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AIR TRACTOR INC. P. 0. BOX 485 OLNEY, TEXAS 76374 

Friday,April29,2016 

Docket Operations 

M-30 

US Department of Transportation 

1200 New Jersey Avenue SE 

940-564-5616 940-564-5612 (FAX) 

Room W12-140, West Building Ground Floor 

Washington, DC 20590-0001 

Docket No.: FAA-2015-1621 

Docket Name: Part 23 Reorganization 

Mr. Lowell Foster, and the FAA, 

We appreciate the intent ofthe FAA's proposed Part 23 Reorganization rules with respect to 

decreasing the costs of certification and enhanced safety. Nevertheless, the rule changes that are 

proposed are sweeping, affecting Parts 21, 23, 35, 43, 91, 121, and 135, and it is not possible for 

us to adequately review or address the proposed new rules for their potential impact to our 

industry (helpful or detrimental), or the general aviation industry as a whole, within the allocated 

comment period of 60 days. Therefore, we request that you please extend the comment period 

for at least another 180 days to provide time for adequate technical review and comment, on this 

complex subject. , 

The regulations and policies affected by these proposed changes are technical in nature. 

Therefore, we recommend that comments from the Designated Engineering Representative 

(DER) community be purposefully pursued and collected to the maximum extent possible. 

As we have numerous comments to the proposed changes, we offer the following philosophical 

points as a basis from which a more positive solution-based discussion could begin, based on our : 

company's more than 50 years of operation and cooperation with the FAA in the design, 

certification, and manufacture of more than 3,000 airplanes that are currently operating all 

around the world. 

Philosophy: Current Impediments to Rapid and Economical Airplane Certification 

The primary factors that make the current certification process lengthy and expensive (and 

frustrating) are ... 

1. The time and resources that must be spent negotiating with the FAA to obtain 

agreement/approval to proceed with certainty; 

2. The time and uncertainty that is injected into the middle of a project while waiting for the 

FAA to review/evaluate/approve submitted work, before further work can be 

accomplished; and 
April29, 2016 Part 23 Reorganization 

FAA-2015-1621 

3. The difficulty of the qualification process for non-required or non-safety-related 

equipment items. 

page2 

The certification process is a gated process. Certain steps must be accomplished before other 

steps may be carried out. In the current process the FAA controls the gates which allow the 

applicant to advance to the next step. This gated process is prominent at the beginning of a 

project when the Project Specific Certification Plan (PSCP) is submitted. But then later in the 

project it is typical for the FAA to remain involved at various points in most pieces of the 

certification effort. That is, there are lots of gates throughout the overall process in which it is 

necessary to obtain FAA approval or acceptance. A significant disagreement at any one of these 

points causes the entire project to stall. In most cases these potential pinch points are not 

foreseeable at the beginning of the project, despite our best efforts to plan appropriately when the 

PSCP is worked out. 

For example, the FAA typically reserves for itself the approval of aerodynamic loads reports. 

The FAA itself generally does not have aerodynamic loads experts on staff at each Aircraft 

Certification Office (ACO), but there are Designated Engineering Representatives (DERs) 

available that are experts in this field, and are generally employed by the applicant for this type 

of work. Still, the FAA local office holds up the approval of these documents until someone at 

the local office has reviewed the DER's work. The results of such loads definitions efforts are 

needed before significant structural design, analysis, and approvals can be obtained. 

In another example, the FAA typically reserves for itself the approval oftest plans. The proper 

planning of tests is important for the test results to be valid at the end of the process, but it can 

delay the downstream test efforts by months while the FAA is brought up to speed on the details 

of a project and test, comments on the proposed test are discussed and debated, and the test plan 

is approved. In almost every case the test plan was already reviewed by a DER (an expert in that 

field, by judgment of the FAA), who recommended approval of the plan, but still the FAA 

requires that it be involved in reviewing and approving the plan. There is uncertainty on the part 

of the applicant as to whether or not test fixtures and equipment should be manufactured or 

procured if the test plan has not yet been approved (it could change), so the gated approval 

process slows the pace of the project. If the FAA requires significant changes, the planning 

process has to go back and address whatever changes the FAA felt were necessary, then go back 

through the review and approval process to move on. 

In one more example, the FAA typically reserves for itself the approval of system safety 

analysis. The process of system safety analysis used in the design and development of airplanes 

is complex, with many steps, and each step is subject to a significant degree of subjective · 

appraisal. The original plan to employ such analysis was to aid the designer in the design of 

systems that addressed the various safety pitfalls within any particular design, but as currently 

employed the safety analysis aspects of a new airplane design typically start before the project is 

kicked off and is one of the last things to be completed prior to certification. There is so much 

required FAA review and approval that there are ample opportunities for disagreements that can 

delay or stall a project. 

There are other situations that occur in every airplane certification program which inject 

uncertainty and time into the process, all of which are due to the need for direct FAA 

involvement and decision-making during the process. 
April29, 2016 Part 23 Reorganization 

FAA-2015-1621 

page3 

Although it has been considered significant that various Light Sport Aircraft (LSA) have 

achieved certification with rapidity using ASTM F2245 and its other associated standards, we 

believe that the real improvement in the process is the minimization of direct FAA involvement. 

It may be that some rules should be changed in ways that would be more of a common-sense 

approach. And some rules probably should not be applicable to some kinds of airplanes. But for 

the most part, the difficulties that our company has had with airplane certification has not been 

about the burden of showing compliance to unreasonable rules. Rather, it is about the 

unreasonableness that is associated with the differences between one human being and another 

that represents the FAA. These differences add uncertainty and variance to the overall process, 

and in the end it takes longer and costs more. 

This whole rule change movement was originally about trying to reduce the time and expense 

associated with airplane certification. We completely agree that this is a problem that is critical 

to our industry, and that solving this problem is an objective worthy of time and effort. But, for 

the most part, we believe that the proposed rules will increase the time and costs associated with 

airplane certification. 

From the review ofNPRM FAA-2015-1621 that we have conducted so far, we have the 

following comments. Page references correspond to the 283-page PDF version of the NPRM 

that is referenced above. 

Representation 

1. No person from the agricultural aircraft industry was represented on the ARC (Aviation 

Rulemaking Committee, seep. 14). 

With regard to assessing the impact on small firms (p. 173, Chapter VII, Regulatory 

Notices and Analyses, section B, Initial Regulatory Flexibility Determination, Item 5, 

Estimated Number of Small Firms Potentially Impacted), Air Tractor and Thrush were 

left out of the FAA's analysis. 

Both of these manufacturers use Part 23 as the primary portion of their certification 

bases. These manufacturers combined for 182 aircraft deliveries in 2014, totaling over 

$100 million in sales. At least one of these manufacturer's has an open project to certify 

an airplane to the existing Part 23 regulations. 

2. Analysis concerning the impact on small firms (p. 173) ultimately included data from 

only 5 firms, one of which has not been in operation for 8 years (Adam Aircraft), and 

another that no longer exists, but is struggling to set up business under new ownership 

(Sino-Swearingen, then Emivest Aerospace, and now SyberJet). It would seem that the 

FAA should have knowledge of every company that still has active manufacturing 

activities (active production certificates), and that the data that was included was 

exceptionally non-representative of the overall industry. Further, by eliminating from 

consideration all firms that are not US-owned a distorted view of the true impact on the 

general aviation industry in our country is presented. 

