Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Sikorsky Aircraft Corporation Model S-76D helicopters. This proposed AD was prompted by reports that certain Thales global positioning system (GPS) satellite based augmentation system (SBAS) receivers provided, under certain conditions, erroneous outputs on aircraft positions. This proposed AD would require replacing affected GPS receivers and prohibit installing those GPS receivers. The FAA is proposing this AD to address the unsafe condition on these products.