Federal law requires that engine noise be kept below a certain level. They are also the only product sold by the company. ABS is the only U.S. company that has received FAA permission to design and sell a Stage 3 hush kit for the DC-9. US Airways, Northwest, and TWA declined comment. Because the company has a monopoly on Stage 3 hush kits for commercial DC-9s, and because the government is requiring all airlines to purchase the kits, they add up to an extremely lucrative business.
ABS denies covering up anything.
We are proud of our product, its in-service record, the professionalism, dedication, and diligence of the team we have in place to support our product and comply with all regulatory requirements. The FAA is the federal agency charged with maintaining air safety. While it has opened an investigation into the hush kits, it has not acknowledged that the hush kit may be unsafe. In fact, some have charged that the FAA has been unnecessarily slow to respond to concerns about the kits. Sources familiar with the FAA suggest that, rather than ensuring the public's safety, the FAA may be more interested in protecting the careers of FAA officials who should have been investigating the hush kits.