In testimony before the House aviation subcommittee yesterday, DOT Inspector General Calvin Scovel told lawmakers that user acceptance and voluntary equipage are the keys for ADS-B to be fully successful. While the FAA will mandate usage of “ADS-B Out” for most classes of controlled airspace by 2020, it expects that airspace users will voluntarily equip with additional capabilities associated with “ADS-B In.” Scovel said the FAA negotiated a “robust” $1.8 billion contract with ITT but warned that it needs “proper execution and enforcement.” He said stakeholders are concerned that ADS-B could become another situation where some industry members equip and the FAA never follows through with the requisite ground infrastructure or mandate. The agency canceled a microwave landing system in the 1990s because of industry concerns and opposition, and more recently it dropped the controller-pilot datalink communications program in 2003 because of uncertain benefits, technical problems and cost-growth issues.