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Tales from the DAR Side

Operating Limitations Aerobatics

Joe Norris
Joe Norris

We’ve already covered a lot of details about amateur-built aircraft operating limitations, but we’re not quite done with the subject yet. Last month we discussed major changes. One place where you might need to invoke the major change procedure is when adding aerobatic maneuvers to the aircraft’s operational envelope.

The first thing one needs to do is to make sure the aircraft is capable of aerobatic maneuvers. Sure, it’s an experimental aircraft, and performing aerobatics might be part of the experiment. But it’s important to know whether the designer had aerobatics in mind when designing the aircraft in the first place. Some designs might not be at all appropriate for aerobatics, either from a performance or a load-bearing standpoint (or both). Make sure you’re operating within the design parameters of the aircraft before performing aerobatics.

Assuming that the design is capable of aerobatic loads, the next thing you need to check is whether the FAA has allowed aerobatics in the aircraft’s operating limitations. The operating limitations will include one or the other of the following items:

This aircraft may conduct aerobatic flight in accordance with the provisions of § 91.303. Aerobatics must not be attempted until sufficient flight experience has been gained to establish that the aircraft is satisfactorily controllable and in compliance with § 91.319(b). The aircraft may only conduct those aerobatic flight maneuvers that have been satisfactorily accomplished during flight testing and recorded in the aircraft logbook and maintenance records by use of the following, or a similarly worded, statement: “I certify that the following aerobatic maneuvers have been test flown and that the aircraft is controllable throughout the maneuvers’ normal range of speeds, and is safe for operation. The flight-tested aerobatic maneuvers are _________, _________, __________, and __________.”

or,

This aircraft is prohibited from aerobatic flight, that is, an intentional maneuver involving an abrupt change in the aircraft’s attitude, an abnormal attitude, or abnormal acceleration not necessary for normal flight.

This verbiage comes from the current version of operating limitations. Earlier versions may contain slightly different language, but the intent will be the same. Obviously you need to have the first item if you want to perform aerobatics.

It’s very important that you not assume the aircraft has the appropriate limitation. There have been cases where aircraft that are obviously capable of aerobatics don’t have the appropriate limitation. One time, I worked with an EAA member who had just purchased a flying Pitts Special. In reviewing the operating limitations he found that the FAA had issued the limitation prohibiting aerobatics! Needless to say, he got the limitations changed pronto!

So you got an aerobatic design with the appropriate operating limitations. What’s next? Testing the maneuvers! The FAA says that no experimental aircraft can perform an operation or maneuver during Phase 2 (normal operations) unless that maneuver or operation has been tested during a Phase 1 flight-test period. So even though the aircraft is capable of aerobatics and authorized by operating limitations to do so, you can’t legally perform any maneuvers except those that have been tested during a flight-test period and appropriately recorded in the aircraft records. If there’s no record that an aerobatic maneuver has been tested, you can’t legally perform it.

There are two ways to go about testing and logging aerobatic maneuvers. First, you can test the maneuvers during the initial flight testing of the aircraft, or you can add maneuvers through the major change process. In the former situation, you’d want to wait until late in the initial flight-test period after the aircraft has proven itself in all normal operations. In the latter situation, you’d need to follow the major change procedure as we discussed in last month’s column.

Either way, you must make the appropriate entry in the aircraft records logging what maneuvers were tested. I would recommend that you record the maneuvers in some detail, including things like entry speeds and any details specific to the aircraft (fuel system configuration, etc.) In the case of adding maneuvers through the major change process, you need to make two entries in the aircraft records – one closing out the major change flight-test period and another recording the maneuvers tested; the verbiage for these entries is in the aircraft’s operating limitations. But it would be acceptable to make a single entry combining the language of both.

So there you have the “ups and downs” of operating limitations as they apply to aerobatics. We’ll continue our discussion of operating limitations next month!

 

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