Sent: Friday, August 08, 2008 7:07 PM
Cc: 'AntiqueAirfield@sirisonline.com'; Robert Lock; 'firstname.lastname@example.org'; 'email@example.com'; firstname.lastname@example.org
Subject: AC 23-27, Parts and Materials
Dear Mr. James,
I am submitting the following commentary on the Draft Advisory Circular # 23-27 titled, “Parts and Materials Substitution for Vintage Airplanes”.
First, I would like to state my interest in this from three vantage points and provide some general observations.
1. As the Chief Engineer and DAS administrator for RAM Aircraft LP, I have an expressed interest. I am directly involved in certifications of aircraft falling under the “Vintage” category as it is defined in the Draft Advisory Circular. Our company has been in the business of modifying and maintaining these airplanes since 1976. In fact, we are experiencing some of the exact same issues within our own STC products that were certified early in our history and subsequently some of our approved parts have since become obsolete to current technology. In our case, we have an engineering staff and a network of consultants on our DAS to help us with appropriate part substitution approvals. So we have resources at our disposal that the flying public is without. Guidance such as this AC is much needed in the industry to help inspectors, mechanics, DERs, DARs, Repair Stations, and owners. We applaud the FAA and other organizations such as the AOPA, EAA, and type clubs for their efforts that have brought this proposed AC to the forefront.
2. As a consultant DER, I have a vested interest and concern for the type design configuration of the “Vintage” airplanes which I am frequently involved with for consideration of approval. This Draft AC, if properly infused, has the potential for greatly simplifying and lightening the burden of certification to FAA engineers, FAA inspectors, and owners/operators by allowing more flexibility in the configuration control aspects of maintaining type design. A general comment is that the AC as drafted does little toward simplification. It is missing some current FAA policy such as “Owner produced parts” (OPP) that would allow greater flexibility. The AC emphasizes PMA, STC, and Repair Station methods of certification. And it does not mention much about other (more-simplified) approaches such as “owner-produced-parts”, field-approval or return-to-service via 337 with DER approved data. These processes are valid, and acceptable approval means and are much less expensive to the operator.
a. My observation is that this AC seems to offer only the approval processes of Aircraft Certification Service (AIR) branch of the FAA, but has little to offer along the lines of the more simplified certification processes through the Flight Standards (AFS) branch of FAA. One of the most frustrating aspects facing DERs and aircraft operators today is the increasingly cumbersome myriad of changes that go back and forth between AFS and AIR. There seems to be little coordination between AFS or AIR when implementing policy, guidance, or even rulemaking and orders. The AFS and the AIR groups within the FAA should work more closely together than they have been in recent years. One case in point is the recent release of FAA Order 8300.14 which creates a new RS-DER category for approving major repairs. Most of us DERs, when asking our ACO counterparts about this, find that the FAA ACO has little or no knowledge of the criteria or qualification requirements to issue such delegation. Apparently AFS has created something without consulting the AIR group. This debacle has caused much confusion concerning repair documentation among general aviation because it seems that the left hand of FAA does not know the activities of its right hand. With that said, it is refreshing to see an effort such as this Draft AC toward simplification. Please ensure “simplification” to be the focus of the AC, otherwise the guidance will be of no added value. And also please consider a thorough process of coordination between AIR and AFS before this guidance is released.
b. It has been my experience that any approvals that involve ACO processes are much more expensive to the operator than those supported by the FSDO. Small aircraft owners call me frequently after having been advised by ACO or FSDO that they are facing an STC approval and should contact a DER. They are appalled when I return an estimate for STC vs. field approval support. I usually spend more than 10 times as many hours preparing documentation for STC support vs. Field Approval support. Many of those hours are spent in helping the ACO engineers in becoming familiar with the product. For most owners of vintage airplanes, this is cost prohibitive. This holds true for PMA approval vs. owner-produced parts or some other accepted means. Although, my fee is that much greater, that does not mean that the regulatory requirements are any different. My approval (whether supporting an STC or Field Approval) is the same. It is issued only after a full demonstration of compliance to the applicable requirements of Title 14 of the Code of Federal Regulations (14 CFR). The difference is in the time I spend writing reports and documentation in a way that unfamiliar FAA engineers can understand enough to satisfy the complex FAA certification processes. The operators of small GA airplanes view this as restrictive and bureaucratic Government control.
3. As the Owner/Operator of three vintage airplanes myself (one which was built in 1929 and has an orphaned type certificate), I have a vested interest and concern for the costs and frustrations of maintaining my airplanes. This AC for the reasons mentioned above, has the potential for allowing me to make technological improvements to my aircraft without facing cost prohibitive certification processes. I am faced with the decision of whether to spend thousands of dollars to implement an improved set of brakes, or new exhaust, or an alternator, or more reliable spark plugs, etc.; or to continue operating with worn and obsolete parts because it is all I can afford to do. The thousands of dollars is no stretch when the STC and PMA process is involved. And the fees are more associated with following the FAA processes themselves and are not directly associated with finding the parts to be in compliance with applicable regulations and appropriate for installation. It is more associated with the cost of paying a DER to develop test plan documents and other certification reports, and a DAR to take my airworthiness status into and out of experimental, and a te$t pilot to fly my airplane which I am more experienced and qualified to fly. I am left with no viable option but to settle for compromised safety. So again, I am hopeful that the proposed AC can relieve some of this for me and others like me.
