MOC VTOL.2235 Structural
strength
n/a
|
Note: At this issue, this MOC
addresses landing gear drop test requirements only. Additional MOC will be
added in future issues to address, for example, allowable damages to the
aircraft for the Category Basic controlled emergency landing. |
(a)Â Â Â Â Shock absorption tests: CS 27.723 Amdt. 6 is accepted as a means of compliance.
(b)Â Â Â Â Limit drop test: CS 27.725 Amdt. 6 is accepted as a means of compliance.
(c)Â Â Â Â Â Reserve energy absorption drop test: CS 27.727 Amdt. 6 is accepted as a means of compliance. In addition:
(1)    Shock absorbing devices, such as oleos, should not “bottom” during the reserve energy drop test. “Bottoming” occurs when displacement of the device no longer occurs with increasing load. (for further guidance see FAA AC 27.727(a)(3) in FAA AC 27-1B Change 7, which is the EASA AMC as per Book 2 of CS-27 Amdt. 6)
Notes:
(1)Â Â Â Â The proper attitude for the aircraft after the reserve energy absorption drop test is an attitude which allows for permanent deformation of landing gear elements but provides for adequate egress from the aircraft (for further guidance see FAA AC 27.727A (b)(1) in FAA AC 27-1B Change 7, which is the EASA AMC as per Book 2 of CS-27 Amdt. 6).
(2)    External accessories that may not impact the landing surface during drop testing include devices such as externally mounted fuel tanks or accessories that are likely to cause post-landing fires. Cameras, loudspeakers, and search lights may be damaged during deformations resulting from reserve energy drop tests if electrical connections are sufficiently protected to preclude electrical fires and the devices are not likely to penetrate fuel tanks and other energy sources. The expendable accessories, if installed, should also be designed to not have “hard points” that would unacceptably damage the aircraft structure under landing impacts by penetration into the occupied areas or fuel tanks. These expendable accessories should be designed with frangible fittings, frangible devices, or comparable design features. Also, these devices should be designed to not significantly alter the energy absorbing ability or design features of the landing gear (for further guidance see FAA AC 27.727A (b)(2) in FAA AC 27-1B Change 7, which is the EASA AMC as per Book 2 of CS-27 Amdt. 6).
(3)    External accessories may not contact a level landing surface after “limit landing load” deflection of the landing gear, i.e. the deflection resulting from the limit drop test described in paragraph A of this MOC.
EASA VTOL aircraft landing gear must pass shock absorption, limit, and reserve energy drop tests. Shock absorbing devices shouldn't bottom out during testing. Post-test aircraft attitude must allow safe exit. External accessories must not cause fires or structural damage upon impact and should not alter landing gear performance.
* Summary by Aviation.Bot - Always consult the original document for the most accurate information.
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