In addition to American Champion, Maule, and Quest, several small companies that 

continue in business, and have made aircraft deliveries, were not included in your 
April29, 2016 Part 23 Reorganization 

FAA-2015-1621 

page4 

analysis. Among these would be Air Tractor (Texas), Angel Aircraft Corporation (Iowa), 

Cirrus Design (Minnesota), CubCrafters (Washington), Eclipse Aerospace (New 

Mexico), The King's Engineering Fellowship (Iowa), Mooney (Texas and California), 

Piper Aircraft (Florida), and Thrush (Georgia). There are probably more. Although 

some of these companies are no longer US-owned, they all continue to operate within the 

United States for primary aircraft certification activities, to the certification standards of 

the United States, and are handled by the FAA for certification support in the same 

manner as any US-owned entity. Virtually all of them are actively designing new 

products, or making amendments to existing type designs, and therefore have a vested 

interest in this rule change. 

It is noted that just by the inclusion of only the two companies that manufacture restricted 

category agricultural airplanes (Air Tractor and Thrush), both US-owned companies, the 

number of employees and annual revenues represented in your analysis would be 

doubled. 

It is noted that Cirrus was represented on the ARC, but was excluded with respect to rule 

impact because of its foreign ownership. The impact analysis seems to be significantly 

flawed. 

3. A review ofthe FAA's list of Type Certificate Data Sheets shows that there are hundreds 

or thousands of TC Holders for Small Airplane products. Whether or not these type 

designs are being actively manufactured, they must still be supported by the TC Holder. 

The scope of affected small businesses was not adequately addressed. 

4. There are a large number of STC Holders that certify products to the Part 23 rules, and 

are active manufacturers. The effect on these companies was not considered in your 

analysis. 

5. It is noted that Tamarack Aerospace, who was represented on the ARC (seep. 14), and 

who is in the business of designing and certifying load alleviation devices, has secured 

accommodation for devices of their type in the regulations (see proposed §23.305). 

Considerable space was afforded in the discussion (pp. 81-84) to lobby for the inclusion 

of such devices in a manner that maximizes their utility to the industry. We do not 

oppose the inclusion of such devices, but it would appear that having had representation 

on the ARC may have afforded direct benefit to its participants. Conversely, lack of 

representation may prove detrimental for our company. 

6. The effects on the certification of restricted category aircraft were not addressed and no 

work has been done to establish an appropriate means of compliance standard. Today 

most agricultural or other restricted category airplanes are certified to the rules of Part 23, 

with certain rules deemed not applicable per AC 21.25-1. 14 CFR §21.25 establishes the 

restricted category, but our industry continues to rely heavily on Part 23 to establish 

certification requirements. Is there still a home for restricted category aircraft under the 

proposed Part 23? 
April29, 2016 

General Comments 

Part 23 Reorganization 

FAA-2015-1621 

pageS 

1. With respect, we find the following FAA comment (from the top ofp. 10) regarding costbenefit analysis to be vacuous: 

"If the proposed rule saves only one human life, for example, by improving stall 

characteristics and stall warnings, that alone would result in benefits outweighing the 

costs." 

By the standards of that statement the cost-benefit balance for outlawing all forms of 

motor vehicles (and bicycles, and skateboards) would be justified. 

We believe that our industry places a very high value on protecting human life, and 

expends enormous energy, talent, and resources to protect it. In the past the regulatory 

environment has made it difficult to implement innovative solutions, wherein the FAA 

certification process was the impediment to progress (not necessarily the rules). The 

FAA needs to understand that mandating the changes that are contained in these proposed 

rules (such as departure resistance) generally will not help applicants achieve 

certification; they will instead make it more difficult to obtain certification, and thereby 

impede the development and certification of new airplanes with these favorable 

characteristics. 

2. It is recommended that all references to alternate metric units be removed. Their 

existence opens the door to misinterpretations about precedence when the alternate value 

shown is not an exact conversion (and it almost never is). For example, takeoff 

performance data per §23.115(b) to an altitude of 50 feet (15 meters). Use of an exact 

15-meter height would round to 49 feet. 

3. We don't see a big difference in the certification effort required for the different Levels 

and Speed classes. Maybe there is a big difference in required levels of safety for 

equipment, but that is impossible to tell because the FAA has not decided what those 

levels of safety will be (see proposed §23.1300). 

It should be noted that the preamble material accompanying these proposed rules will not 

be given the weight oflaw. Uncodified good intentions stated in the preamble are of no 

lasting value. 

4. The new certification process will create a "hidden certification basis" for TC'd products, 

composed of the regulations and the means of compliance. A person who did not 

participate in the certification process will not know how that aircraft was certified, 

because those certification requirements that were previously disclosed in the prescriptive 

regulations will now be hidden behind private negotiations with the FAA in the means of 

compliance agreements. Imagine trying to obtain an STC for a TC' d product without 

knowing what maneuvering or gust load factors were deemed necessary for the product 

during its initial certification. 

It may be that the would-be STC holder has no right to know that information, but hiding 

such information will tend to stifle the approval of STCs apart from a cooperative TC 

holder, and thereby it will slow the approval of third-party STCs from which most 

electronics and safety-related innovation has come. 
April29, 2016 Part 23 Reorganization 

FAA-2015-1621 

page6 

5. On p. 39 (last paragraph) it says the proposed changes to 14 CFR §21.9 will allow 

manufacturers of replacement or modification articles of non-required safety-enhancing 

equipment (whose failure would not cause a hazard) to obtain production approval from 

the FAA without obtaining an FAA design approval for that equipment. Historically, this 

emphasis of fast-tracking non-required safety-enhancing equipment approvals has not 

applied to OEMs that want to install the same equipment. Will the proposed changes to 

§21.9 apply equally to a TC holder that wants to install this type of equipment without 

design approval for the equipment? We believe that STC applicants and TC applicants 

should be treated equally. 

Consensus Standards 

1. We do not agree with the proposition that removing the prescriptive regulations will 

make for a simplified certification process (reference p. 20, the last paragraph of Chapter 

III, Section C). For standard configuration aircraft, the prescriptive regulations are the 

simplest regulations to meet because there is a definite pass/fail criteria. It is the vague 

and general regulations that are more often the regulations that require complex FAA 

involvement because there is no agreement on what the pass/fail criteria is. 

2. Removing the prescriptive regulations is going to allow for much wider disparities 

concerning what is an acceptable showing of compliance. Some applicants will be held 

to high standards, while others will be required to meet a lesser standard, because of the 

combination of ... 

a) What the applicant proposed; and 

b) What FAA local personnel felt was necessary. 

Both of the above are significant variables. The former depends significantly on the 

applicant's knowledge, sense of prevailing expectations, and negotiating skills. The later 

depends on the reasonableness and knowledge of the specific FAA personnel that are 

involved. 

For airplanes of standard design the existing rules are generally adequate. When there 

are non-standard design features, or the rules are deemed inadequate or inappropriate, our 

existing system has a means of addressing such things through the issue paper process. 

This is a slow, tedious process that should rightly be avoided. Yet it would seem that the 

proposed plan to rely on consensus standards for showing compliance to most rules will 

require the Applicant and the FAA reach an agreement on an acceptable means of 

compliance for every rule, even for airplanes of standard design. From page 24, the last 

sentence of paragraph 1, "The process for reviewing new means of compliance would not 

change substantially from the process in place today." This has the potential to function 

like having hundreds of"mini issue papers" for every new project. 

We believe that the FAA already knows about, and appreciates, the extra delay and drag 

that will be incurred during the process of negotiating a PSCP for a new project, but 

under the mandate from Congress to reduce the time and cost to certification is willing to 

allow the prevailing optimistic philosophy to play out to reality. In the discussion for 

§23.10 regarding "Accepted Means of Compliance" on p. 51, the FAA felt compelled to 

warn, 
April29,2016 Part 23 Reorganization 

FAA-2015-1621 

page? 

"Additionally, the FAA wants to ensure applicants understand that an applicantdeveloped means of compliance document would require FAA review and acceptance by 

the Administrator." 

