The U.S. Office of Special Counsel (OSC) received a whistleblower disclosure concerning the use of a risk-based rule by the Transportation Security Administration's (TSA) Secure Flight program that may create a vulnerability in aviation security. We assigned our Office of Inspections team currently assessing Security Enhancements to the TSA Pre?™ Initiative to review this allegation. We interviewed the whistleblower and TSA senior officials involved in the risk-based rule decision-making process. We also analyzed documentation regarding these rules to determine whether an aviation security vulnerability exists.