden the FAA, increase costs, and not address the real noise issues we face. By clarifying this policy for ELSA today we will also be defending EAB tomorrow.
If noise testing is required for SLSA aircraft, the FAA’s methodology of using consensus standards should be used for demonstrating compliance. The NPRM as written would require FAA oversight. Currently, certified manufacturers have difficulty scheduling noise tests with the FAA. Existing SLSA and ELSA designs being sold today would need to show compliance before airworthiness certificates are issued. The backlog with well over a hundred SLSA manufacturers scheduling tests with the FAA would “pause” the light sport industry for an unknown duration. This would not be economically viable for many LSA manufacturers. A system using consensus standards would reduce the cost and burden on the FAA.
Next, let’s take a look at stall speed. The NPRM currently proposes a clean stall speed of 54 KCAS Vs1. This would allow a sport pilot to fly an older, previously built, two-place RV. However, these RV aircraft (and some legacy aircraft certified to CAR standards), do not meet the current design requirements for LSA aircraft. So, as currently written Van’s Aircraft would not be able to produce any of its legacy two-place aircraft under MOSAIC. In addition, the clean stall speeds of the RV-14 and RV-10 aircraft are 61 KCAS and 65 KCAS respectively. So, as things stand, no Van’s RV aircraft would be able to be produced under this proposal. One of the stated hopes of the NPRM is that: “The increased utility of light-sport category airplanes may also improve safety by providing aircraft owners with an attractive alternative to experimental amateur-built aircraft.” Simply put: without a change in the currently proposed stall speed, the most popular amateur-built aircraft will not be included in this expansion of light sport. Van’s Aircraft believes that changing the stall speed to 54 Vso with the use of conventional flap systems would be acceptable. A better solution would be 61 Vso (which was already deemed safe in the preamble for the Primary category decades ago). 61 Vso is already in use by foreign countries where MOSAIC is already in place, and should be considered for harmonization between markets. We will explore these possibilities in further communications.
The FAA when looking at this category of aircraft considers the safety continuum. Higher privileges result in higher risk of exposure, which results in higher certification rigor. Currently, there is a significant difference in the requirements (and costs) to certify a light-sport aircraft using consensus standards versus those required to certify an aircraft using the primary category or Part 23. The certification requirements for type certificated aircraft are extremely high, and over the last 20 years, very few aircraft in the 2-4 seat piston powered (affordable aircraft) market have been certified in these categories. This has resulted in stagnation of new designs being introduced to the market and escalating costs. Most importantly, this level of certification has stifled innovation which will leave the United States falling behind as new innovative products are developed worldwide. Instead of one large step up in requirements, smaller steps would allow MOSAIC to bridge the gap between the current 54 KCAS Vs1 proposal and type-certified world.
The EAA has proposed an increase to 58 KCAS. This slight increase in stall speed will help include several older certified aircraft, allowing an expansion in sport pilot privileges. In addition, they propose a method of allowing manufacturers to certify aircraft with higher stall speeds with the addition of additional safety enhancements. Van’s Aircraft endorses the language proposed by EAA to allow the FAA the flexibility to consider additional safety enhancements as a means of allowing an expansion beyond the minimum Vs1 limit. Although Van’s Aircraft would prefer 61 KCAS Vso, we agree the rule at minimum should be changed to 58 KCAS Vs1 and include the additional language proposed by the EAA of: “unless the aircraft meets additional crashworthiness requirements or has safety enhancing features.” These additional safety features would be detailed in consensus design standards which are accepted by the FAA as a means of compliance to the proposed rule. Many of the proposed safety features are already included in RV’s and modern avionics, which would reduce the cost of an aircraft meeting these additional requirements. If an airplane added additional safety features a higher stall speed would be allowed. Van’s Aircraft supports this extension of the safety continuum using consensus standards without a type certificate.
Overall, we are encouraged by the guidance published by EAA. We approve of their viewpoints including the other topics covered such as sport pilot privileges, night operations, and maintenance. Stay tuned as we will continue to communicate.
* NPRM Page 47710 8.b.
**The proposed 36.1581 (page 47729) would require compliance be documented per 21.190(e). Although 21.190(e) currently only mentions aerial work it is also the intent of the proposal that after an ELSA aircraft was modified the owner would need to amend the 8130-15 form to show compliance the noise requirements. If an ELSA owner made a change that affected the noise signature of the aircraft they would need to conduct noise testing. A change to the noise signature could be something as simple as the addition of wheel pants or aerodynamic change or the more obvious engine or propeller change.
***As specified on page 47729 of the NPRM in 36.1 (7) and 36.0 (d).