For a sense ofhow tedious and obstructive this process can be, our company proposed a 

new airplane design to the FAA in October 2002, for which a G-1 issue paper was written 

to establish the certification basis. This issue paper was not completed until May 2010 

7ih years! Even then, a smaller issue regarding compliance to three Part 23 rules needed 

to be worked out in an A-1 issue paper that took another 2 years to resolve. This process 

of recorded back-and-forth between the Applicant and the FAA showed us that the FAA 

does not always have a good understanding of its own rules or the expertise at the local 

level to work out reasonable means of showing compliance. It took a lot of negotiating to 

work out rules that were even somewhat reasonable. 

When this negotiation occurs project-by-project the results will be highly variable, 

consume enormous time and resources from both the FAA and the Applicant, and make it 

impossible to design a new airplane with knowledge of what is expected for certification. 

(Most airplanes are designed to a significant degree before their certifications are 

proposed to the FAA.) 

If these negotiations are handled by a single group of people at the FAA there will likely 

be more parity between projects, but now there will be a bottleneck in the process as 

every company in the country needs to negotiate through this one group. 

We have heard that ASTM standards, as well as some other standards, are going to be 

acceptable means of showing compliance. The assumption seems to be that the FAA will 

publish the list of accepted standards and that, as policy, FAA certification specialists 

should accept these standards without question. But we do not see a clear plan to 

implement this as regulation or policy. We expect that during the negotiation process to 

set the certification basis for a product that each specific MOC that is proposed by the 

applicant will need to be reviewed by the FAA local office to determine if it is 

appropriate for the proposed product. Even if the applicant elects to use pieces ofF AAaccepted ASTM standards for every proposed MOC, this review process will take more 

time, not less. 

For aircraft of non-standard configuration that would already be subject to the issue 

paper process - the new process may not be much different, even if increased flexibility 

is available. But most aircraft are not that unusual. Under the new process, for aircraft of 

standard configuration it will take almost as long to hammer out a certification basis as 

would be needed for an existing airplane of non-standard configuration. This doesn't 

seem like progress. 

The most time-consuming and frustrating aspect of certifying a new airplane is 

establishing the certification basis and obtaining approval of the PSCP (project specific 

certification plan). Ordinarily this is a negotiation between the applicant and the FAA for 

every project, which can last from several months to several years. Under the new rules 

virtually every rule will require that the language for the means of compliance must now 

be negotiated, which will increase the effort that is necessary to obtain an approved PSCP 
April29,2016 Part 23 Reorganization 

FAA-2015-1621 

pageS 

by an order of magnitude. This is not moving in the right direction for most airplane 

certification efforts. 

3. The FAA says on pp. 24 and 52 that switching to consensus standards would not be 

biased in favor of the larger manufactures. We think that the larger manufacturers will 

have the manpower to assign permanent personnel to work on developing standards with 

the ASTM while the smaller manufacturers do not have the resources or manpower to 

assign someone full-time to represent their interests in ASTM standard-writing activities. 

4. The consolidation of consensus standards within the ASTM imposes an economic barrier 

for smaller companies. This move takes the current prescriptive regulations, which are 

presently open and free for any individual to view, and moves them to a hidden "pay for 

access" location. 

An example of similar privatization of standards was the move from MIL-HDBK-5 to 

MMPDS (Metallic Materials Properties Development and Standardization). This 

document is referenced in just about every aircraft structural analysis ever written. MILHDBK-5 was a government issued document, paid for by US tax dollars, with free access 

to all interested parties. When this critical information was transferred to Battelle to 

serve as the custodian, only the first version (MMPDS-0 1) was free. If you want to 

purchase a copy now (at MMPDS-09) you need to pay $679 for an electronic version, or 

$809 for a paper copy. It probably should be just a cost of doing business to buy the 

latest revision every couple of years or so, but a lot of small companies just keep 

referencing MMPDS-01, because it's what they can get. 

This seems to be the direction that this change is going, except with a lot of critical 

documents. It is not very difficult to imagine how this change will save the FAA the 

expense of maintaining documents that are critical pieces of the certification process, but 

it is difficult to see how this change will do anything but increase the costs of certification 

that must be borne by the applicant. 

This new economic barrier also removes transparency from the certification process, 

making it difficult for the smaller company to even know what standards are available 

without purchasing all of them. 

Effectively, these new ASTM standards become rules that must be followed in order to 

show compliance to the proposed Part 23 rules. The FAA has stated that these will not be 

the only accepted means of compliance (just one accepted means), but to achieve FAA 

acceptance of any other means of compliance will require a huge investment of time and 

money- an undue burden for most small companies. (How is this going to save the 

applicant time and money?) It is apparent that for some significant period of time the 

ASTM standards that are in work will be the only rules available that are FAA accepted. 

Therefore, in the interest of transparency regarding the actual certification process (a part 

of which will be veiled behind a pay-per-view barrier), and in the interest of reducing the 

costs associated with achieving certification, we think that the US government should be 

required to make all FAA-accepted consensus standards available to the public, free of 

charge, as is done with Advisory Circulars. 
April29, 2016 Part 23 Reorganization 

FAA-2015-1621 

Are the proposed changes to the rule& supposed to be about reducing the costs of 

certification for the applicant, or only for the FAA? 

page9 

5. It is likely that larger companies with more sophisticated processes, and personnel that 

are dedicated to perform certain functions, will choose to develop their own applicantbased means of compliance. This will enable them to tailor the process of showing 

compliance to the particular needs or approaches developed by their company, or the 

airplane project in question. They will develop their own logic and rationale, based on 

negotiated interpretations of the words in the rules. But when this is done there is no 

incentive for them to work through the ASTM or other publically-accessible holders of 

consensus standards. They won't need the expertise of the ASTM, and why should they 

spend their money to help other companies (including their competitors) have access to 

FAA-accepted means of compliance? They will consider those FAA-accepted means of 

compliance documents to be proprietary intellectual property. 

There is even the possibility that portions of these documents could be patented as a 

process, thereby preventing their competitors from using that process without proper 

licensing, which they would not allow. 

We feel that the cause of airplane certification for smaller companies, or start-up 

companies, will not be advanced under this process. The bar for entry into this industry 

will be raised, making it more difficult to get started. Or, as the existing regulations are 

transferred into an ASTM specification that is FAA-approved as an accepted means of 

compliance, at a minimum the requisite effort will be no less than before. 

6. It appears that if the actual wording ofPart 23 were to never change again, the rules of 

certification would continue to move. Consensus standards would continue to change 

without the benefit of an NPRM to allow applicant review of new versions of standards. 

It is unclear whether the FAA would continue to allow the use of ASTM standard :XXXX 

Revision A when the current released version has advanced to Revision F, but we expect 

that it would not. They would probably say that you could propose it, but how would that 

be different than for today' s process for asking to use an old amendment level for Part 

23? Therefore, the bar would continue to move without recourse for the concerns of 

others that do not have input into the process. 

For example, can the ASTM decide that an earlier version of an FAA-accepted standard 

has a shortcoming and put a clause in the new version saying earlier versions are hereby 

cancelled and are no longer acceptable for new design? Can wording like "this standard 

must be used in its entirety" be written into a consensus standard and it have legal 

meaning? 

Rule Organization 

1. None of the current Part 23 rule numbers remain the same except for §§23.1, 23.1457, 

and 23.1459- all other rule numbers have been changed. Although the present Part 23 

rules will remain available (most of them) as acceptable interpretations of compliance for 

the proposed rules, because the proposed rules are not organized within the existing 

structural outline for content it will not be possible to list the old and the proposed rules 

together in numerical sequence without mixing up the rule topics. 
April29, 2016 Part 23 Reorganization 

FAA-2015-1621 

page 10 

2. Several existing rule numbers have been overwritten by proposed rules that no longer 

contain content pertinent to the existing rule. This will make it extraordinarily complex 

to reference the old rules from a certification basis that is based on the proposed rules. 

