[Federal Register: January 23, 2008 (Volume 73, Number 15)]
[Proposed Rules]
[Page 3881-3882]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr23ja08-9]
========================================================================
Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
========================================================================
[[Page 3881]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. CE280; Notice No. 23-07-05-SC]
Special Conditions: Embraer S.A., Model EMB-500; High Fuel
Temperature
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
-----------------------------------------------------------------------
SUMMARY: This notice proposes special conditions for the Embraer S.A.,
Model EMB-500 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: Comments must be received on or before February 22, 2008.
ADDRESSES: Mail comments on this proposal in duplicate to: Federal
Aviation Administration, Regional Counsel, ACE-7, Attention: Rules
Docket, Docket No. CE280, 901 Locust, Room 506, Kansas City, Missouri
64106, or deliver them in duplicate to the Regional Counsel at the
above address. Mark comments: CE280. You may inspect comments in the
Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4
p.m.
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:
Comments Invited
Interested persons are invited to participate in the making of
these proposed special conditions by submitting such written data,
views, or arguments as they may desire. Identify the regulatory docket
or notice number and submit them in duplicate to the address specified
above. All communications received on or before the closing date for
comments will be considered by the Administrator. The proposals
described in this notice may be changed in light of the comments
received. All comments received will be available in the Rules Docket
for examination by interested persons, both before and after the
closing date for comments. A report summarizing each substantive public
contact with FAA personnel concerning this rulemaking will be filed in
the docket. If you wish the FAA to acknowledge receipt of the comments
submitted in response to this notice, include with those comments a
self-addressed, stamped postcard on which the following statement is
made: ``Comments to CE280.'' The postcard will be date stamped and
returned to the commenter.
Background
On October 5, 2005, Embraer S.A. applied for a type certificate for
their new Model EMB-500. The Model EMB-500 is a normal 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. Its design characteristics include a
predominance of metallic construction. The maximum takeoff weight is
9,965 pounds, the VMO/MMO is 275 KIAS/M 0.70 and
maximum altitude is 41,000 feet.
Fuel temperatures on the Embraer EMB 500 are higher than envisioned
by 14 CFR part 23. The rule governing fuel system hot weather operation
is 14 CFR part 23, Sec. 23.961, and the rule requires the following:
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] or the
maximum outside air temperature for which approval is requested,
whichever is more critical.
During other airplane certification projects, the fuel system
temperatures associated with the PW600 series turbofan engines were
much higher than those previously encountered on other engines. The
engine oil/fuel heat fuel system includes an exchanger that cools the
oil and heats the fuel. Consequently, the motive flow fuel that is
returned to the airplane from the engine is hot and heats the airplane
wing fuel and tank. As a result, on the PW615F, the engine inlet
maximum fuel temperature was increased from a development value of 126
[deg]F (52 [deg]C) to an initial (Transport Canada) certification value
of 172 [deg]F (78 [deg]C) for kerosene type fuels.
Initial concerns regarding the safe operation of the airplane with
fuel temperatures significantly greater than 110 [deg]F are identified
as:
Fuel degradation with resultant byproducts at high
temperatures.
Operation with the higher vapor liquid ratios.
Fuel system component qualification at the higher
temperatures.
Solubility of water in fuel.
Microbial growth.
Fuel tank material/surrounding structure compatibility
with the elevated temperatures.
Service and maintenance personnel susceptibility to burns.
An initial review of FAA experience regarding airplane fuel
temperatures identifies that for large part 25 aircraft, fuel
temperature upper limits are characterized by Sec. 25.961 values, i.e.
110-120 [deg]F. Operationally, the buildup of vapor pockets within fuel
lines has been an issue from this perspective for large transport
category airplanes. A summary of the maximum engine inlet fuel
temperatures for engines used in part 23 and part 25 business jet
airplanes that are FAA certified follows:
------------------------------------------------------------------------
Sea level maximum inlet fuel
Engine model temperature
------------------------------------------------------------------------
PWC615F................................... 126 F (52 C) draft IM.
