All jet and transport-category airplanes with an mtow of 12,500 pounds or more for which application of a new type design is submitted on or after Jan. 1, 2006, will have to meet new noise certification levels.

The FAA’s final FAR Part 36 Stage 4 noise levels are a cumulative 10 EPNdB (effective perceived noise level in decibels) less than the current Stage 3 limits. They are based on the work of the International Civil Aviation Organization’s committee on aviation environmental protection, in which the FAA and the International Business Aviation Council are active members.

All business jets currently manufactured meet Stage 3 limits (by law), and nearly all would qualify to be recertified to meet Stage 4. Although the proposal doesn’t contain a Stage 4 retrofit requirement and the FAA said it has no plans to impose such a requirement, one of the committee’s recommendations called for a phaseout of Stage 3 airplanes with an mtow of more than 75,000 pounds by 2020.

Although there is not expected to be a Stage 4 retrofit requirement for business jets, just as there isn’t for Stage 3, some industry analysts believe the Stage 4 requirements will strengthen efforts by those who have been working to remove airport access by Stage 2 business jets, as well as launch new efforts to restrict access by Stage 3 business jets.

In the Stage 4 notice of proposed rulemaking, the FAA had noted that 25 years elapsed between the adoption of Stage 3 in 1975 and an all-Stage 3 airline fleet in December 1999.