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Means of compliance: Operations over people

drone hitting test dummy

The Means of Compliance we developed in partnership with the Virginia Tech Center for Injury Biomechanics is intended to evaluate the potential injury severity from a small uncrewed aircraft (sUA) according to the Operations Over People rule for Category 2 and Category 3 operations (see below for more on these categories). Specifically, the MOC is used to show that the sUA does not

  • exceed the applicable comparative injury severity limits upon impact with a human being.
  • contain any exposed rotating parts that would lacerate human skin.

The injury severity data collected with this MOC must be combined with an FAA-accepted Declaration of Compliance (DOC) to allow operations over people.

Category Definitions

Injury severity less than that caused by transfer of 11 ft-lbs of kinetic energy from a rigid object.

No exposed rotating parts that could lacerate human skin.

Minimal operating restrictions - must have Remote ID for flight over open-air assemblies.

Requires an MOC and DOC.

Injury severity less than that caused by transfer of 25 ft-lbs of kinetic energy from a rigid object.

No exposed rotating parts that could lacerate human skin.

May not operate over open-air assemblies; may operate over human beings only if access to the site is restricted or flight is never sustained over nonparticipants. 

Requires an FAA-accepted MOC and DOC.

Evaluation Process

OEM provides data on UAS.

Test site conducts design review to identify likely failure modes and potential safety defects. 

In the absence of sufficient OEM failure data, supplemental testing may be performed to characterize failure modes. (A common example of failure mode testing is wind tunnel testing to determine terminal velocity.)

The scope of this phase is dependent on the level of data provided by the OEM.

Impact testing: Perform controlled testing of the sUA, an 11 ft-lbf rigid object, and a 25 ft-lbf rigid object.

Laceration testing: Perform laceration testing with a skin surrogate and representative impact characteristics. 

Analyze results from Phase 2 for compliance with the thresholds in the Operations Over People rule. 

Determine if testing revealed any additional required mitigations or potential safety defects. 

Freqently Asked Questions

Is my aircraft a good candidate for this MOC?

Estimating injury severity without testing is difficult, but in general good candidate aircraft:

  • are lightweight and frangible
  • utilize specific flight modes (not changed in flight) that limit the flight envelopes to reduce the impact energy
  • reduce laceration potential with blade guards, propeller design and/or motor fail safes

What types of aircraft are not good candidates for this MOC?

  • Aircraft weighing over 20 lbs.
  • Because the relevant industry consensus standards are not yet available, aircraft utilizing parachute systems to reduce kinetic energy are not eligible at this time.

What will an OEM need to provide for testing?

In Phase 1A – historical failure modes and associated data (this is not required but will reduce costs).

In Phase 1B, if needed – an operational UAS for assessing failure modes.

In Phase 2 – Approximately ten UAS for impact and laceration testing. (Note: The aircraft provided for impact testing must possess all physical characteristics of the operational aircraft but do not actually have to be functional; the aircraft provided for laceration testing must be functional.)  

How long will testing take? 

Depending on the degree of supplemental testing required in Phase 1B, the assessment is expected to take between 3 and 4 months.

Contact

Robert Briggs
Chief Engineer
(540) 231-9373
rcbriggs@vt.edu