[Federal Register Volume 74, Number 240 (Wednesday, December 16, 2009)]
[Rules and Regulations]
[Pages 66567-66570]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-29847]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE304; Special Conditions No. 23-244-SC]


Special Conditions: Embraer (Empresa Brasileira de Aeronautica 
S.A.), Model EMB-505; Automatic Inhibition of Ice Protection System

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Embraer model EMB-
505 airplane. This airplane will have a novel or unusual design 
feature(s) associated with operation of the airframe ice protection 
system. The applicable airworthiness regulations do not contain 
adequate or appropriate safety standards for this design feature. These 
special conditions contain the additional safety standards that the 
Administrator

[[Page 66568]]

considers necessary to establish a level of safety equivalent to that 
established by the existing airworthiness standards.

DATES: The effective date of these special conditions is December 8, 
2009. We must receive your comments by January 15, 2010.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Regional Counsel, ACE-7, Attn: Rules Docket 
No. CE304, 901 Locust, Kansas City, MO 64106. You may deliver two 
copies to the Regional Counsel at the above address. You must mark your 
comments: Docket No. CE304. 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: Paul Pellicano, Standards Staff, ACE-
111, Federal Aviation Administration, Small Airplane Directorate, 
Aircraft Certification Service, 901 Locust, Kansas City, MO 64106; 
telephone (404) 474-5558; facsimile (816) 329-4090.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice and 
opportunity for prior public comment hereon are impracticable because 
these procedures would significantly delay issuance of the approval 
design and thus delivery of the affected aircraft. In addition, 
although the substance of these special conditions has not been subject 
to the public comment process in prior instances, the FAA anticipates 
no adverse comments will be received. The FAA therefore finds that good 
cause exists for making these special conditions effective upon 
issuance.

Comments Invited

    We invite interested people to take part in this rulemaking by 
sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reason for any recommended change, and include supporting data. We ask 
that you send us two copies of written comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
about these special conditions. You can inspect the docket before and 
after the comment closing date. If you wish to review the docket in 
person, go to the address in the ADDRESSES section of this preamble 
between 7:30 a.m. and 4 p.m., Monday through Friday, except Federal 
holidays.
    We will consider all comments we receive by the closing date for 
comments. We will consider comments filed late if it is possible to do 
so without incurring expense or delay. We may change these special 
conditions based on the comments we receive.
    If you want us to let you know we received your comments on these 
special conditions, send us a pre-addressed, stamped postcard on which 
the docket number appears. We will stamp the date on the postcard and 
mail it back to you.

Background

    On October 9, 2006, Embraer applied for a type certificate for 
their new model EMB-505. The EMB-505, is a 9 seat, pressurized, 
retractable-gear, twin turbofan-powered aircraft. It will be certified 
in the commuter category with a takeoff gross weight of 17,968 pounds. 
The Embraer model 505 will be certified for flight in icing conditions 
and uses engine bleed air to provide ice protection for the wings and 
empennage. It will have an altitude capability of 45,000 feet.
    The ice protection system is designed to inhibit operation at 
altitudes above 30,000 feet or at high ambient temperatures (for 
example, above +8 [deg]C at altitudes up to 12,000 feet), even if there 
are ice accretions on the airframe. If the pilot selects the airframe 
ice protection on in these conditions, the airframe ice protection 
system operation will be inhibited and an annunciation will be provided 
to the pilot. The proposed procedure is to exit icing conditions. There 
is no means for the pilot to override the system and select the 
airframe ``anti-ice on'' in these conditions. Icing conditions can 
exist at altitudes where the model 505 wing and empennage ice 
protection system is inhibited. It must be shown that the Embraer model 
505 airplane can operate safely in icing conditions at altitudes above 
30,000 feet, or approval for flight in icing must be restricted to 
operations below that altitude. Since the certification icing standards 
defined in Appendix C of part 25 do not define icing conditions above 
30,000 feet, icing conditions standards above 30,000 feet and the 
standards to show safe operation must be defined.
    Although the intent of Sec.  23.1419 is for the airplane to safely 
operate in icing conditions, the regulation only requires that ``* * * 
the airplane must be able to safely operate in the continuous maximum 
and intermittent maximum icing conditions of part 25, Appendix C.'' 14 
CFR part 25, Appendix C lists atmospheric icing conditions for a 
maximum of 30,000 feet. However, icing conditions can exist above this 
altitude. For example, FAA technical report ADS-4, figure 1-21 includes 
three reported icing encounters above 30,000 feet. These examples 
include a severe icing encounter at 37,000 feet and a light icing 
encounter at 39,000 feet. These data were solicited from operators 
because the data that forms the basis of part 25, Appendix C were 
obtained with aircraft with an operational ceiling of 22,000 feet. FAA 
technical report ADS-4 concludes that icing above 30,000 is infrequent 
and not likely to be severe, and airplanes with ice protection systems 
designed to part 25, Appendix C ``will probably have no difficulties 
when icing is encountered at high altitudes.'' However, this assumes 
the ice protection system is available.
    The system inhibit at high outside air temperature is not an issue 
since ice accretion is not expected at these temperatures. Section 
23.1309 is adequate to assure adequate system reliability, in other 
words, the system will not be inhibited in conditions in which it is 
required.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, Embraer must show that the 
model EMB-505 meets the applicable provisions of part 23, as amended by 
Amendments 23-1 through 23-55 thereto, and the special conditions 
adopted by this rulemaking action.
    In addition, the certification basis includes certain ``exemptions, 
equivalent level of safety findings, and special conditions that are 
not relevant to the special conditions adopted by this rulemaking 
action.''
    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-505 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 EMB-505 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 Sec.  611 of Public Law 92-574, 
the ``Noise Control Act of 1972.''
    The FAA issues special conditions, as defined in Sec.  11.19, under 
Sec.  11.38 and they 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.