One alternative for the owner-operator that I think industry and FAA are both missing out on is the ‘owner-produced-part’ (OPP) policy. Please expand this AC to clarify the the FAA policies on owner produced parts. Appropriately rated DERs can be involved in development and approval of design data for parts as major alterations. If this were more widely communicated through FAA guidance, many of the operator issues would be solved. Take my Dad’s 1929 Curtiss Robin for example. With evaluation from an appropriately rated DER, the springs for the oleo strut landing gear can be produced under the OPP policy. To do this, the DER would evaluate the aircraft for it’s weight, ground ops, landing loads, and other regulatory requirements. He can then specify the spring design details in a drawing with 8110-3 approval for a major alteration. Current FAA policy would allow my Dad as the owner of the aircraft to supply this approved drawing to the supplier, have the part made with his oversight, inspect the finished part to verify conformity to the approved drawing, then submit a 337 with 8110-3 attachment. A similar alternative would be to have DER support to reverse-engineer parts using appropriate means such as matching the original materials through metallurgical lab analysis. I believe that a very few FAA inspectors and engineers are aware of how much these kinds of approval options are needed and are already acceptable under FAA policy. They can help the vintage airplane problem by supporting DERs and owners in this effort. This in my opinion would be the greatest leap forward in helping to solve the whole vintage aircraft parts supply issue.
Secondly, I have the following specific suggestions for the AC verbiage that I believe would add significant value and are within the current FAA policy, orders, and regulations.
Sec. 3.b Please add, “This data is equally applicable for a DER to use as substantiating data in (1) for a one-only major alteration by establishing the aircraft eligible for a previously approved PMA part; (2) for determining compatibility between two separately approved prior modifications; (3) support of a major repair or alteration under 337 (being executed with DER approved data); or (3) for use as substantiating data in support of a PMA or Supplemental Type Certificate (STC) project.”
Sec. 5.a Please add, “Examples of ‘other sources’ are PMA parts that are eligibility-wise approved on other similar aircraft, Owner-produced parts, Military Surplus parts, Used Serviceable parts that are from a similar model aircraft of the same make.”
Sec. 5.b Please add, “ Appropriately authorized DER’s can assist in developing the data and provide FAA approval for such alternate materials and designs, which may be produced under the FAA accepted policy for ‘Owner-Produced Parts’.”
Sec. 5.c Please add, “Appropriately authorized DER’s can assist in making these kinds of determinations and findings of compliance within their specialized field.”
Sec. 5.d Please add, “...such as field approval, owner produced parts, 337 major alteration or major repair with DER support.”
Sec. 5.f Please add, “Appropriately authorized DERs have the necessary knowledge, skill, experience, interest, and impartial judgement to merit the responsibility of making these determinations and making findings of compliance with the applicable airworthiness regulations.”
Sec. 7.b.1 Please add other predecessor regulatory certification basis such as CAR 4, CAR 4a, CAR 8, etc. as many of the airplanes that are intended for this AC have certification basis other than Part 23 or CAR 3. Also I suggest expanding the scope of the AC to include engines as well. Perhaps this becomes too broad in scope, but I think operators need the same relief in this area. Please consider adding Part 33 and CAR 13 to this section.
Sec. 7.c.1-4 Suggest adding clarification of who is referenced as “you”.
Sec. 7.c.4 Please add, “...or develop any missing data through support from an appropriately authorized DER or ACO approval.”
Sec. 8 Please add FAA definitions from policy concerning “owner produced parts”.
Sec. 12.c I believe there is a typo here. I could not locate section 19. Also... please do not leave out the FAA policy for accepting parts manufactured by a repair station by duplicating the original part using same materials, etc...
Appendices 1 & 2: Suggest adding clarification of who is referenced as “you”.
A final comment on the recent EAA proposal for “vintage” DER’s... If the FAA is considering such, please recognize that authorizing them by ”type” of aircraft would offer little help because there are so many unique one-off designs. The “vintage” title is worthwhile for consideration. But I believe it should be an authorization to DERs with experience and qualifications in recognizing which engineering disciplines must review the data (much like an administrative DER or management DER). I have not been completely educated about their proposal, but I believe the EAA is trying to say that certain people are more familiar and experienced with these old airplanes than the FAA is. This is 100% true. I believe it is time for the FAA to recognize qualified individuals and authorize them for such.
I applaud the efforts to make this guidance material available and am happy to spend my time in offering my suggestions. And I repeat... Please ensure “simplification” to be the focus of the AC, otherwise the guidance will be of no added value. I encourage you to contact me for further discussion or clarification if you so desire.
Regards,Terry L. Bowden,
DAS administrator / Chief Engineer - RAM Aircraft Limited Partnership
Consultant D.E.R. Powerplant & Engines; A&P Mechanic; Private Pilot
Owner: 1946 Taylorcraft BC12-D
Operator: 1939 Taylorcraft BC-65, 1929 Curtiss Robin C-1, 1956 Champion 7EC