This would be especially difficult if 14 CFR §21.1 01 is used to voluntarily certify some 

design change to one of the newly proposed rules without being required to change the 

certification basis regarding compliance to the old rule that had the same number. 

Potentially, a single certification basis could employ two completely different rules that 

have the same number, but at different amendment levels, and both on different subjects. 

Rule numbers that have been "repurposed" for proposed rules of content that is dissimilar 

to the rules that currently inhabit those rule numbers are: §§23.305, 23.405, 23.505, 

23.755, 23.905, 23.925,23.1310,23.1325,23.1335, and all of Appendix A. This also 

applies significantly to §23.1305, which has only partially continued pertinence. Only 

one "repurposed" rule number, although changed, seems to have maintained its original 

content purpose: §23.1505. 

Appendix A to Part 23: This appendix (instructions for continued airworthiness) would 

over-write an existing appendix having a different purpose (simplified design load 

criteria) that was likely necessary for the certification of some earlier airplane. It would 

seem unwise to do this, as it would be confusing to identify rules having identical 

appendix rule numbers only by the era of the document (amendment level). 

We suggest that proposed Appendix A should remain Appendix G. 

3. Please consider calling the proposed rules Part 22, or some other part, to ensure a clear 

distinction between the existing rules to date and the proposed rules. Historically, this 

was done when the CARs became the parts of 14 CFR that we have today, which has 

helped to minimize confusion when referencing these predecessor regulations. We 

believe that the sweeping changes that are proposed deserve their own Part. 

It will soon become extraordinarily confusing to refer to the old and new sections of Part 

23. The existing Part 23 must continue to exist1

, as it is the certification basis for most 

existing airplanes, and (per §21.1 01) will continue to be the certification basis for most 

amended TCs and STCs on those aircraft for many decades. In some ways the old rules 

will become obsolete like earlier amendments of existing Part 23, or the CARs, which are 

inactive rules for new design, but valid for products for which they are the existing 

certification basis. Yet in other ways they all turn into advisory circulars, or publicly 

accessible consensus standards, that are considered one acceptable interpretation of 

compliancel. 

And per the discussion on p.162 (the last sentence in Item 6) regarding 14 CFR §21.101, 

the changed product rule, 

1 Seep. 79, the first paragraph, and the last sentence, "Applicants would need to substantiate the level of safety for 

proposed means of compliance that deviate from the prescriptive regulations." 

2 See p. 110, second paragraph, last sentence: "The FAA expects the current means of compliance would continue 

to be used for the traditional airplane designs under part 23." 
April29,2016 Part 23 Reorganization 

FAA-2015-1621 

page 11 

"This current provision would allow for compliance to the certification requirements at 

amendment 23-62 or earlier when compliance to the latest amendment of part 23 was 

determined by the FAA to be impractical." 

It would seem that almost any existing rule may form a portion of the certification basis 

for new airplanes for a long time to come. 

4. Please consider calling the proposed rules Part 22 (or some other part number) and giving 

the Applicant the option of certifying to Part 22 or the existing Part 23. 

If the adoption of these rules will really reduce the time and cost to achieve certification, 

the industry will choose Part 22 over Part 23. Or, if industry determines that these 

changes do not streamline the certification process, they will reject it and may continue to 

use the existing Part 23. There is significant risk (we feel a high probability) that the 

proposed changes will be determined to be detrimental to the Congress' stated objective, 

and we should not commit to the irreversible dismantling of the world's gold-standard for 

aircraft certification in pursuit of a process that has not been verified to be a success. 

5. What is the FAA's plan concerning existing guidance material that references the Part 23 

regulations by specific number? This affects a large number of Advisory Circulars (e.g. 

21.25-1, 23-16, 23-17, 23-19, etc.) All of these ACs will be out of date when these new 

regulations are issued. 

Rule-specific Comments 

1. 23.1: When there is only one category, and it is called "Normal", what is the point of 

using the term "category"? 

The definition of the term "Empty Weight" could use some clarification. Specifically, 

this weight does not include fuel that may be consumed, but the present wording, "full 

operating fluids, and other fluids required for normal operation of the airplane systems", 

might reasonably be interpreted to include fuel. 

We propose that a definition be provided for the "Minimum Flying Weight" for use with 

a revised wording to §23.300(c)(l). There is no point to certifying that a structure is safe 

for operations below any weight at which it can be operated. The Minimum Flying 

Weight would include the weight of the pilot (or necessary crew) and the minimum fuel 

required for legal operation for the lightest equipped airplane that complies with type 

design requirements. 

2. 23.5(a): Why is there a 19,000-lb upper limit concerning rule applicability? What is the 

basis for establishing this upper limit? Where does the 19,000-lb limit come from or is it 

just an arbitrary number? 

Throughout the preamble the FAA states that they realize that differentiating certification 

by weight categories was inappropriate and did not achieve the desired result. Why then 

arbitrarily attach an upper weight limit to these regulations? This seems to be an 

inconsistent approach when the FAA has worked so hard on this proposal to eliminate 

weight categories. 
April 29, 2016 Part 23 Reorganization 

FAA-2015-1621 

page 12 

We feel that it would be more consistent to differentiate by §23.5 Level and Speed 

categories only. There doesn't seem to be a basis for weight differentiation on the FAA's 

safety continuum. It is imagined that there may be some "turf wars" regarding business 

jets that exceed 19,000 lb, but would otherwise fall well within the 19-passenger limit, 

that are currently regulated within the domain of 14 CFR Part 25. But is there any reason 

that this should remain? It would seem that the applicant should be free to decide if the 

greater rigor of Part 25 would be deemed an asset by their customers that is worthy of the 

extra certification expense. 

Airplanes have always followed propulsion technologies. In particular, airplanes are 

sized by the availability of powerplant choices. There was a time when no one would 

have envisioned that an 800,000-lb airplane could be powered by just two engines, but 

the availability of such engines made those airplanes a reality. Similarly, the prospect of 

a single-engine airplane that exceeds 19,000 lb is not far off. 

So what is to be done with a single-engine airplane that exceeds 19,000 lb, but carries 0 

to 1 passengers? Existing regulations have no home for this type of airplane -not even 

this proposed rule that seems to be questioning most of the arbitrary limits. Again, the 

19,000-lb upper limit seems arbitrary, and technologically limiting. 

This comment also applies to §21.35(b)(2) regarding function and reliability testing. 

Why is there an arbitrary 6,000 lb weight limit to the exemption from this type of testing? 

We would propose that this be resolved by eliminating the need for function and 

reliability testing altogether. The market will sort out function and reliability issues by 

means of natural economic controls -the FAA should have no part in this. 

3. 23.5(c): The insertion of the MMo limits in parentheses is confusing. It is not clear if 

these values represent new absolute constraints, or if they were intended to provide an 

approximate context for what 250 KCAS might mean at some higher altitude. 

As it happens, Mach 0.6 corresponds to 250 KCAS at about 23,400 ft in a standard 

atmosphere, but what performance level would be assigned to an airplane with a 

Vc = 250 kcas and an MMo = 0.65? 

4. 23.10 Accepted Means of Compliance: 

This new rule specifically mentions consensus standards, but then shouldn't this section 

also mention FAA Advisory Circulars as accepted means of compliance? The use of 

Advisory Circulars is almost completely ignored in this NPRM. 

