To: Nick Lappos and Grey Area
Nick Sez:
“Regarding Lu, he simply cannot learn, and he is reading a design FAR paragraph as if it were a test paragraph. He is foolishly unable to listen - it simply proves yet again how his stubbornness degrades the value he could add. I am sorry that I have caused all of us to scroll down past his drippings, where he thinks he has to re-post his entire last post again and again and again”.
Lu Responds:
In the CFR 14 document under Subpart A-General Paragraph 27.1 Applicability subparagraph (a) it states the following. This part prescribes airworthiness standards for the issue of type certificates, and changes to those certificates. For normal category rotorcraft with maximum weights of 6,000 pounds or less.
Paragraph (b) states: Each person who applies under part 21 for such a certificate or change must show compliance with applicable requirements of this part.
Lu Responds Further:
In the CFR 14 document under Subpart B-Flight, Paragraph 27.21 it states the following: Each requirement of this subpart must be met at each appropriate combination of weight and center of gravity within the range of loading conditions for which certification is requested. (My words) It implies that this can be done by flying the aircraft under the stated conditions of the sub paragraphs or by calculations based on, and equal in accuracy to the results of testing. With the advent of super computers Nick may be correct in stating that no (flight) test is required. That may be true at Sikorsky but not at Robinson and that is the topic we are addressing.
Grey Area may also be correct in stating that the advisory circular is just that as it is the compendium of experience gained over the last 25-30 years in the certification of Normal Category Rotorcraft as that is stated under paragraph (a) under Purpose. However under paragraph (5) Applicability it states the following: This material is not to be construed as having any legal status and must be treated accordingly. However, to ensure standardization in the certification process, these procedures should be considered during all rotorcraft type certification and supplemental type certification activities. (My words) However just about everything contained in AC-27 is contained in CFR-14 part 27 so the requirements of the testing must be complied with to include the test for out of trim and 90-degree sideslip. This means that at Robinson they had to demonstrate this capability in actual flight and not in a super computer which they did not possess at that time.