Exemption No. 10089

UNITED STATES OF AMERICA DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION RENTON, WASHINGTON 98057-3356

In the matter ofthe petition of Cessna Aircraft Company for anexemption from § 25.1447(c)(1) of Title 14, Code ofFederal Regulations Regulatory Docket No. FAA-201 0-0290

GRANT OF EXEMPTION Byletter L390-1 0-0656, dated March 1,20to, Ms. Donna DeBuhr onbehalf ofMr. Carlos Ayala, Type Certification Organization Designation Authorization Administrator, Cessna Aircraft Company, One Cessna Boulevard, P.O. Box 7704, Wichita, Kansas, 67277-7704, petitioned for an exemption from 

### § 25.1447(c)(1) ofTitJe 14, Code ofFederal Regulations (14 CFR). The proposed exemption, ifgranted, would pernlit relief from the requuement that oxygen dispensing units be automatically presented to occupants before the cabin pressure altitude exceeds 15,000 feet on Cessna Model 680 airplanes. The petitioner requests relief from the following regulations: Section 25.1447(c)(I) requires, inpart, that an oxygen dispensing unit must he connected

, to oxygen supply terminals immediately available to each occupant, wherever seated. 1

# 1 certification for operation above 30,000 feetis requested, the dispensing units providing the required oxygen flow must he automatically presented to the occupants before the I cabin pressure altitude exceeds 15,000 feet, and the crew must beprovided with amanual means ofmaking the dispensing units inunediately available inthe eveot offailure ofthb automatic system. The petitioner supports its request with the following: The following material is quoted from Cessna's petition. "A new airport is under construction inNagqu, China inthe northwest portion ofthe Qinghai-Tibet Plateau. This airport is scheduled tobe-completed in2010 and has alanding field elevation (LFE) of 14,639 feet above sea level. The customer has requested

the aircraft be capable ofoperations atthis and other airports with field elevation above 14,000 feet (with anticipated barometric pressure variations) up to 15,000 feet. Inorder forthe Model 680 Sovereign to provide the additional capability for landing atairports up to 15,000 feetpressure altitude, the Cabin Pressure Control System (CPCS) and Passenger Oxygen Control System (POCS) will be modi_fledto allow the cabin internal pressure altitude to reach ashigh as 15,150 +/- 150feet during ">14K" operations. Manual control ofthe oxygen system isnot affected and can be activated atany time the crew deems necessary. Public Interest Statement: Cessna's leadership position inthe global business jet market isdue to the efforts ofits nearly eight lhousand employees inmanufacturing plants, completion centers, and service centers across the United States. This further includes the many vendors located across the United States that provide the numerous aircraft pieces such as avionics, oxygen components, as well as the modified CPCS components that would be used forthe aircraft to operate atthis high elevation. Cessna competes for new business all over the world. Although the current economy has slowed Cessna is striving hard to gain international markets for itsbusiness jets. This increased market directly affects the viability of Cessna and would aid inthe stabilization ofthejob market as well as the growth ofthe American economy, which isdirectly inthe interest ofthe public. Supporting Information: The oxygen mask presentation at 15,750 +/- 250 feet is only selected when a ">14K" switch is activated by the pilot. An indication light indicating that the aircraft is in ">14K" mode is also provided. This feature assists inlimiting use ofthis mode to conditions when the airplane will operate from airfie-Idswith anelevation greater than 14,000 feet. The activation point forthe cabin altitude warning is also shifted with the same switch to avoid nuisance alerts when operating to and from airports atan altitude greater than 14,000 feet. Appropriate procedures will be provided inthe Airplane Flight Manual to address proper operation ofthe ">14K" switch function. These features will have the flight crew select this function when descending to land atan airfield elevation greater than 14,000 feet and to reselect the ">14K" switch back to the «Normal" mode when climbing after takeoff fTOm an airport with a field elevation greater than 14,000 feet. The procedure will mimmize the time the aircraft is inthe elevated altitude tothat required to safely land and/or takeoff from airports with a field elevation greater than 14,000 feet."

2Feder-al Register publication

A summary ofthe petition was not published inthe Federal Register. The FAA determined that good cause existed forwaiving the publication requirement because this exemption would not set aprecedent. The FAA's analysis The FAA considers that granting the petition is inthe public interest for the reasons stated by the petitioner andbecause this exemption is effectively identical to previously granted exemptions to §25.1447(c)(I). The petitioner requests an exemption for Cessna Model 680 airplanes and seeks relief from the requirement of § 25.1447(c)(I), which states that oxygen dispensing units must be automaticaHy presented to occupants before the cabin pressure altitude reaches 15,000 feet. Arequirement fdr automatic presentation ofmasks for airplanes certificated to operate above 30,000 feet originat6d in §4b.651 (d)(3)(i) ofthe Civil Aviation Regulations (CAR) and was carried over as 

# I § 25.1447(c)(I) when part 25 was caddied. The CAR requirement did not specify the maximum cabin altitude pressure allowed prior topresentation. The requirement that the oxygen dispensing units be automatically presented before the cabin pressure altitude reaches 15,000 feet was added atAmendment 25-41, effective September 1, 1977. For operation ofthe Cessna Model 680 airplane into and out ofan airport with alanding field above 14,000 feet, the flightcrew must select the 

### ">14K" position on the airport elevation selection switch. This results in automatic deployment oftbe passenger oxygen masks when the cabin pressure altitude is 15,750 ±250 feet. This feature is necessary to reduce the occurrence of inadvertent deployment ofoxygen masks.



### 3The FAA's decision

Inconsideration ofthe foregoing, Ifind that agrant ofexemption is in the public interest. Therefore, pursuant tothe authority contained in49 U.S,c. 

### §§401 (3 and 44701, delegated tome by the Administrator, Cessna Aircraft Company is granted anexemption, forCessna Model 680 airplanes, from the requirement of § 25.1447(c)( 1)to automatically present oxygen dispensing units to occupants before the cabin pressure altitude exceeds 15,000 feet. Instead, this grant of exemption will permit oxygen dispensing units tobe automatically presented atcabin pressure altitudes of 15,750 ±250 feetwhen operating into and out of airports at altitudes above 14,000 feet. Issued in Renton, Washington, on 

### JUN 30 2010 

# /~a

Todd Dixon Acting Manager, Transport Airplane Directorate Aircraft Certification Service

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