This new rule seems to be mostly procedural, and is unnecessarily constraining. What is 

the intention of requiring by new rule that all means of compliance must be FAA 

accepted? Has there ever been a c"ase where an applicant successfully showed 

compliance (and received type certification) by some means of compliance in which the 

FAA disapproved? There are already FAA Orders which describe the procedural details 

of the FAA certification process and discuss the setting of expectations regarding FAA 

acceptance of certification plans, test plans, and the like. So what failure of the existing 

system led to the creation of this new rule? 
Apri129, 2016 Part 23 Reorganization 

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The existing rules are generally silent on the means of compliance for most rules, but this 

has not prevented airplanes from being certified. Where it has been important to specify 

a particular means of compliance [Ref. §§23.307(b), 23.471 (f), 23.641, 23.683, 

23.723(a), 23.725, etc.] it has been speCified. When a particular means of compliance is 

not specified the applicant has always been free to propose a suitable means of showing 

compliance. So what is gained by writing this down as a new rule? 

It is not clear if the need to obtain FAA approval for each means of showing compliance 

is intended to apply at the beginning of the process (when the certification plan is 

negotiated) or just sometime prior to showing compliance. Draft AC 23.10, Section 5.2, 

seems to suggest that these MOCs will need to be included in the project specific 

certification plan (PSCP). 

What will be the role of DERs, if any, in finding compliance to proposed §23.10? Will 

compliance to this rule always be a retained finding for the FAA? 

In the past PSCPs and Compliance Checklists have been administrative documents that 

were about ensuring understanding between the applicant and the FAA, and for the 

administrative purpose of tracking the project to completion, but were not used to show 

compliance with any rule. It would now seem that FAA approval of an applicant's 

proposed means of compliance- normally contained within the compliance checklistwill become a substantiating document, a document that is used to show compliance with 

§23.10. 

Establishing an acceptable means of showing compliance during the process of 

negotiating the PSCP should be limited to picking one or more of the following: 

Analysis, Tests, Design Review, Physical Inspection, etc. The details of the means of 

compliance for tests may be covered in a test plan that the Administrator will approve, 

but for analytical methods, design reviews, or physical inspections this generally would 

not be true, and would add a new bureaucratic step in the process. 

Any ASTM type of consensus standard used to establish a means of compliance (such as 

the restatement ofthe existing Part 23 rules) would not be sufficiently detailed to function 

as a test plan, so obtaining FAA acceptance of a means of compliance by use of the 

previous prescriptive rules will not take the place of detailed test plans, they will be 

additional non-value-added (relative to the prescriptive rules) documents and approvals. 

It sounds like this rule would require the FAA to review and approve of particular 

methods of analysis (classical vs. finite element, for example) before the analysis can be 

presented. This requirement would be new for most rules, and would require a new level 

of required response from the FAA that would drastically slow the process of either 

establishing the certification plan or showing compliance. 

Oftentimes the details of an airplane design (especially systems) are incomplete at the 

time that application for certification is made. Therefore, it is not always possible for the 

applicant to determine what means of compliance will be employed when the 

certification plan is worked out. At a minimum, it would be necessary for the FAA to 

accept broad, general statements from the applicant when the certification plan is worked 
April 29, 2016 Part 23 Reorganization 

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out, and then move to specific means of compliance as the detailed design is completed 

and the need to show compliance approaches. But obtaining pre-approval is still an extra 

step for most rules. 

In most cases when compliance is shown by analysis a DER is authorized to approve that 

analysis directly, without further involvement by direct FAA personnel. It appears that 

this rule would re-insert the FAA into the approval process by requiring advanced 

approval of the analytical methods that are employed. 

How does this new requirement square with the FAA and Industry Guide to Product 

Certification? Is that document still valid? 

5. 23.215(b), Stall characteristics, stall warning, and spins: 

"Levels 1 and 2 airplanes and level 3 single-engine airplanes, not certified for aerobatics, 

must not have a tendency to inadvertently depart controlled flight." 

There is no explanation in the new regulations about what it means to "not have a 

tendency to inadvertently depart controlled flight", but we can imagine that it will be 

difficult to prove an aircraft meets this requirement! One worrisome thing is the wording 

in Item 2 on p. 9: "The proposed revisions would REQUIRE applicants to use new 

design approaches and technologies to improve airplane stall characteristics and pilot 

situational awareness to prevent such accidents." 

It might seem possible that showing compliance to this regulation could be as simple as 

showing compliance to the current regulations (§§23.201, 23.203, 23.207, and 23.221), 

but per the first sentence ofp. 28 this won't work. We won't know what this means until 

the ASTM specs are issued and approved by the FAA. 

Our company may have problems complying with the intent of this revised regulation. 

Our airplanes are designed to operate and maneuver close to the ground, and sometimes 

close to the stall. Adding some kind of "substantial departure resistance to prevent 

inadvertent stalls from resulting in a departure from controlled flight" (see the first 

paragraph ofp. 70) has the potential to significantly increase pilot fatigue. If the control 

forces are significantly increased as the stalling speed is approached, pilots flying 

agricultural or firefighting airplanes will be forced to work against these barriers 

constantly in an already physically demanding environment, potentially decreasing safety 

by adding to pilot fatigue and reducing maneuverability. 

6. 23.300(a)(1): The establishment ofVA, the design maneuvering speed, should be 

clarified to prevent the possible misinterpretation that this rule defines the purpose of the 

design maneuvering speed, and to ensure that it applies at the design maximum weight. 

We would propose slight rewording, as follows: 

The design maneuvering speed, VA, :whieh may be no less than the airspeed at which the 

airplane will stall at [the maximum design weight and] maximum design maneuvering 

load factor; 
April29, 2016 Part 23 Reorganization 

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The word "which" has been deleted, to avoid misleading the reader to misunderstand that 

the words that follow are the definition ofV A· In most airplanes the design maneuvering 

speed roughly correlates to the stalling speed at the design maneuvering load factor at the 

design maximum weight (VA is defined in §23.335(c)(l) as Vsfn ), but it is not exactly 

that, nor is the purpose of this airspeed intended to protect the overall structure from 

pilot-induced overloads. When the airplane is flown at this airspeed, but at reduced 

weight, it is possible to exceed the design maneuvering load factor without stalling. 

When this is done the flight surfaces may not be overloaded, but the increased load 

factors will increase the loads on structures that support items of fixed mass (such as 

engines, landing gear, cargo, etc.), and these loads may even exceed those that occur at 

critical gust load factors. Therefore it is critical that VA not be viewed as an airspeed 

limit that will prevent inadvertent pilot-induced overloads. 

Under the current regulations the pilot is advised of the need to reduce the speed at which 

abrupt control movements are made at reduced weights via the maximum operating 

maneuvering speed (Vo) established per §23.1507. This speed is reduced as a function of 

the operating weight. 

The true purpose of VA is a design airspeed that limits the structural loads that may be 

applied to the flight control surfaces. IfV A were truly being defined by the wording that 

was proposed it would be at odds with the purpose that it is defmed for all other airplane 

certifications, and with other published discussions about its use. 

It is noted that there is no longer any method for reducing Vc to (0.9)VH. This will be a 

loss for airplanes that are exceptionally draggy (such as agricultural airplanes equipped 

with spray equipment), as they will be required to be designed for loads that are beyond 

what they may experience under normal operations, thereby adding otherwise 

unnecessary structural weight, and reducing the payload that may be carried. 

7. 23.300(b): Our company has had bad experiences3 when the FAA is tasked with 

establishing design maneuvering load factors without regard for the prescriptive formula 

established by §23.337(a). If you have an unusual airplane design situation, there will be 

a protracted battle for any applicant to work out reasonable load factors under the new 

rule. 

