May 29, 2019
The FAA recently published a long-awaited advisory circular (AC) to help operators develop their weight and balance (W&B) control programs, but the document may lead to additional headaches for business aviation.
AC 120-27F has been in development since 2014. Industry stakeholders, including NBAA, noted significant concerns with prior drafts that removed published standard weights tables long used by operators to estimate passenger and cargo weight to determine the aircraft’s load and center-of-gravity (CG).
Previous versions of the AC included tables with values derived from the National Health and Nutrition Examination Survey (NHANES) conducted by the U.S. Centers for Disease Control. While AC 120-27F also permits the use of NHANES data, it no longer publishes the determined weights; instead, users must derive average weights from NHANES information and input those figures on a supplied Table (3-1) although the AC offers no guidance for doing so.
In lieu of NHANES data, the AC allows operators to “survey” their passengers or use actual weights. Cary Robins, a member of the Society of Aircraft Performance and Operations Engineers (SAPOE), which promotes flight safety and efficiency through knowledge of aircraft performance and weight and balance principles, noted that neither option is particularly attractive for business aviation operators.
“You typically don’t want to ask how much your passengers weigh, or have them get on scales,” said Robins, who is also with NBAA member company American Aeronautics and participates in the FAA’s Operations Specifications (OpSpec) Working Group. “That is why standard weights have always been used, without issue, to alleviate pressure on the flight crew when dealing with safety and compliance requirements.”
AC 120-27F also does not include standard baggage weights, again requiring the operator to conduct a survey or weigh baggage, including personal items such as briefcases, purses and laptop bags transported in the cabin.
Robins added that operators utilizing OpSpecs, specifically A097 for small cabin aircraft, must also “curtail the aircraft CG envelope as prescribed in AC 120-27 (as revised) Appendixes 3 and 4” when utilizing standard average weights. However, those appendixes no longer exist in AC 120-27F.
“The FAA is quick to note that advisory circulars are not regulatory, but that doesn’t change a carrier’s OpSpec that refers directly back to the AC to define their W&B program,” he said.
Stakeholders supplied comments to the FAA on AC 120-27F, and the current version includes a form to submit suggestions or feedback, an option Brian Koester, NBAA senior manager for flight operations and regulation, recommended operators utilize.
“This situation remains far from straightforward,” Koester said. “NBAA previously suggested involving industry through a working group to resolve these issues, and we intend to raise these concerns again in our future meetings with FAA personnel.”
Robins added that SAPOE is also developing possible solutions and recommendations for handling the changes in the AC.