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breathing requires physical effort to exhale and minimal effort to inhale. This reversal of the
normal breathing cycle can lead to hyperventilation. Training of passengers to use pressure
breathing equipment safely is considered impractical. The FAA determined that an acceptable
means of compliance for the fixed and portable oxygen systems used by flight attendants and
passengers would be to install oxygen equipment that is certificated to 40,000 feet and limit
exposure to the reduced pressure environment above 40,000 feet via airplane descent
performance. The FAA believes that, ultimately, occupant survival during a decompression
event depends upon swift descent to a lower altitude. In its review of the petitioner’s airplane
descent profile, the FAA finds that the A380-800 can descend at acceptable rates.
6. Conclusion of FAA analysis
Permitting airplanes to fly above 40,000 feet does offer real and tangible benefits to the
aerospace industry, the traveling public, and the U.S. economy by reducing congestion,
improving fuel economy, and reducing pollution. If compliance with § 25.841 at Amendment
25-87 were to limit airplanes operations to a maximum altitude of 40,000 feet, it would impose a
significant disadvantage on newly designed airplanes that have many safety advantages over
older airplanes currently allowed to operate at higher altitudes. This would delay the
introduction of these airplanes and the benefits of their more advanced technology.
Based upon its evaluation of the data and analysis provided by Airbus, the FAA has determined
that there is sufficient justification for a partial grant of exemption from § 25.841(a)(2)(i) and (ii).
This partial grant of exemption takes into account operating rules in 14 CFR parts 91, 121 and
135 which require (a) that one pilot wear and use his oxygen mask when operating above 41,000
feet altitude and (b) that an adequate quantity of oxygen is provided for crew operations. This
partial grant of exemption is also premised on the condition that—in the Airplane Maintenance
Manual—the airplane manufacturer and the airline operator include any required maintenance
and checks of supplemental oxygen systems prior to each flight. In addition, this partial grant of
exemption is premised on the condition that—if dispatch is deemed appropriate with a
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malfunctioning system that is required to ensure that the airplane is capable of performing an
emergency descent (i.e., spoilers fully deployed, if appropriate; maximum descent rate;
maximum operating limit VMO/MMO speed)—then the Master Minimum Equipment List (MMEL)
must limit dispatch to a maximum flight altitude of 40,000 feet, unless other regulations or
limitations require a lower altitude. Though VMO/MMO is normally the best speed for a rapid
decompression descent, the pilots should follow the recommended emergency descent
procedures in the AFM.
The applicable rapid decompression procedures for the flightcrew must be included in the
emergency procedures section of the Airplane Flight Manual. This information should also be
included in the Airbus Flight Crew Operating Manual. Note that initial and recurrent emergency
training for all crewmembers, in accordance with §§ 121.397, 121.417, and 121.427, must
include training for a rapid decompression and donning of oxygen masks.
The Partial Grant of Exemption
In consideration of the foregoing, I find that a partial grant of exemption is in the pubic interest
regarding 14 CFR 25.841(a)(2)(i), and 25.841(a)(2)(ii) as amended by Amendment 25-87.
Therefore, pursuant to the authority contained in 49 U.S.C. 40113 and 44701, delegated to me by
the Administrator, the petition of Airbus for an exemption from the requirement of
14 CFR 25.841(a)(2)(i), and 25.841(a)(2)(ii), as amended by Amendment 25-87, is granted.
Regarding the provisions of § 25.841(a)(3), the petitioner complies with the regulation, since its
analysis did consider fuselage structure, engine failures, and system failures. Therefore, relief
from this requirement is not necessary.
The partial grant of exemption from § 25.841(a)(2)(ii) will permit cabin pressure altitude to
exceed 40,000 feet for 1 minute (but not to exceed 43,000 feet for any duration) after
decompression from any uncontained engine failure condition not shown to be extremely
improbable. The partial grant of exemption from § 25.841(a)(2)(i) will permit cabin pressure
altitude to exceed 25,000 feet for more than 2 minutes (but not more than 3 minutes) after
decompression from any uncontained engine failure condition not shown to be extremely
improbable, allowing time for the airplane to descend from an altitude of 43,000 feet to 25,000
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