The following documents are required to be in the aircraft during flight. Airworthiness certificate, registration, radio operators permit (if outside the U.S.), operating limitations, and weight and balance. The mnemonic ARROW is often used to remember these documents.
R-Radio Operations Permit (not required in U.S.)
O-Operating Limitations (included within POH/AFM or placards)
W-Weight and Balance (generally included within the POW/AFM)
The airworthiness certificate does not expire as long as the aircraft is maintained in airworthy condition. To maintain it in airworthy condition, an annual inspection must be completed and compliance with applicable airworthiness directives (ADs) is required. The registration must be current and it expires every 3 years. If operating internationally, a radio operator’s permit is required. A radio operator’s permit is not required if operating solely in the U.S.
The “W” in the ARROW is not clearly outlined in 14 CFR 91. Part 91.9 states to operate within limitations and the approved flight manual (or alternative) must be in the helicopter. The regulations governing helicopter certification, 14 CFR 27, requires that the aircraft weight limitations (14 CFR 27.25) and the center of gravity (CG) envelope (14 CFR 27.27) are to be established and that these limits are to be included as operating limitations (14 CFR 27.1519). As such, the helicopter’s weight and the W/B or CG limits must be in the helicopter as they are limitations. However, the actual W/B for a specific flight does not need to be in the helicopter, but the W/B should be calculated for each flight to demonstrate the flight is operated within the limitations (14 CFR 91.9).
14 CFR 91.9 – Civil aircraft flight manual, marking, and placard requirements
14 CFR 91.203 – Civil aircraft: Certifications required
14 CFR 47.40 – Registration expiration and renewal
14 CFR Part 27 – Airworthiness Standards: Normal Category Rotorcraft
14 CFR 27.25 Weight limits (requires establishment of maximum weight)
14 CFR 27.27 Center of gravity limits (requires establishment of CG envelope)
14 CFR 27.1519 Weight and center of gravity (W/B are established as operating limitations)