1 **Exemption No. 10760** 

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

**- 3356** 

In the matter of the petition of
**LIVETV** for an exemption from § 25. 571(e)(1) of Title 14, Code of Federal Regulations **Regulatory Docket No. FAA** 
**- 20**  **13**
**- 03**  **73**

**GRANT OF**  **TIME**
**- LIMITED**  **EXEMPTION** By letter dated April 16 , 2013, Oscar Hernandez, Lead Certification Engineer, LiveTV, 8900 Hang ar Boulevard, Orlando, FL, 32827, petitioned the Federal Aviation Administration (FAA) for an exemption from the requirements of § 25.571(e)(1) of Title 14, Code of Federal Regulations (14 CFR). This exemption, if granted , would permit installation of Ka Band radomes on Airbus Model A32 1 airplanes that do not meet FAA bird

- strik e damage

- tolerance requirements. The petitioner requests that the exemption remain valid for one ye ar from the date that the Supplemental Ty

pe Certificate (STC) is issued. (The FAA will specify an exact date.) Within that time , the applicant would demonstrate full compliance to the applicable requirements. **The petitioner requests relief from the following regulation(s): Section 25.**  **571(e)(1)**

– Damage

- tolerance (discrete source) e valuation. The airplane must be capable of successfully

completing a flight during which likely structural damage occurs as a result of

– (1) Impact with a 4

- pound bird when the velocity of the airplane relative to the bird along the airplane ’ s flight path is equal to V c at sea level or 0.85V c at 8,000 feet, whichever is more critical

... This section defines required structural requirements for damage to the airframe from a bird strike. **The petitioner supports its request with the following**  **information:** This section quotes the relevant information from the petitioner ’ s request. The complete petition is available at the Department of Transportation ’ s Federal Docket Management Sy stem, on the Internet at http://regulati ons.gov , in Docket No. FAA

- 2013

- 03 73

.2

**Safety and Public Interest** The petition would not adversel y affect safety because of the extremely low probability of a bird strike as summarized below. This conclusion is supported by close to 10 million flight hours without a bird strike occurring to any L iveTV radome. These legacy radomes, installed on B

- 737s and A320s, are dimensionally identical and placed in the same relative airframe location, thus allowing LiveTV to combine their service experience to show an additional margin of safety. Moreover, the aircraft's frontal fuselage shadows the Ka Band radome due to the aircraft's angle of attack during all but the most extreme flight operations. Public interest to grant the exemption is supported by the fact that LiveTV is currentl y working closel y with the FAA on an airworthiness directive relating to the legacy radome which is experiencing in

- service fatigue cracks. Having the Ka radome available to replace the legacy

radome will support continued airworthine ss and therefore be in the public interest. The two radomes have similar geometry and profiles and consequently the Ka radome is no more susceptible to a bird strike event. **Radome Design** The design of the new Ka Band radome is an aerody namic shape, similar to previous designs, with minimal height. It is located on the crown of the fuselage and aft of the wing spar to reduce the aerodynamic influence on the original airframe. This location ensures that a bird strike event will not occur throughout the aircr aft ’ s normal flight operations due to the aircraft ’ s angle of attack (AOA). In addition to these phy sical characteristics the new radome incorporates engineering advances in composite materials and lessons learned based on LiveTV ’ s 13 years of experience i n radome design, manufacturing , and maintenance. LiveTV chose the radome design, its location on the aircraft and method of compliance for § 25.571 (e)(1) over 18 months ago

. A number of material tests, analy ses, and reports have been prepared on the radome specifically and most of the engineering needed for the Ka Band Connectivity

Sy stem has also been completed, placing this project in its final stages. As part of the ongoing certification efforts for the referenced project LiveTV submitted a Composite Rad ome Hazard Assessment (CRHA) report to the Chicago and Atlanta Aircraft Certification Office (ACO) to substantiate its position on the improbability of a bird strike to the radome based on an an gle of attack greater than 0.89 degrees. The CRHA was based, i n large part, on the 1978 preamble adopting § 25.571(e) in which the FAA recognize d that the word “likel y” (which also appears in the current rule) had a "substantive probability

connotation ...." (43 FR 46240, October 5, 1978). This statement supports L iv eTV's view that compliance with § 25.571(e) may be demonstrated by submitting a suitable probability anal ys is as recognized in other bird strike rules. However, after further review of the CRHA report the FAA informed LiveTV that additional substantiation for compliance with § 25.571(e) (1) , Amendment 25

- 132, was required

. Therefore, additional time is needed to re

- evaluate and substantiate the Ka radome design. Pending the accomplishment of this work the FAA indicated a willingness to consider granti ng an e xemption for a limited period.3

The affected operators have advised LiveTV that they will not make their aircraft available for the prototyp e installations unless an exemption has been granted. Accordingl y, LiveTV requests that the exemption b e issued as soon as possible and that it remain valid for a period of one year from the date of STC issuance. **International operations** The operators of U.S.

