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StandardAero

U.S. Department of Transportation

Docket Operations

West Building, Room W12-140

1200 New Jersey Avenue, SE

Washington, D.C. 20590-0001

June 20, 2013

Re: Petition for Exemption, 14 CFR § 25.571(e)(1), FAA Project ST08231CH-T, Installation ofthe Aircell

Broadband Services (ABS) System with Ku Enhancements on a Boeing 757 Series Aircraft

In accordance with 14 CFR Part 11, StandardAero hereby petitions for an exemption from 14 CFR §

25.571 (e)(1) (Amendment 25-45) as it relates to the above referenced certification project. For the reasons

detailed below, Standard Aero requests an immediate exemption from this rule and that it remain valid for a

period of one year from the date of STC issuance. .

StandardAero has been contracted by Gogo, LLC to perform engineering and certification services on Gogo's

behalf. As such, some of the information contained in this letter is based on relevant data that has been

performed by or on behalf of Gogo's current Ku Supplemental Type Certificate (STC) programs or pertains to

the commercial impact as it would affect Gogo, LLC.

Safety and Public Interest

The petition would not adversely affect safety because of the extremely low probability of a bird strike as

summarized below. This radome and similar radome types are currently installed on following aircraft types:

Airbus: A319, A320, A330, A340

Boeing: BBJ, 737, 747, 767, 777

McDonnell Douglas: MD-87

This service experience further demonstrates an additional margin of safety. Moreover, the aircraft's frontal

fuselage shadows the Ku Band radome due to the aircraft's angle of attack during all but the most extreme

flight operations. Additionally, we have substantial service information from Delta Airlines that identifies 127

Airbus A330 and Boeing 767 Series Aircraft which have over 500,000 accumulated hours throughout 2012,

including over 30,000 hours below 10,000 feet, without any bird strikes to a radome, which is detailed below in

bird strike substantiation section of this document. Additionally, similar radome is in service with Live TV for

over 13 years and close to 10 million flight hours without a bird strike occurrinq.'

Radome Design

The design of the Ku Band radome is an aerodynamic 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 aircraft's normal

flight operations due to the aircraft's angle of attack (AOA). In addition to these physical characteristics the

radome incorporates engineering advances in composite materials and lessons learned based on previous

installations.

1 In the matter of the petition(s) of LlVETV for an exemption from §25.571(e)(1) of Title 14, Code of Federal Regulations,

Regulatory Docket Nos. FAA-2013-0336, FAA-2013-0338, FAA-2013-0372, FAA-2013-0373 (United States Department of

Transportation, Federal Aviation Administration May 9,2013).
StandardAero chose the radome design, its location on the aircraft and method of compliance for 14 CFR §

25.571(e)(1) 7 months ago. The current project, ST08231CH-T, was submitted on January 25, 2013. FAA

project ST08231CH-T requires successful completion of FAA project number SA08072CH-T.

Bird strike substantiation

In the final rule preamble for § 21.101 (the changed product rule) the FAA acknowledged the importance of

determining the certification basis for changed aeronautical products in a timely manner:

The type certificate applicant needs to know, early in a certification program, what the applicable

airworthiness standards will be in order to finalize the detailed design of its product and to enable the

applicant to make reasonable performance guarantees to its potential customers. (65 FR 36246, June

7,2000)

Completion of STC project #SA08072CH-T is required for the successful completion of the above referenced

project. The design data package for SA08072CH-T that was submitted to the FAA Chicago ACO included a

Bird Strike report. DER approval for this report was granted with a limitation of maximum speed of 250 knots

below 10,000 ft. per normal operating conditions. This limitation is in accordance with normal operating

procedures for Boeing 767-300 series aircraft. All approvals along with additional reports were provided to the

ACO on 02/05/13.

Chicago ACO approached Transport Airplane Directorate (TAD) to seek guidance regarding the limitation as

identified in the Designated Engineering Representative's (DER's) approval. Transport Airplane Directorate

clarified interpretation of the Issue Paper ruling from "normal flight envelope" to "normal design envelope."

In 2009, EASA commissioned a study to evaluate the effects of bird strikes in an effort to determine the

adequacy of the FAA's certification requirements for bird strikes.

In the report, it was found that 96% of all bird strikes (which were statistically 186 per million flight hours for

transport category aircraft) occur in the takeoff, climb, approach and landing phase. These are the phases of

flight that normally occur below 10,000, during which time all transport aircraft in the United States are

operationally restricted to airspeeds of 250 KIAS or less.

The same report found that only 9% of all Part 25 bird strikes resulted in damage (including engines) and only

0.3% of the strikes involved kinetic energy above the required certification values.

Below is the data provided by Delta Air Lines for their 2012 fleet:

AlCwl

APPROX.

AIRCRAFT

LARGE ACCUM.HOURS ACCUM.CYCLES

BIRD STRIKES EXPOSURE

TYPE

ANT.