8. 23.300(c)(l): The proposed inertia envelope covers weights from "empty weight to 

maximum weight". It is recommended that this range be changed to the "minimum 

flying weight to maximum weight". 

As defined throughout the regulations, the empty weight is applicable to a particular 

aircraft and includes the particular set of options installed when that aircraft is 

manufactured. The term "minimum flying weight" {see comment for §23.1) would be 

more appropriate for aircraft certification because it is not specific to a certain aircraft 

serial number and there would be no confusion between operational and certification 

3 See the discussion regarding Issue Papers at the end of p. 6. 
April 29, 2016 Part 23 Reorganization 

FAA-2015-1621 

page 16 

requirements. See the existing §23.25(b). We believe the actual intent of this regulation 

is to define the minimum possible weight for certification purposes. 

We recommend that you add a definition of the term "minimum flying weight" to the 

proposed §23.1(b). 

9. 23.310(c): For most new airplanes there is no "service history". There is danger here 

that the FAA will require that "service history" be collected before certification is granted 

for a new design. We recommend that the "service history" clause be deleted. 

10. 23.315(a): Are the gust velocities from existing Part 23 or CAR 3 based on measured 

gust statistics? Maybe they are, but we've never seen that technical report. These values 

are quite different between Part 23 (from Arndt 23-7 on) and CAR 3. Would CAR 3 

values be sufficient? Who's to say that the existing Part 23 values will be deemed 

sufficient? 

The freedom that seems to be afforded here to "make up your own requirements" should 

be viewed through the lens of working with a potentially uncooperative FAA counterpart. 

We'd all like to think that won't happen, but most ofus have (on occasion) experienced 

that reality. The FAA also warns at the top of p. 86, 

"Applicants who wish to propose alternate design loading conditions should note that 

extensive data collection, testing, and evaluation may be necessary to substantiate their 

proposaL" 

11. 23.320: Are the "ground handling conditions" from (a) different from the "jacking and 

towing conditions" of (c)? If so, what does it mean? Are we talking about protection 

from "hangar rash"? Do we now need to define the structural loads associated with 

docking an airplane, or from wave motion causing scuffing where a seaplane is moored 

against a dock? 

12. 23.405(d): In the existing regulations [§23.903(b)(1)]. the effects of a rotor burst are 

subject to a minimization rule. That is, there may be some piece of structure whose 

damage from a fragment would be catastrophic, but it is so small and positioned at such a 

distance from the rotor that the probability that a fragment will hit it is so remote that the 

risk is acceptable. It appears that this type of risk is no longer acceptable, and that 

redundant load paths will be required for all principal elements within a rotor burst zone. 

13. 23.41 O(a)(l ): "At all speeds within and sufficiently beyond the structural design 

envelope." What is "sufficiently beyond"? 

The current regulations do not extend beyond the design envelope, although advisory 

material suggests evaluating the response for some distance outside of the approved 

envelope. But this new regulation will require that the structure be approved as free of 

flutter "sufficiently beyond the structural design envelope." Will it now become prudent 

to evaluate the response some distance beyond the point that is determined to be 

"sufficiently beyond the structural design envelope?" 

14. 23.500(b): The requirement that the design data must "adequately defme" the design is a 

welcome addition. This rule will add specificity to the existing rules for type design 
April 29, 2016 Part 23 Reorganization 

FAA-2015-1621 

page 17 

(which presently reside in 14 CFR §21.31) in a location that may be addressed by DERs 

during the review and approval of type design drawings. (Compliance to Part 21 rules 

may not be found by DERs.) 

15. 23. 500( d): We recommend that the FAA revise the wording of this regulation to specify 

that it applies to flight controls. 

It would seem that the definition of"maximum pilot effort" has also been untethered 

from the existing definition afforded in §§23.397(b) or 23.143(c). It will now be 

necessary for every applicant to re-invent the wheel. 

16. 23.515(b): The existing regulation [§23.619(c)] addresses "uncertainties in 

manufacturing processes or inspection methods", as a general or global consideration. 

The new proposed regulation is worded such that the special factor must account for 

"each inspection method", making it specific to the inspection method, whether or not it 

is critical. Inspection methods are generally not defined in an approved type design 

unless they are critical. 

The new wording goes on to include structural test requirements, sampling percentage, 

and process and material controls. Those considerations would be defined in a quality 

system that is approved under a production certificate, but would not be defined in the 

type design. A type certificate is a transferrable commodity (see 14 CFR §21.47), 

whereas a production certificate or an approved quality system are not transferrable (see 

§21.144). Therefore, it is necessary that a type design (which is the object of a type 

certificate) be approved independently of any quality system or production system 

requirements. 

Although most ofthe new rules are worded more generally than the existing rules, this is 

a case where the new proposed rule has added unwarranted specificity. The general 

wording in §23.619(c) is preferable. 

17. 23.600(a): It seems that we should expect future certification efforts to require more 

effort (and possibly full-scale crash testing of the fuselage) to meet these requirements. 

This rule does not specifically say this, but the preamble (Item 1 on p. 8) seems to allude 

to it. 

The "inertial loads likely to occur in an emergency landing" are now undefined, left to a 

yet undetermined consensus standard for definition. It is presumed that the conditions 

defined in the existing §23.561 would be accepted, but doing that won't be any easier or 

faster or less expensive under this new rule. Should some other "inertial loads likely to 

occur in an emergency landing" be proposed the applicant should expect a protracted 

discussion with the FAA to defend any differences. 

Regarding the wording of (a)(l ), we suggest rewording as follows: "Properly using 

safety equipment and features provided ffif in the design." That is, delete the word "for". 

18. 23.600(d): There are an awful lot of requirements in this one requirement. We'd suggest 

that you break it up into parts. 
April29, 2016 Part 23 Reorganization 

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page 18 

19. 23.700(a): This regulation would require safety analysis for all flight control systems in 

order to properly classify any failures as major, hazardous, or catastrophic. Such analysis 

is appropriate for certain kinds of flight controls systems, such as powered or automatic 

flight control systems, but is not appropriate for simple mechanical flight control systems 

(cables, pulleys, chains, etc.). Historically, the precept of structural integrity- or 

structural soundness- has not been subjected to the skepticism of the system safety 

specialists and their probabilistic numerations. This new rule will add cost and 

complexity for the vast majority of new projects, most of which will not be "fly-by-wire", 

Bluetooth-integrated, autonomous flight-capable vehicles. · 

20. 23. 700(b )(3): The wording has changed compared to the current Part 23 rule. Currently 

this only applies to longitudinal controls. The proposed rule would seem to apply to all 

three axes of the flight controls. We do not see how most airplanes will be able to handle 

the failure of a single pushrod on one aileron (which will progressively float upward 

during the landing flair), or how you can land a tailwheel airplane safely without 

directional control. For airplanes without 3-axis trim it may not be possible to certify. 

Or, this rule may drive redundant flight control surface interconnections (ala Ercoupe), 

which may be "safe", but generally undesirable. 

We are not aware that the loss of primary controls due to any single failure in the control 

system (apart from human errors in maintenance) is a significant problem in this industry 

that needs to be fixed. We would recommend a return to the original wording of this 

rule. 

21. 23.700(d): New increased complexity. 

22. 23.810(b): "Airplanes approved only for visual flight rules must achieve lightning 

protection by following FAA accepted design practices." This regulation is extremely 

vague. Its wording doesn't even give an idea of what the level oflightning safety is. It 

offers no real performance standard, nor any means of compliance. Effectively, this 

regulation makes all of those "FAA accepted design practices" (read Advisory Circulars) 

required and regulatory. 

23. 23.900(c): In place of the words "must be type certificated" we would suggest you use 

"must be type certified", or "must possess a type certificate." This comment applies to 

§23.905(a), too. 

