Regulation Text
(a) No person may operate an airplane that conforms to an amended or supplemental type certificate issued in accordance with SFAR No. 41 for a maximum certificated takeoff weight in excess of 12,500 pounds unless within 1 year after issuance of the initial airworthiness certificate under that SFAR the airplane meets the compartment interior requirements set forth in § 25.853 (a), (b), (b-1), (b-2), and (b-3) of this chapter in effect on September 26, 1978.
(b) Thermal/acoustic insulation materials. For transport category airplanes type certificated after January 1, 1958:
(1) For airplanes manufactured before September 2, 2005, when thermal/acoustic insulation is installed in the fuselage as replacements after September 2, 2005, the insulation must meet the flame propagation requirements of § 25.856 of this chapter, effective September 2, 2003, if it is:
(i) Of a blanket construction or
(ii) Installed around air ducting.
(2) For airplanes manufactured after September 2, 2005, thermal/acoustic insulation materials installed in the fuselage must meet the flame propagation requirements of § 25.856 of this chapter, effective September 2, 2003.
[Docket 18334, 54 FR 34318, Aug. 18, 1989, as amended by Amdt. 91-279, 68 FR 45083, July 31, 2003; Amdt. 91-290, 70 FR 77752, Dec. 30, 2005]
The short answer
(14 CFR § 91.613) This section sets fire-related material standards for airplane compartment interiors, including SFAR No. 41 airplanes over 12,500 pounds that must meet § 25.853 requirements within one year of the initial airworthiness certificate, and thermal/acoustic insulation that must meet the § 25.856 flame-propagation requirements.
Research Notes
Common Questions
What does § 91.613 require for SFAR No. 41 airplanes?
An airplane conforming to an amended or supplemental type certificate issued under SFAR No. 41 for a maximum certificated takeoff weight over 12,500 pounds must meet the § 25.853 compartment interior requirements (in effect September 26, 1978) within one year after the initial airworthiness certificate is issued.
"No person may operate an airplane that conforms to an amended or supplemental type certificate issued in accordance with SFAR No. 41 for a maximum certificated takeoff weight in excess of 12,500 pounds unless within 1 year ... the airplane meets the compartment interior requirements set forth in § 25.853 (a), (b), (b-1), (b-2), and (b-3) ... in effect on September 26, 1978." — 14 CFR § 91.613(a)
When must thermal/acoustic insulation meet § 25.856 flame propagation requirements?
For transport category airplanes type certificated after January 1, 1958: airplanes manufactured before September 2, 2005 must meet § 25.856 when blanket-construction or air-duct insulation is installed as a replacement after September 2, 2005; airplanes manufactured after September 2, 2005 must meet it for all fuselage thermal/acoustic insulation.
"(2) For airplanes manufactured after September 2, 2005, thermal/acoustic insulation materials installed in the fuselage must meet the flame propagation requirements of § 25.856 of this chapter, effective September 2, 2003." — 14 CFR § 91.613(b)
Which insulation installations trigger the replacement rule for older airplanes?
For airplanes manufactured before September 2, 2005, the § 25.856 flame propagation requirement applies to replacement insulation that is of a blanket construction or installed around air ducting.
"the insulation must meet the flame propagation requirements of § 25.856 ... if it is: (i) Of a blanket construction or (ii) Installed around air ducting." — 14 CFR § 91.613(b)(1)
Angle of Attack is an aviation flight-training brand founded by Chris Palmer, a two-time Master Aviation Educator and Gold Seal CFI. We decode the FARs so pilots understand not just the words, but what they mean in the cockpit.
AOA's Decoded pages are plain-English interpretation for training and reference. They are not legal advice and do not replace the official regulation. Always confirm current requirements against the authoritative source before acting.