[[Page 66569]]

Novel or Unusual Design Features

    The model EMB-505 will incorporate the following novel or unusual 
design features: Due to the potential to overtemp the engines, the ice 
protection system is designed to inhibit operation at altitudes above 
30,000 feet or at high ambient temperatures (for example, above +8 
[deg]C at altitudes up to 12,000 feet with both bleed systems 
operating), even if there are ice accretions on the airframe. If the 
pilot selects the WINGSTAB switch ON in these conditions, the airframe 
anti-ice valves will remain closed. The pilot will receive a caution 
CAS message ``A-I WINGSTB OFF'' making the pilot aware that the wing 
and horizontal stabilizer anti-ice system (WHSAIS) is not operational. 
The proposed procedure is to exit icing conditions. There is no means 
for the pilot to override the system and select the airframe ``anti-ice 
on'' in these conditions. Icing conditions can exist at altitudes where 
the model 505 wing and empennage ice protection system is inhibited. It 
must be shown that the Embraer model 505 airplane can operate safely in 
icing conditions at altitudes above 30,000 feet, or approval for flight 
in icing must be restricted to operations below that altitude. Special 
conditions are required to define the icing conditions above 30,000 
feet and the standards to show safe operation above 30,000 feet after 
encountering icing conditions.

Discussion

    The special conditions define the ice accretions that Embraer must 
consider. These ice accretions include a climb through continuous 
maximum conditions, plus an encounter above 30,000 feet with the ice 
protection system off through a continuous maximum cloud or 
intermittent maximum cloud. Safe operation must be shown with the 
critical encounter. The encounters are through standard cloud lengths 
defined in Appendix C at the critical altitude determined by Embraer. 
The liquid water content is defined at the coldest temperature defined 
for continuous maximum and intermittent maximum, respectively, in part 
25, Appendix C. Although not defined in the special conditions, as is 
accomplished for icing certification, it is expected the median drop 
size will be chosen to provide the highest water catch on the wing 
leading edge.
    The special conditions provide two options--prohibit flight in 
icing conditions above 30,000 feet, or have no restriction above 30,000 
feet.
    The first option allows Embraer to prohibit flight in icing above 
30,000 feet. For this option, icing cues must be substantiated or an 
ice detector installed. The special condition requires an AFM 
limitation prohibiting flight in icing above 30,000 feet; however, a 
cockpit placard is also expected. Typically, there are no Subpart B 
requirements for airplanes with ice accretion if they are prohibited 
from flight in icing conditions. However, since the model EMB-505 is 
approved for flight in icing conditions for most of its operational 
envelope, it is necessary to have adequate stall warning if icing is 
inadvertently encountered above 30,000 feet. The requirement on stall 
warning must be the same as the requirement for pre-activation ice, as 
a minimum. The means of stall warning must be the same as for non-
icing, and the margin must be adequate. This is shown by showing 
stalling or large roll excursion can be avoided if the pilot delays 
recovery one second after stall warning in a one-knot-per-second 
deceleration, wings level and turning flight. The recovery procedure 
assumes the pilot will attempt to minimize altitude loss.
    The second option allows unrestricted flight in icing conditions 
above 30,000 feet. The requirements are the same as for flight in icing 
below 30,000 feet. The airplane must comply with Subpart B requirements 
with the defined ice accretions.
    The special conditions prohibit automatic inhibition of engine ice 
protection and also address the issue of ice shedding into the engines. 
After accreting ice above inhibit altitudes, airframe ice protection 
will be activated once the airplane descends below the inhibit 
altitude. Past experience has shown all the accreted ice tends to shed 
at once for thermal ice protections systems. The special conditions for 
the engines are necessary since loss of thrust from both engines is 
classified as a hazard for the EMB-505 class of airplane.

