NFPA has determined regarding grounding aircraft during refueling/defueling:

• A. It has no effect on equalizing static electrical potential between aircraft and refueler
• B. It is required for safety
• C. It should be avoided due to potential arcing
• D. It improves fuel accounting

Answer: (A)

Static electricity control in refueling hinges on bonding two conductive surfaces so they share the same electrical potential. The direct bond between the aircraft and the refueling equipment provides a low-resistance path for any charge to flow between them and equalize their potential. Grounding them to earth, by itself, does not determine or guarantee this equalization, because the important path is the bond directly between the two bodies, not a separate earth ground. NFPA’s guidance reflects that distinction: grounding has no effect on equalizing static potential between the aircraft and the refueler. The key safety measure is bonding, not relying on earth grounding. The other options miss this point or relate to aspects (safety, arcing, fuel accounting) that aren’t the NFPA focus for this specific question.