14 CFR § 36.9 - Acoustical change: Propeller-driven small airplanes and propeller-driven commuter category airplanes.
---
identifier: "/us/cfr/t14/s36.9"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 36.9 - Acoustical change: Propeller-driven small airplanes and propeller-driven commuter category airplanes."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "36.9"
section_name: "Acoustical change: Propeller-driven small airplanes and propeller-driven commuter category airplanes."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "C"
subchapter_name: "AIRCRAFT"
part_number: "36"
part_name: "NOISE STANDARDS: AIRCRAFT TYPE AND AIRWORTHINESS CERTIFICATION"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 4321 49 U.S.C. 106(f), 40113, 44701-44702, 44704, 44715; sec. 305, Pub. L. 96-193, 94 Stat. 50, 57; E.O.11514, 35 FR 4247, 3 CFR, 1966-1970 Comp., p. 902."
regulatory_source: "Docket No. 9337, 34 FR 18364, Nov. 18, 1969, unless otherwise noted."
cfr_part: "36"
---
# 36.9 Acoustical change: Propeller-driven small airplanes and propeller-driven commuter category airplanes.
For propeller-driven small airplanes in the primary, normal, utility, acrobatic, transport, and restricted categories and for propeller-driven, commuter category airplanes for which an acoustical change approval is applied for under § 21.93(b) of this chapter after January 1, 1975, the following apply:
(a) If the airplane was type certificated under this part prior to a change in type design, it may not subsequently exceed the noise limits specified in § 36.501 of this part.
(b) If the airplane was not type certificated under this part prior to a change in type design, it may not exceed the higher of the two following values:
(1) The noise limit specified in § 36.501 of this part, or
(2) The noise level created prior to the change in type design, measured and corrected as prescribed in § 36.501 of this part.
[Amdt. 36-16, 53 FR 47400, Nov. 22, 1988; 53 FR 50157, Dec. 13, 1988; Amdt. 36-19, 57 FR 41369, Sept. 9, 1992]