The proposed rule is supposed to better support the new wave of modem airplanes, such 

as those with electric motors, or thermonuclear steam engines, or whatever "other power 

sources not yet envisioned"4 may come along. But a type certificate on those 

powerplants will still be required. Is this new rule really going to help those folks? It 

would seem that either Part 33 would need to go through its own drastic changes (and be 

retitled "Aircraft Powerplant Units"), or new regulatory Parts would need to be authored 

to cover each one of these new "powerplant units", when they arrive. 

4 Seep. 123, last paragraph, end of sentence 4. 
April29, 2016 Part 23 Reorganization 

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page 19 

The FAA acknowledges on p. 124 that Part 33 will not apply to those alternative forms of 

powerplant units, and that they will need to obtain an equivalent level of safety (ELOS) 

exemption to this rule in Part 23, and produce a new set of rules equivalent to Part 33 

through the Special Conditions rulemaking process (Issue Papers). Would one of these 

new types of powerplant units receive a type certificate specific to that unit from within 

Part 23, apart from the airplane in which it resides? If Special Conditions to Part 23 were 

used, and the airplane was issued a type certificate that includes the new powerplant unit 

design, but not for the powerplant unit as a stand-alone product, would that powerplant 

unit be considered to carry a type certificate, or merely exempt from the need to have a 

type certificate? Or, would the FAA seek to find a way to issue a type certificate for that 

powerplant unit under Part 33 per the Special Conditions rulemaking process for that 

Part? 

It would seem to be a gross misuse of the Part 23 rules designed to regulate the 

airworthiness of small airplanes - to create a series of rules for the purpose of issuing a 

type certificate for an unconventional powerplant design. It seems that it was intentional 

by the original rule makers to isolate the rules governing the airworthiness of significant 

components of an airplane (airframe, engine, propeller) such that the rules could be 

written to address the specific needs of each type of machine without resorting to overly 

generalized rules (such as, "Airplanes must be safe.") We believe that it would be a 

misuse of the flexibility that is being added to the Part 23 rules to try to apply them to the 

certification of unconventional powerplant units. 

24. 23.91 0: This rule says you cannot have a single~point failure that would preclude 

continued safe flight and landing. This would seem to rule out all single~engine 

airplanes. 

This is about "powerplant system components and accessories", not about the engine 

itself. We're not sure if a fuel line or hose is considered to be a system component, but it 

would seem that the failure of the one fuel line that feeds the engine would certainly 

result in an engine failure. It would seem that there might be similarly insurmountable 

scenarios involving the controls for an engine. 

Now speaking to the potential for conflict with the FAA in negotiating the meanings of 

rules, our company has had to defend the design of single~engine airplanes to FAA 

specialists who insisted that any loss of thrust condition in a single~engine airplane would 

be a catastrophic event. Without clearly written rules, unforeseen interpretations of rules 

like this have the potential to make the design and certification of light airplanes much 

more difficult than they were previously, or even impossible. 

25. 23.920: "The airplane must be capable of continued safe flight and landing under any 

available reversing system setting." 

It seems impossible to expect safe flight and landing with full reverse thrust. It sounds 

like the FAA expects the airplane to "know" the difference between a pilot command for 

reverse when the airplane is on the ground, and one issued when it is still in the air, and 

over~ rule the pilot command if the airplane is still flying. This might seem to be an easy 

control issue when combined with a squat switch, but many airplanes with spring steel 
April29, 2016 Part 23 Reorganization 

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fixed landing gears do not have squat switches. Our company has delivered over 3,000 

airplanes that have spring-steel fixed landing gear, but also have turbine engines with 

reverse thrust capability. Other companies (such as Cessna, Quest Aircraft, and Thrush) 

also manufacture such airplanes. 

We understand that reverse thrust can be a safety issue in some airplanes, but we do not 

believe that it has been a safety issue on these types of single-engine turboprop airplanes, 

all of which employ multiple means to prevent inadvertent selection of the reverse range, 

and warning when that range is selected. This rule will be detrimental to our company 

and our customers, lacking the flexibility that is needed to address the needs of such 

airplane designs. 

26. 23.930(b)(2): We suggest that you add the word "significant" to the phrase, " ... prevent 

[significant] loss of fuel ... " When fuel tanks are full, normal sloshing during taxi or 

takeoff, or when fuel expands as it warms from ground storage temperatures to air 

temperatures, can result in small amounts of fuel being lost via the vent lines. This 

should be permissible. 

27. 23.935(b): The title of this paragraph suggests that it is intended to cover exhaust 

systems, but it reads specifically such that it applies to air induction systems. The way 

that this paragraph reads now is that "the air induction system ... must provide a means to 

discharge potential harmful material." 

This wording appears to mandate the use of an inertial bypass particle separator. We do 

not think this is the intention and suggest making it clear that this applies to exhaust 

systems. If the intent was indeed to mandate an inertial separator, then this paragraph 

does not speak to exhaust systems at all. 

28. 23.1000(t) and (g): We suggest adding the words "if installed" after "fire detection 

system". Otherwise this may be interpreted as a requirement to have a fire detection 

system. 

29. 23.1300(a)(1): This regulation says that we have to meet the required level of safety for 

systems, but it does not define it. On the top of p. 144, the FAA says "as the FAA 

determines which quantitative values satisfied the proposed performance standards, it 

would share that information in FAA guidance". It is unacceptable to tell industry that it 

must meet a level of safety, but the FAA hasn't even decided what that level is. 

30. 23.1300(b): Compare this wording to the existing regulation (§23.1309). This may make 

it easier to certify non-required equipment. However, an FHA and SSA still seem to be 

required. It would be a much bigger improvement if there was a way to relieve the undue 

burden associated with such system safety analysis for non-required equipment and 

systems. 

31. 23.1310(a)(l ): This says that the instruments must show "parameters and trends". Does 

a round gauge instrument produce a trend? We believe it does, but will the FAA use this 

to try to mandate electronic gauges? 
April29,2016 Part 23 Reorganization 

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page 21 

This new rule has repurposed the number from the existing §23.131 0, which currently 

addresses a different subject matter. There is great potential for confusion. 

32. 23.1330(b): It appears that this may be more restrictive than the current §23.1310 in 

regards to single point failures. This may require that there be no single failure points 

between the power supply and the essential load bus. 

33. 23.1335(d): "The applicant must design and install taxi and landing lights so they 

provide sufficient light for night operations." We don't see where the regulations require 

night operations so we think "if installed" should be added after "taxi and landing lights". 

34.23.1400: "Safety and survival equipment, required bytheoperatingrules ofthis chapter, 

must be reliable ... " This may require some kind of testing or certification of fire 

extinguishers, etc. Would the current UL rating of the fire extinguishers be enough? 

35. 23.1500(b): This regulation seems to add a lot of extra requirements to monitor and 

perform ALL tasks associated with [ALL] systems and equipment. Surely this was not 

the FAA's intention. We would suggest that you change this to say " ... perform all 

[required] tasks associated with the intended functions of systems and equipment." 

Now regarding the second sentence, 

"The system and equipment design must make the possibility that a flightcrew error 

could result in a catastrophic event highly unlikely." 

Unlike a random failure, one cannot put a probability on the likelihood of a human error. 

Therefore, any error that anyone can think of will be fair game. Additionally, the term 

"highly unlikely" is so vague that it could easily be interpreted to mean "that error won't 

happen". But there is a never-ending list of ways that a crewmember error could (not 

would) result in a catastrophic event. What if he forgets to tum on a needed system at 

just the wrong time? (The system must not allow it.) What if he inputs the wrong setting 

at just the wrong time? (The system must not allow it.) What if he goes too fast, goes 

too slow, banks too much, descends too far, or grabs the wrong control? (The system 

must not allow it.) Things that would usually be a minor mistake during most 

circumstances could result in a crash under the most adverse conditions (such as during 

single-pilot, night, IMC, turbulence, and when tired after a long day). Anyone who 

thinks that the FAA won't raise these kinds of scenarios is kidding themselves, because 

they already do. 

