FAA disposition of comments to FAA AD 2012

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Commenter 1 made three comments: Comment 1: Comment on the FAA's Determination of an unsafe condition: “ The start of the roll oscillation in LOC mode at the end of an approach does not lead to an unsafe condition. ” FAA Disposition: The FAA made the determination that the autopilot behavior in the single

- pilot IFR operations environment is a safet y issue and rose the level of an unsafe condition based on flight evaluations involving both certification t est pilots and a flight standards aircraft evaluation group operations pilot
. Follow up analysis using the FAA monitor safety and anal yz e data process, showed that the autopilot behavior rose the level of an unsafe condition. Comment 2: Comment on AD requirements:

“ Alternate way s to safel y complete an approach below 500 ft than using the LOC mode in 4

- axis configuration have been extensively demonstrated in single pilot IFR operation. Eurocopter agrees to increase the LOC mode Minimum Use Height, in 4

- ax is configuration, from 200 ft to 500 ft over the US territory but disagrees with the EC155 interdiction of single pilot for IFR operations. ” FAA certification requires the autopilot to perform its intended function throughout its operational envelope. Fo r single pilot operations, particularl y in commercial operations (14 CFR 135), an autopilot can be used in lieu of second

- in

- command for IFR operations. The autopilot in this case did not provide a stabilized approach on the final approach segment. Incre asing the minimum use height (MUH) from 200 ft to 500 ft would not alleviate the requirement of the autopilot to be “. . . capable of operating the aircraft controls to maintain flight and maneuver it about the three axes; . . .”(14 CFR 135.105 (c)(1)). Changing the MUH to 500 ft would not solve the issue but only restrict single pilot IFR to Part 91 operations. The FAA considered limiting the dual pilot IFR requirement to 14 CFR 135 operations only but that solution was not considered feasible since the behavior of the autopilot was not performing its intended function and was considered presenting an unsafe condition regardless of whether the aircraft was operating under general aviation rules (Part 91) or commercial operations (Part 135). Comment 3: Comment on costs of compliance: “ The FAA AD strongl y underestimates the Costs of Compliance because it does not take into account the additional operator cost due to the 2nd pilot in IFR flight. ”The FAA only considers the direct cost for the actions man dated, ie parts and man

- hours to perform inspection/replacement in accordance with FAA

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- 8040.1C, paragraph 9.e. which states: “Do not state an y costs beyond initial work

- hours and parts costs; that is, don’t include costs that operators might incur in individual maintenance scheduling or costs that operators might pass on to others.” When the FAA was determining the cost of the AD to operators, the decision not to include the cost of adding a second pilot was considered and rejected. The investigat ion into the fleet of aircraft impacted b y a dual

- pilot IFR limitation revealed that there were six EC155B1 aircraft in the U. S. fleet. Three aircraft had, at the time the investigation was accomplished, not been delivered to their operator. Two of the aircraft were operated b y commercial operators who did not have single

- pilot IFR operational approval for operations under 14 CFR 135, and one aircraft operated b y the aircraft manufacturer ’ s U.S. facility

as a marketing demonstrator. Therefore, the econo mic impact for commercial operations at that time was negligible for the existing U.S. fleet. Additionally , the FAA did not include the cost of a second pilot since operators are not required to fl y their aircraft IFR.
The second commenter provided fi ve comments to the AD. The format of the comments do not support inclusion verbatim in this response so they are paraphrased. Comment 1 : The commenter stated they did not believe pilots would find themselves in “loss of control” situation given the beh avior of the autopilot. The commenter also stated that they had no indication from other world

- wide EC155B operators that the oscillations they experienced created concerns about additional workload or loss of control. The autopilot oscillations and the point on the final approach segment where they occurred, did not provide a stable approach platform. The FAA made the determination that the autopilot behavior in the single

- pilot IFR operations environment is a safet y issue and rose the level of an unsafe condition. This determination was based on flight evaluations involving both certification test pilots and a flight standards aircraft evaluation group operations pilot. Follow up analy sis using the FAA monitor safet y and anal yz e data process, showed th at the autopilot behavior rose the level of an unsafe condition. The FAA was unaware that the there were other pilots in other countries experiencing the same issues. Comment 2: The commenter stated that if the FAA conclusion that an unsafe condition exists, the most stringent restriction should have been two pilots for ILS/LOC approaches planned to be flown in IMC and allow other approaches such as GPS, VOR, ADF approaches to be flown single pilot.The FAA considered various iterations of limitations to mitigate the issue. The end result

was that the FAA decided to issue the dual

- pilot IFR limitation instead of operationall y specific limitations because the dual pilot limitation did not limit where the aircraft could fly I FR vs. other limitations that limited where the aircraft could fly . Additionally , the FAA determined that the AD does not require operators to fly I FR and the decision to do so is their choice. Comment 3: The commenter stated they had raised this issue a number of years ago. The FAA considers this a statement of fact
. Comment 4: The commenter raises the issue that the FAA underestimated the cost of implementing the AD because of the cost of installing a cockpit voice recorder required under 14 CFR 135. The FAA’s investigation revealed that there were no 14 CFR 135 operators flying EC155B1’s who had authorization to fly I FR or fly

I FR using the autopilot in lieu of second in command. As a result, this cost was not considered since it did not apply to the current U.S. fleet. C omment 5: The commenter stated that it was OK to fly single pilot IFR for the number of years since they

brought the oscillation to the FAA and manufacturer’s attention but now immediate action is required. Research into the oscillation issue revealed on e service difficult y report on the EC155B autopilot sy stem entered in 2005. There was no other previous documentation on the FAA’s part that this issue was reported through the FAA’s service difficulty reporting sy stem.