- registered aircraft with earlier LiveTV IFE designs installed routinely fl y to the Caribbean as wel l as North, Central and South America. The new Ka Band radome is expected to operate in the same regions. Therefore, in accordance with § 11.83 L ive TV requests this exemption apply to both domestic and international operations. As the State of Registry

fo r most of the aircraft on which the modification will be installed the FAA will continue to be responsible for the airworthiness and continued airworthiness of these aircraft wherever they operate. **Good Cause Exists to Issue the Exemption without Notice an d Comment**  LiveTV requests that the FAA issue the exemption without publication for comment in the Federal Register. Section 11.87 lists four factors considered b y the agency in deciding whether a petitioner has shown good cause for the FAA not to delay action on the petition. Those factors are set forth below in italics along with the company ’ s response in plain text: (a) Wh ether granting the petition would set a precedent: According to the FAA ’ s exemption data base, eight ex emptions have been granted to § 25. 571(e)(1). Additionally , the FAA has perm itted aircraft to operate for a limited period of time pending the installation of required modifications to address a compliance issue discovered late in the certification process. (b) Wh ether the relief requested is identical to exemptions previously granted: The relief requested in this petition is different from the other grants of exemption from § 25.571(e)(1) in which applicants requested an exemption to use 0.85 V c at 8,000 feet rather than V c from sea level to 8, 000 feet as the rule required at that time. (c) Wh ether delaying action would adversely affect LiveTV: Inlight of the importance of the Ka band project to L iveTV ’ s core busi ness, the rapidly changing techn ology

involved in this modification, the project ’ s advanced stage, and the disruptions to operators that have contracted for the Ka Band s ys tem, delaying action on the petition would adversely affect LiveTV. (d) Wh ether the petition was filed in a timely manner: The petition is timely

filed. LiveTV has had fre quent discussions on this subject with the Chicago and Atlanta ACOs and the Transport Airplane Directorate for the last several weeks. In light of the above considerations LiveTV submits that good cause exists not to delay action on this request. **Federal R egister**  **publication** The FAA has determined that good cause exists for waiving the requirement for Federal Register p ublication for public comment. While the request is not identical to previously granted requests,4

it will not set a precedent in the long term. The reason for the exemption petition is due to recent FAA clarification on the intent of the rule, and the fact that the affected STC is nearing completion. Since the FAA guidance has now been widely circulated, we do not expect there to be any need f

or exemption requests in the future, except on current projects that are in the final stages. In addition, the exemption request is limited to one year. Lastly , we agree that any delay in acting on this petition would be detrimental to LiveTV and that this petition was filed in a timely manner. **The FAA ’**  **s analysis**  The FAA recentl y became aware of the inconsistent application of the bird strike requirement of § 25.571(e)(1) to radomes installed on airplanes

. Section 25.571(e)(1) requires the bird strike asse ssment to be performed at V c at sea level or 0.85V c at 8,000 feet, whichever is more critical

. Some applicants had been limiting the speed at which bird strike is assessed to ‘ ty pical ’ operational speeds. By

limiting speed, an applicant could show that the airplane is alway s at a positive

- pitch attitude , and that the radome will alway s be effectively “shadowed” by

the crown of the forward fuselage

. The FAA recentl y reiterated to all applicants that the rule requires consideration up to the design speeds stated in the rule

. In support of its petition, LiveTV has presented a probability analy sis showing that a bird strike on the radome is extremely improbable. W e agree that the probability of a bird strike is low

. However, th e re quirement itself does not allow probability to be used to avoid assessment of the bird strike , and therefore, an exemption is necessary

. Limiting the exemption to one year does further diminish the safety risk. The term “likel y” in the rule qualifies the term “structural damage,” rather than bird impact s
. In FAA Policy

Memo PS

- ANM100

- 1993

- 00041, issued 9/1/1993, we provide guidance on the term “likely structural damage” in the contex t of uncontained engine failure: In responding to a commenter who thought the word “ likely” in the lead

- in of the proposed § 25.571(e) was not necessary , the FAA disagreed by saying that “ the word likely has a substantive probability connotation in this context.” The assumption is that the engine failure event will occur but there is some latitude in defining the location and extent of damage inflicted by the engine debris. P robability

cannot be applied to airspeed or to the probability of impact itself

, because both the impact and the airspeed (V c ) are stated directl y i n the rule. The applicant must assume the bird strike will occur at V c or 0.85 V c as stated in the rule, and then determine the likely structural damage that would result from that bird strike. In consideration of the above, the FAA concludes that granting this exemption will not adversel y affect safety . For the reasons stated earlier by the petitioner, the FAA concludes that granting this time

- limited exemption would be in the public interest. **The FAA ’**  **s decision** In consideration of the foregoing, I find that a grant of exemption is in the public interest. Therefore, pursuant to the authority contained in 49 U.S.C. 40113 and 44701, delegated to me by the Administrator, Li veTV is hereb y granted an exemption from 14 CFR 25.571(e)(1)

. The exemption is granted to the extent necessary to allow Li veTV to install Ka radomes on Airbus Model A321 airplanes

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This exemption terminates one year from the date it is granted , unless sooner superseded or rescinded

. On or p rior to that date, Li veTV must demonstrate full compliance to the bird

- strike requirements of § 25.5 71(e)(1) , or the affected STC becomes void. Issued in Renton Washington, on May 9, 2013

/s/

Jeff Duven Acting Manager, Transport Airplane Directorate Aircraft Certification Service