(total/radome) TIME BELOW

10,000 FT

A330 32 143,353 18,105 35/0 7,242

767 95 391,632 57,067 176/0 22827

This is only one year's worth of data however the airline reports that they have never experienced a bird strike

on a top fuselage mounted radome. In addition to the Airbus A330 and Boeing 767, they operate significant

numbers of Boeing 737 and 757 aircraft with large antenna installations.

A review of the actual bird strike data provided by the airline shows that the overwhelming majority of bird

strikes occurred in the landing and rollout phase of flight. It further shows that damage to the fuselage and

wings is extremely rare. The data appears very consistent with the conclusions of the EASA study.
A teleconference was held between Gogo, FAA Chicago ACO and Transport Airplane Directorate on

02/11/13. FAA determined that additional substantiation was required to show compliance to 14 CFR §

25.571 (e)(1).

Based on recommendation from TAD, bird strike simulation analysis was performed by Gogo. Results showed

the following:

• Bird penetrates radome

• Brackets holding the antenna fail and antenna starts to move back, inside the radome

• Antenna comes to rest inside the radome after 100msec

• Antenna is contained inside the radome and does not depart the radome

This report was reviewed by TAD and the Chicago ACO. TAD asked that following be performed to

substantiate the analysis:

• Validation of model that was created for analysis through a physical test

• Impact Loads analysis, to see effects of ram air inside the radome

• Effect on aircraft structure

• Conclusion - bird strike testing must be conducted if radome is exposed during any phase of flight for

all aircraft weights and speeds up to and including cruise velocity, Vc

Since the meeting with TAD and ACO, Gogo has conducted a physical bird strike test and performed several

analysis. This additional analysis has been quite intensive and involved a substantial effort from Gogo, our

vendors for this project, as well as our airline partner, Delta Airlines. However, additional time is needed to

continue to evaluate and substantiate the Ku radome design for full 14 CFR § 25.571 (e)(1) compliance.

The results of the physical test conducted in accordance with FAA approved test plan on 04/19/13 showed

that the antenna did not detach from the aircraft structure and minimal damage was caused to the antenna.

This test plan is on file with the Chicago ACO and is not part of this letter because it contains proprietary and

confidential data. Test results can be provided separately if required.

International operations

The operators of U.S.-registered aircraft who have contracted with Gogo for the new ABS System with Ku

enhancements design installed routinely fly to Europe, Asia, etc. The Ku Band satellite system is expected to

operate in the same regions. Therefore, in accordance with 14 CFR § 11.83, Gogo requests this exemption

apply to both domestic and international operations.

As the State of Registry for 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.

Commercial Impact

Gogo is incurring significant material costs as a result of the delay in obtaining approval of satellite system

installation on Delta Air Lines Boeing 757 aircraft.

Good Cause Exists to Issue the Exemption without Notice and Comment

StandardAero requests that the FAA issue the exemption without publication for comment in the Federal

Register.

Section 14 CFR § 11.87 lists four factors considered by 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 bold

italics along with the company's response in plain text:

(a) Whether granting the petition would set a precedent:

According to the FAA's exemption data base, fourteen exemptions have been granted to 14 CFR §

25.571(e)(1). Additionally, the FAA has permitted 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) Whether the relief requested is identical to exemptions previously granted:

The relief requested in this petition is different from ten out of the 14 of the other grants of exemption from

14 CFR § 25.571 (e)(1) in which applicants requested an exemption to use 0.85 Vc at 8,000 feet rather

than Vc from sea level to 8,000 feet as the rule required at that time. The relief requested in this petition is

identical to the remaining four exemptions in which the applicant requested an immediate exemption to

the rule itself.

(c) Whether delaying action would adversely affect Gogo:

In light of the importance of the Ku band project to Gogo's core business, the rapidly changing technology

involved in this modification, the project's advanced stage, and the disruptions to operators that have

contracted for the Ku band system, delaying action on the petition would adversely affect Gogo

(d) Whether the petition was filed in a timely manner:

The petition is timely filed. Gogo has had frequent discussions on this subject with the Chicago ACO and

the Transport Airplane Directorate for the last several months.

In light of the above considerations StandardAero subrruts that good cause exists not to delay action on this

request.

Summary of Exemption Request

In accordance with 14 CFR § 11.81(f), Gogo offers the following summary suitable for publication in the

Federal Register in the event the FAA believes that good cause to waive publication has not been established.

StandardAero, Business Aviation Services LLC. petitions the FAA for an exemption from the discrete source

damage tolerance (i.e., bird strike) requirements of 14 CFR § 25.571(e)(1) for a period of one year based on

data that such a bird strike encounter is less than extremely improbable.

Please feel free to contact me if you need further information.

Respectfully,

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Tim Winiesdorffer

ODA administrator

StandardAero

1200 North Airport Drive

Springfield, IL 62707

United States

Mobile: 614.402.4455

Tim. Win iesdorffer@standardaero.com

www.standardaero.com