[Federal Register Volume 74, Number 245 (Wednesday, December 23, 2009)]
[Rules and Regulations]
[Pages 68131-68132]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-30436]



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  Federal Register / Vol. 74, No. 245 / Wednesday, December 23, 2009 / 
Rules and Regulations  

[[Page 68131]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE299; Special Conditions No. 23-239-SC]


Special Conditions: Cessna Aircraft Company, Model 525C; High 
Fuel Temperature

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

-----------------------------------------------------------------------

SUMMARY: These special conditions are issued for the Cessna Aircraft 
Company, model 525C airplane. This airplane will have a novel or 
unusual design feature(s) associated with high fuel temperature. The 
applicable airworthiness regulations do not contain adequate or 
appropriate safety standards for this design feature. These proposed 
special conditions contain the additional safety standards that the 
Administrator considers necessary to establish a level of safety 
equivalent to that established by the existing airworthiness standards.

DATES: Effective Date: December 16, 2009.

FOR FURTHER INFORMATION CONTACT: Peter L. Rouse, Federal Aviation 
Administration, Aircraft Certification Service, Small Airplane 
Directorate, ACE-111, 901 Locust, Kansas City, Missouri, 816-329-4135, 
fax 816-329 4090.

SUPPLEMENTARY INFORMATION:

Background

    On August 9, 2006, Cessna Aircraft Company applied for an amendment 
to Type Certificate Number A1WI to include the new model 525C (CJ4). 
The model 525C (CJ4), which is a derivative of the model 525B (CJ3), 
currently approved under Type Certificate Number A1WI, is a commuter 
category, low-winged monoplane with ``T'' tailed vertical and 
horizontal stabilizers, retractable tricycle type landing gear and twin 
turbofan engines mounted on the aircraft fuselage. The maximum takeoff 
weight is 16,950 pounds, the VMO/MMO is 305 KIAS/
M 0.77 and the maximum altitude is 45,000 feet.
    The Cessna model 525C (CJ4) fuel tank system is similar to other 
Cessna model 525 designs which use the Williams FJ44 series of engine. 
The fuel tank system is configured to reject engine heat through the 
airplane fuel tank system by using an engine oil/fuel heat exchanger. 
Certified as part of the engine, the engine oil/fuel heat exchanger 
cools the oil and heats the fuel. Over time, the engine manufacturers 
have optimized the design, size, placement, and space management of the 
oil/fuel heat exchanger such that today's engines now reject more heat 
back into the airplane fuel tank system than has existed in the past. 
As can be seen by the chart below, we are now exposing the fuel tank 
system and airplane to temperatures above the critical temperature test 
requirements of Sec. Sec.  23.961 and 23.965(d), which has been the 
universal FAA standard for fuel system hot weather operations and fuel 
tank test and evaluation since 1950.

----------------------------------------------------------------------------------------------------------------
                                                                                                        IM Max.
                                                                                                       fuel pump
                                                                        Motive   Fuel tank  Fuel pump    inlet
             Aircraft model                      Engine model            flow     ([deg]F)    inlet      temp.
                                                                       ([deg]F)              ([deg]F)     (sea
                                                                                                         level)
----------------------------------------------------------------------------------------------------------------
525, CJ1+...............................  FJ44-1AP..................        205        115        165        255
                                                                                                          [deg]F
525A, CJ2...............................  FJ44-2C...................        230        140        188        200
                                                                                                          [deg]F
525B, CJ3...............................  FJ44-3A...................        202        117        155        200
                                                                                                          [deg]F
----------------------------------------------------------------------------------------------------------------

    14 CFR part 23 certification experience to date has shown that fuel 
system hot weather certification testing with 110 [deg]F fuel 
temperatures is adequate for fuel system operations for fuel tank 
temperatures characterized by ambient air temperatures, including 
cooling, as a result of the atmospheric temperature lapse rate. Heating 
of the fuel that increases the airplane fuel tank system operational 
temperatures introduces a number of fuel tank system and airplane 
concerns. Each must be shown to be acceptable. Compliance by design 
(i.e., lack of ability to shutoff the engine motive flow) may be 
utilized although associated type certificate data sheet information 
may also be necessary to assure future system changes are compliant. 
The following are those concerns:
    [cir] Evaluation of engine, fuel tank system and airplane 
performance and engine compatibility with elevated fuel tank system 
temperatures. [Sec.  23.901, paragraphs (e)(1) and (e)(2); and 
Sec. Sec.  23.939(a) and 23.951(a)]
    [cir] Evaluation of fuel tank system and airplane performance due 
to fuel degradation and resultant by-products at elevated fuel tank 
system temperatures. [Sec. Sec.  23.961, 23.939(a), 23.993(e), 23.1301, 
and 23.1529)]
    [cir] Evaluation of fuel tank system and airplane performance and 
engine compatibility due to the higher vapor/liquid ratios with 
elevated fuel tank system temperatures. [Sec. Sec.  23.903(f) and 
23.951(a); Sec.  23.955, paragraphs (a) and (f); and Sec. Sec.  23.961 
and 23.1301]
    [cir] Evaluation of fuel tank system and airplane performance and 
engine compatibility, due to the solubility of water and potential for 
greater microbial growth with elevated fuel tank system temperatures. 
[Sec. Sec.  23.951(c) and 23.971]
    [cir] Evaluation of fuel tank system and airplane performance due 
to elevated fuel tank system material temperatures and surrounding 
structure compatibility. [Sec. Sec.  23.613(c), 23.963(a), 23.965(d), 
and 23.993(e)]