PWC615F................................... 172 F (78 C) Transport
Canada.
PWC615F................................... 190 F (88 C).
530A, 535A................................ 135 F (57 C).
545A...................................... 135 F (57 C).
305A...................................... 135 F (57 C).
308....................................... 135 F (57 C).
JT15D-4, -4B, -4D......................... 135 F (57 C).
FJ44-3A................................... 200 F (93 C).
FJ44-2A................................... 135 F (57 C).
FJ44-1B................................... 135 F (57 C).
TFE731-2/-3............................... 135 F (57 C).
[[Page 3882]]
TFE731-20................................. 135 F (57 C).
------------------------------------------------------------------------
CAR part 3, as amended to May 15, 1956, defined the maximum
anticipated summer air temperatures in Sec. 3.583; ``The maximum
anticipated summer air temperature shall be considered to be 100 [deg]F
at sea level and to decrease from this value at the rate of 3.6 [deg]F
per thousand feet above sea level.'' Concurrently, Sec. 3.438 required
that ``* * * fuel system features conducive to vapor formation shall be
demonstrated to be free from vapor lock when using fuel at a
temperature of 110 [deg]F under critical operating conditions.''
Building from CAR part 3, 14 CFR part 23 envisioned maximum fuel
temperatures at or near 110 [deg]F as set forth in 14 CFR part 23,
Sec. 23.961. The turbine fuel temperature requirement for hot weather
operation is 110 -0, +5 [deg]F, or the maximum outside air temperature
for which approval is requested, whichever is more critical. Engine
heat rejection such that the airplane fuel temperature is characterized
by engine heat rejection rather than ambient air temperature is a new
and novel design that was not envisioned by 14 CFR part 23.
14 CFR part 23 certification experience to date has shown that hot
weather certification testing with 110 [deg]F fuel temperatures is
adequate for fuel system operations for fuel tank fuel temperatures
characterized by ambient air temperatures including cooling as a result
of the atmospheric temperature lapse rate. Heating that increases the
airplane fuel system operational temperatures introduces several fuel
system 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.
A special condition for the higher fuel system temperatures of the
Embraer EMB 500 airplane is proposed. The special condition would
require the compliance to 14 CFR part 23, Sec. 23.961, fuel system hot
weather operation test temperature to be commensurate with the highest
fuel temperature expected at the maximum outside air temperature for
which approval is requested.
Type Certification Basis
Under 14 CFR part 21, Sec. 21.17, Embraer S.A. must show that the
Model EMB-500 meets the applicable provisions of 14 CFR part 23, as
amended by Amendments 23-1 through 23-55, thereto.
If the Administrator finds that the applicable airworthiness
regulations (i.e., 14 CFR part 23) do not contain adequate or
appropriate safety standards for the Model EMB-500 because of a novel
or unusual design feature, special conditions are prescribed under
Sec. 21.16.
In addition to the applicable airworthiness regulations and special
conditions, the Model EMB-500 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, and the FAA must issue a
finding of regulatory adequacy under section 611 of Public Law 92-574,
the ``Noise Control Act of 1972.''
Special conditions, as appropriate, as defined in Sec. 11.19, are
issued under Sec. 11.38, and become part of the type certification
basis under Sec. 21.17(a)(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, the special conditions would also apply to the
other model under Sec. 21.101(a)(1).
Novel or Unusual Design Features
The Model EMB-500 will incorporate the following novel or unusual
design features: High Fuel Temperatures.
Applicability
As discussed above, these special conditions are applicable to the
Model EMB-500. Should Embraer S.A. apply later 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 Sec. 21.101(a)(1).
Conclusion
This action affects only certain novel or unusual design features
on one model, Model EMB-500, 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
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 Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for the Embraer S.A. Model EMB-500 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 the highest fuel temperature expected at
the maximum outside air temperature for which approval is requested.
Issued in Kansas City, Missouri, on January 7, 2008.
John Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-1075 Filed 1-22-08; 8:45 am]
BILLING CODE 4910-13-P