FAA Order 8130.34D — UAS Operating Limitation A-24
Appendix A · p. A-5
This UA is prohibited from flight with any externally mounted equipment that is not properly mounted and secured in a manner that will prevent in-flight detachment. The aircraft must be configured as documented in the aircraft’s flight test records or as allowed in the original manufacturer’s aircraft data. If relying on the manufacturer’s data, the aircraft must conform to the manufacturer’s design and be maintained with existing manufacturer’s maintenance and inspection instructions.
This limitation is only for other than former military aircraft.
Verify it yourself: the eyeball above opens the exact page of Order 8130.34D with this limitation highlighted.