If the wording of this rule is not changed the complexity of systems in Part 23 airplanes 

just increased exponentially for this rule. 

36. Appendix A to Part 23: This appendix would over-write an existing appendix (simplified 

design load criteria), having a different purpose, that was likely necessary for the 

certification of some earlier airplane. All of the other appendices are deleted now. It 

would seem that there will be a lot of new airplane projects that reference inactive rules 

for showing compliance to the new vague rules. Or, there will be a lot of wheelreinventing going on ... 
April 29, 2016 Part 23 Reorganization 

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37. 91.323(b)(3): In the special rules that are applicable only to operators of airplanes in the 

State of Alaska, the automatic increase in approved maximum weight has been changed 

to reflect a maneuvering load factor that is now independent of the load factor defined in 

Part 23, but matches the previous §23.337 definition. 

Now there is increased likelihood that the load factor considered under this new rule will 

not match the load factors that were used in the original certification of the design, 

because it is possible that some consensus standard will impose some other creative 

interpretation. Hypothetically, if the applicant and the FAA decided that some new 

airplane design needed to have a design maneuvering load factor of 4.5g to be safe, this 

regulation would happily give the operator the authority to operate it at a weight no less 

than 136% of the weight for which the manufacturer designed and tested the airplane, and 

possibly even more. 

It seems that safety would be better preserved if the special Alaska rule was required to 

reference the load factors that were used in the original certification, whatever those 

might be. But of course, the public will not know that information under the proposed 

rules, which will be shrouded in the secrecy of whatever private negotiations for 

acceptable means of compliance occurred during the original certification. 

This whole automatic gross weight increase thing has always been incongruent with 

reasonable concerns for safety, which we believe is part of the FAA's mission. What is 

the purpose of requiring manufacturers to do fatigue testing on airplanes that will be 

operated in Alaska? 

As a manufacturer of restricted category agricultural airplanes we understand the desire 

to make the most of the structural strength of an airplane design. In our industry the rules 

of CAM 8 have been used for a purpose that is in some ways similar to the results of 

§91.323 for Alaskan operators, but CAM 8 also imposes restrictions on the maximum 

maneuvering load factor, or the limiting design airspeeds, to compensate for overweight 

operations. Additionally, our airplanes are certified for fatigue with consideration to the 

weights at which they are actually operated. §91.923 seems to provide no cOmpensating 

factors for its permitted operation at weights beyond its certified maximum weight. 

In closing, 

1. These changes are drastic, sweeping, and it is not at all clear that they will produce the 

positive effects that are desired. It would seem to be imprudent to make such changes 

without significant assurances of success, or provide for the continued use of the existing 

rules in the event that the effect is not beneficial. 

2. It does not appear that any significant rules have been discarded, only that those 

requirements have been consolidated into fewer general or vaguely worded rules, for 

which acceptable means of compliance have not yet been established. 

3. It has been our consistent experience that vaguely worded rules lead to more difficult and 

time-consuming discussions with the FAA, and delayed decisions, not expedited 

acceptance. 
April29, 2016 Part 23 Reorganization 

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page 23 

4. It has been our consistent experience that FAA acceptance of past applicant-based means 

of compliance does not guarantee continued acceptance today, or in the future. 

5. The use of consensus standards may bring flexibility to these rules that will help them 

accommodate non-standard airplane designs, but it is doubtful that the process for 

developing such standards will be any more agile or less cumbersome than the existing 

issue paper system. In fact, it is not clear that the FAA will use anything other than the 

issue paper process to determine the acceptability of new consensus standards. 

6. The use of consensus standards for most "normal" airplanes will greatly retard the 

process of developing an approved certification plan. The most expeditious path to 

achieving an approved certification plan will be to adopt the means and rule 

interpretations from the current Part 23 rules (if permitted), except that each adoption will 

now require a discussion (and new critical review) before each is accepted by the 

Administrator. It is unclear how this repackaging of the requirements will be able to save 

the Applicant any time or money in achieving type certification. 

7. The use of consensus standards that are developed independently of any previously 

approved rules will be as time-consuming and expensive as any other option. This is 

because the FAA will place the burden of proof that the means are appropriate on the 

Applicant, and such standards will require time for critical review and input by industry 

peers and other experts in the field prior to presentation to the FAA for acceptance. 

8. The use of applicant-proposed means of compliance standards will inevitably lead to 

significant differences in the standards that are imposed on different applicants for use on 

similar products. Such disparity in accepted means of compliance will naturally occur 

with greater variance as different individuals within the FAA interpret these intentionally 

more flexible (but also more vaguely defined) regulations. 

9. The use of applicant-proposed means of compliance standards will lead to a significant 

loss in the transparency of the certification process as individual applicants may choose 

to make both the results and the process of showing compliance to any particular rule a 

matter of proprietary intellectual property, with advantages for maintaining the 

confidentiality of such processes. 

1 0. The costs associated with the use of consensus standards that are housed and maintained 

by the ASTM (or some similar group) will deter small companies from accessing and 

using them. It seems that it will not be possible to "shop" for the right standards, or study 

them for possible implementation, without first purchasing them. It is likely that a lot of 

standards will be purchased that will not get used, and that the best standards that are 

available will sometimes not be used because they were overlooked or undiscovered due 

to the costs associated with their discovery. 

11. The numerical organization of the new rules, being interleaved with the existing Part 23 

rules, will be problematic. The "decoder ring" that will be issued to line up old rules with 

new rules, for use with hundreds or thousands of Advisory Circulars, Policy Statements, 

Orders, and the like, will soon be unacceptably confusing. 
April29, 2016 Part 23 Reorganization 

FAA-2015-1621 

page 24 

12. Several rules and all of Appendix A -have been overwritten with dissimilar content, 

repurposing existing rule numbers. This will lead to confusion. 

While we appreciate the intent of these proposed changes, we strongly believe that these rules, if 

adopted, will not have the desired effect on safety, or reduce the costs or time necessary to 

achieve FAA certification. In particular, these proposed rules ... 

1. Will reduce the certainty that is needed to adequately plan for the design and certification 

of a new airplane; and 

2. Will increase the number and duration of the interfacing events that the applicant must 

have with the FAA. 

In our opinion, the purposes of reducing the costs and time necessary to achieve FAA 

certification would be better served by a process that accomplishes the following: 

1. Increase the certainty needed to adequately plan for the design and certification of a 

new airplane. 

Retention of the current prescriptive rules are the best way to do this for most airplane 

designs. For those airplanes of non-standard design the issue paper process is already in 

place, and would provide the equivalent of applicant-proposed means of compliance that 

this proposal is championing. 

2. Reduce the number and duration of the interfacing events that the applicant must 

have with the FAA. 

In general, time is spent debating requirements, means of compliance, waiting for FAA 

reviews and approvals oftest plans and analysis that the FAA's experts (DERs) have 

already reviewed and for which they have recommended approval, and procedural steps 

regarding conformity inspections. The certification process would be the most 

dramatically improved if the FAA would delegate approvals for all substantiation 

documents to its DERs, including test plans, safety analysis, and flight testing, such that 

the FAA would only be involved at the beginning to set the certification basis and 

approve the certification plan, during the process to assist and advise the DERs and the 

Applicant, and at the end to award the type certificate. 

Sincerely, ~ ~ 

cc~ Certification Manager, Air Tractor Inc.