March 3 , 2015

U.S. Department of Transportation Docket Operations West Building Ground Floor, Room W12

- 140 1200 New Jersey Avenue, SE Washington, DC 20590

Subject: Petition for Exemption

Reference: 14 CFR §121.629(b)

– Operation in Icing Conditions

Dear Sir or Madam:

In accordance with the provisions of Title 14, Code of Federal Regulations (14 CFR) §11.63 and §11.81, Airlines for America, on behalf of our passenger and cargo airline members and similarly

situated air c arriers 1 , petitions for a limited Exemption from 14 CFR §121.629(b). Specifically, A4A requests an Exemption on the Boeing B737

- 600,

- 700,

- 800 and

- 900 /

- 900ER “ Nex t Generation ” ( B737NG ) series aircraft from the requirement that “No person may take off an aircraft when frost, ice, or snow is adhering to the wings” where the Original Equipment Manufacturer (OEM) has determined a “safe” zone within which cold soaked fuel frost (CSFF) is permissible, has visibly marked the zone on the wing, and has placed an appropriate limitation in the Airplane Flight Manual (AFM) that the Federal Aviation Administration has approved.

Background

Airframe icing in general has long been known to be a hazard to safe operation of aircraft, especially on the wing. Wing surface texture changes can disrupt laminar airflow on the wing causing loss of lift and reduced stall speed, adversely affecting aircraft performance. Further, the weight of accumulated ice may present a weight and balance issue unknown to the crew and that cannot be accurately estimated from visual observation. Ice on the wing may form in a particular set of conditions that may include near

- or sub

- freezing temperatures in combination with precipitation and/or high humidity (especially fog). Ad ditionally, frost may form on a cold wing, particularly in areas with underlying cold soaked fuel as in the case of an airplane recently exposed to high altitude cruise conditions that has landed in a humid climate, a condition known

as CSFF.

Boeing has applied painted lines defining an area on the upper surface of the wings on certain

B 737 NG aircraft where, with certain other li mitations, CSFF may exist with negligible impairment of performance. Boeing has i ssued a new limitation in the AFM that sets forth conditions under which takeoff is not permitted with CSFF (attachmen t 1), stating that CSFF outside the painted

limit lines, extremely cold fuel, or t he presence of other common airframe icing conditions preclude takeoff in accordance with 14 CFR §121.629(b). However, if the above

- listed limiting

1 A4A airline members affected by the issue are: Alaska Airlines, Inc.; American Airlines, Inc.; Delta Air Lines, Inc.; Southwest
Airlines Co.; and United Air Lines, Inc.March 3, 2015, A4A Petition for Exemption

conditions are not met, i.e. CSFF is present within the limit lines and other specified adverse conditions do not exist, operation should be permissible. An examp le of such permissible operation would be an airplane that has arrived in a moderate t emperature, humid climate after long

- range high altitude cruise. Frost may form in the limited area due to cold fuel, but the outside

conditions are not otherwise conduci ve to icing and Boeing’s limitation would not preclude takeoff.

Regulation 14 CFR 121.629 does not allow for any exception, including the OEM’s safety determination set forth in the Airplane Flight Manual, an FAA approved document. By approving
the AFM, FAA provides the basis upon which operation with CSFF can be permitted if this petition is granted.

The Applicable Regulations and Relief Sought

We seek an exemption from 14 CFR §121.629(b) to permit operation with CSFF within a defined area of the wing ’s upper surface The exemption would be limited by Boeing’s Airplane Flight

Manual

– Miscellaneous Limitations notation that defines conditions under which takeoff with CSFF is not permitted.

Reasons for seeking the relief at this time include:

1) FAA has approved Boeing’s conservative determination through aerodynamic analysis of the conditions under which operation wi th CSFF is and is not permitted. 2) Boeing’s application of painted lines on the wing, which FAA also approved, define the areas

of acceptable CSFF. 3) The AFM limitation assures that operations are only permitted in certain instances of cold soaked fuel, operations are not authorized (without deicing) when airframe icing conditions

otherwise exist.

Granting the Exemption Would Not Adversely Affect Safety

Safety will not be adversely impacted if the FAA grants this petition because FAA has concluded by approving the AFM that the conditions under which operation with CS FF present is permitted

on B737NG by the AFM are sufficientl y conservative and tested by Boeing to be safe for takeoff.

The requirements contained in this AFM limitation prevent application on aircraft that are not eligible. A visual inspection of the upper wing surface is required t o ensure that CSFF is not beyond the lines defining the boundaries of the cold soaked fuel frost a re a. To apply the revised

B737 NG AFM limitation for Cold Soaked Fuel Frost, the B737

- NG must have the “permissible” lines defining the boundaries of the CSFF ar ea on the upper wing. The B737 NG AFM limitation for CSFF cannot be applied to a 737 Classic ( 100

- 500) series aircraft or B 737 NG aircraft that has

not been delivered or later modified with the CSFF boundary lines.March 3, 2015, A4A Petition for Exemption

A Summary of this Petition that FAA Could Publish in the Federal Register

Petitioner: Airlines for America Affected Regulations: 14 CFR 121.629(b) Summary of Relief Sought: FAA is requested to provide relief from the cited rule when the OEM, Boeing allows operation of B737

- 600,

- 700,

- 800, and

- 900 /

- 900ER

“ NG ” ai rcraft with Cold Soaked Fuel Frost present in defined areas of the wing upper surface and states conditions in the FAA

- approved Airplane Flight Manual when operations are not permitted.

Granting this Exemption is in the public interest as it maintains an equivalent level of safety, because Boeing has conducted aerodynamic analyses that conservatively conclude the conditions under which safe operation is permissible.

Conclusion

For the foregoing reasons, we respectfully request an Exemption from the requi rements of 14 CFR §121.629(b) for CSFF limited by Boeing’s AFM conditions.

Sincerely,

Robert Ireland Managing Director Engineering and MaintenanceMarch 3, 2015, A4A Petition for Exemption

ATTACHMENT 1

– Excerpt from Boeing B737NG Airplane Flight Manual