Applicability

    As discussed above, these special conditions are applicable to the 
model EMB-505. Should Embraer 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.

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 affects only the applicant who applied to the FAA for approval of 
these features on the airplane.
    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 Embraer 
EMB-505 is imminent, the FAA finds that good cause exists to make these 
special conditions effective upon issuance.

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 
14 CFR 11.38 and 11.19.

The Special Conditions

    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 Embraer EMB-505 airplanes.
    1. SC 23.1419:
    Instead of compliance with Sec.  23.1419, the Embraer EMB-505 must 
comply with the current version of Sec.  23.1419 and the following 
additional paragraphs:
* * * * *
    (e) If the wing or empennage anti-ice or de-icing systems are 
controlled in a manner that inhibit the system operation above certain 
altitudes automatically, with no means for the flight crew to override, 
the following applies:
    (1) Flight in icing conditions will be restricted to altitudes 
below those where the system cannot be manually activated.
    (i) Substantiated icing cues or an icing detector must be installed 
to allow exiting inadvertent icing encounters above the altitude where 
the system is automatically inhibited.
    (ii) There must be a limitation in the Airplane Flight Manual 
stating that the airplane is not certificated for flight in icing at 
altitudes above the altitude in which system operation is automatically 
inhibited.
    (iii) The stall warning must be provided by the same means as in 
non-icing conditions and must be shown to provide adequate margin to 
stall with the ice accretions defined in paragraphs (e)(2)(ii) and 
(e)(2)(iii).
    As an alternate to complying with paragraph (e)(1), the provisions 
of paragraph (e)(2) apply:
    (2) For certification without restrictions in icing conditions 
above

[[Page 66570]]

the system automatic shut off altitude, the airplane controllability, 
maneuverability, stability, stall characteristics and stall warning 
must not be less than required in part 23, Subpart B, with stall 
warning provided by the same means as in non-icing conditions, with the 
following ice accretions:
    (i) The ice shape(s) that would be on the airplane after a climb 
through the critical icing conditions of 14 CFR part 25, Appendix C, 
Figure 1.
    (ii) The critical ice shape(s) from paragraph (i) above, plus an 
exposure to one 17.4 nautical mile continuous maximum cloud at 
altitudes between the automatic shut off altitude feet and the maximum 
operating altitude with the ice protection system off. The ice shape(s) 
must be based on the liquid water content for the coldest temperature 
shown in 14 CFR part 25, Appendix C, Figure 1.
    (iii) The critical ice shape(s) from paragraph (i) above plus an 
exposure to one 2.6 nautical mile intermittent maximum cloud at 
altitudes between 30,000 feet and the maximum operating altitude with 
the ice protection system off. The substantiation will assume the 
liquid water content for the coldest temperature shown in 14 CFR part 
25, Appendix C, Figure 4.
    The AFM must contain appropriate procedures for activating the 
airframe ice protection system at altitudes where the system can be 
activated, and for exiting icing conditions at altitudes where the 
system is inhibited.
    (f) The engine anti-icing system must not be subject to the 
automatic shut off feature but must be operable at any altitude.
    (g) It must be shown that engine operation is not affected by ice 
shedding from the inboard wing, with the ice accretions defined in 
paragraph (e)(2), after the airplane has descended below the inhibit 
altitude.

    Issued in Kansas City, MO, on December 8, 2009.
Margaret Kline,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-29847 Filed 12-15-09; 8:45 am]
BILLING CODE 4910-13-P