[[Page 68132]]

    [cir] Evaluation of fuel tank system component qualification as a 
result of elevated fuel tank system temperatures. [Sec. Sec.  23.1301, 
and 23.1309]
    [cir] Evaluation of service/maintenance instructions, activities, 
and personnel due to elevated fuel tank system temperatures. [Sec.  
23.1529].

Type Certification Basis

    Under the provisions of Sec.  21.101, Cessna Aircraft Company must 
show that the model 525C meets the applicable provisions of the 
regulations incorporated by reference in Type Certificate Number A1WI 
or the applicable regulations in effect on the date of application for 
the change to the model 525C. The regulations incorporated by reference 
in the type certificate are commonly referred to as the ``original type 
certification basis.'' In addition, the certification basis includes 
exemptions, if any; equivalent level of safety findings, if any; and 
the special condition adopted by this rulemaking action.
    If the Administrator finds that the applicable airworthiness 
regulations in 14 CFR part 23 do not contain adequate or appropriate 
safety standards for the model 525C because of a novel or unusual 
design feature, special conditions are prescribed under the provisions 
of Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the model 525C must comply with the fuel vent and exhaust 
emission requirements of 14 CFR part 34 and the noise certification 
requirements of 14 CFR part 36.
    Special conditions, as appropriate, as defined in Sec.  11.19, are 
issued in accordance with Sec.  11.38, and become part of the type 
certification basis in accordance with Sec.  21.101(b)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporates the same novel or 
unusual design feature, or should any other model already included on 
the same type certificate be modified to incorporate the same novel or 
unusual design feature, the special conditions would also apply to the 
other model under the provisions of Sec.  21.101(a)(1).

Novel or Unusual Design Features

    The model 525C will incorporate the following novel or unusual 
design features:
    High Fuel Temperatures.

Discussion of Comments

    A notice of proposed special conditions No. 23-09-03-SC for the 
Cessna Aircraft Company, model 525C airplanes was published on 
September 1, 2009, 74 FR 45133. No comments were received, and the 
special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
model 525C. Should Cessna Aircraft Company apply at a later date for a 
change to the type certificate to include another model incorporating 
the same novel or unusual design feature, the special conditions would 
apply to that model as well under the provisions of Sec.  21.101(a)(1).
    Under standard practice, the effective date of final special 
conditions would be 30 days after the date of publication in the 
Federal Register; however, as the certification date for the Cessna 
Aircraft Company, model 525C is imminent, the FAA finds that good cause 
exists to make these special conditions effective upon issuance.

Conclusion

    This action affects only certain novel or unusual design features 
on one model of airplanes. It is not a rule of general applicability, 
and it affects only the applicant who applied to the FAA for approval 
of these features on the airplane.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

Citation

0
The authority citation for these special conditions is as follows:

    Authority:  49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and 
21.17; and 14 CFR 11.38 and 11.19.

The Special Conditions

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for Cessna Aircraft Company, model 525C 
airplanes.
    1. SC Sec.  23.961:
    Instead of compliance with Sec.  23.961, the following apply:
    Each fuel system must be free from vapor lock when using fuel at 
its critical temperature, with respect to vapor formation, when 
operating the airplane in all critical operating and environmental 
conditions for which approval is requested. For turbine fuel, the 
initial temperature must be 110 [deg]F, -0[deg], +5 [deg]F or the 
maximum outside air temperature for which approval is requested or the 
fuel tank system temperature that is determined to be more critical.

    Issued in Kansas City, Missouri on December 16, 2009.
Kim Smith,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. E9-30436 Filed 12-22-09; 8:45 am]
BILLING CODE 4910-13-P