BEFORE THE

FEDERAL AVIATION ADMINISTRATION

WASHINGTON D.C.

 Docket FAA-2012-

PETITION OF DELTA AIR LINES, INC.

FOR AN EXEMPTION

December 21, 2012

Delta Air Lines, Incorporated, operating certificate DALA026A, hereby petitions the Federal 

Aviation Administration (FAA), pursuant to 14 C.F.R. Part 11 for partial relief from Federal 

Aviation Regulation (FAR) §91.9(a), provided certain conditions and limitations are met. 

Section of the FAR Affected:

Section §91.9(a), Civil aircraft flight manual, marking, and placard requirements, states in 

pertinent part:

“(a) Except as provided in paragraph (d) of this section, no person may operate a civil 

aircraft without complying with the operating limitations specified in the approved Airplane 

or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the 

certificating authority of the country of registry.”

Background:

The National Transportation Safety Board (NTSB) determined that between 2007 and 2009, 

turbulence encounters during the en route phase of flight continues to be the most common 

cause of Part 121 accidents (i.e. inflight injuries). “Turbulence encounters accounted for 

more than one-third of the accident events, and all but one of the 32 encounters with 

turbulence occurred during en route phases of flight. Most of these accidents (29 of 32) 

resulted in serious injury to a single passenger or cabin crew member, but in one case two 

persons were seriously injured and in another case six persons were seriously injured. 

Minor aircraft damage was reported in 2 of the 32 turbulence accidents.” Therefore, the 

FAA and Delta Air Lines (DAL) have initiated a research project in an attempt to mitigate 

this statistic. However, in order to conduct the research, it will be necessary to access a 

web-based turbulence tool using the aircraft WiFi during non-critical phases of flight. 

Unfortunately, the 4 watt Electro-Magnetic Interference / Radio Frequency Interference 

(EMI/RFI) testing of the Boeing 737NG cockpit electronics has identified a potential safety 

Petition of:

DELTA AIR LINES, INC.

OPERATING CERTIFICATE DALA026A

For exemption of certain requirements of 

14 C.F.R. §91.9(a)
Petition for Exemption - (FAR) §91.9(a)

Delta Air Lines, Inc.

December 21, 2012

Page 2

risk to the Honeywell “Phase 3” Display Unit (DU), P/N 4091900-xxx, by the onboard GoGo 

WiFi service; which has resulted in a Supplemental Type Certificate (STC) being issued 

against the GoGo WiFi link. Therefore, a placard to prohibit the use of Wi-Fi devices on the 

flight deck when engines are operating for the purposes of flight has been installed in all 

B737-700/800 aircraft to ensure compliance. 

The following textual excerpt was taken from the Additional Limitations and Conditions 

section of the FAA Approved Model List of ST02541CH:

“Honeywell Display Unit (DU), P/N 4091900-xxx (Example P/Ns 4091900-931, 

4091900-932, 4091900-933 and 4091900-934), exhibited susceptibility during 4 

watt EIRP Personal Electronic Devices (PEDs) wireless emission tests. Installation of 

the Aircell ABS on aircraft with these displays requires prohibition of use of Wi-Fi 

devices on the flight deck when engines are operating for the purposes of flight.”

Therefore, a placard to prohibit the use of Wi-Fi devices on the flight deck when engines are 

operating for the purposes of flight has been installed in all B737-700/800 aircraft to ensure 

compliance. The placard wording is as follows: 

“USE OF WI-FI DEVICES ON THE FLIGHT DECK PROHIBITED WHEN ENGINES 

OPERATING FOR PURPOSE OF FLIGHT”

Extent of Relief and Reason

In order to proceed with the research effort, DAL is seeking a Petition for Exemption from 

CFR Title 14, Part 91.9(a), as it relates to the placard on the flight deck associated with a 

Supplemental Type Certificate (ST02541CH) issued to Gogo LLC. 

DAL is requesting relief for 40 Delta B737 Senior Line Check Airmen (LCA) pilots to access a 

web-based enroute turbulence tool using the existing aircraft WiFi connection. The 

Exemption would only be required during the operational demonstration period of the 

research effort; anticipated to last approximately 1 year, and only during non-critical phases 

of flight. The device to be used to access this web-based turbulence information will be an 

Apple iPad with a known radiating power and frequency.

The tablet PCs under consideration for this project WiFi connection has an Effective Radiated 

Power of approximately 40 milliwatts (mw); far below those powers and frequencies that 

prompted the STC The subject STC states that the display units only “exhibited 

susceptibility during 4 watt EIRP Personal Electronic Devices (PEDs) wireless emission 

tests”. The normal radiating power of the proposed demonstration tablet PC is 

approximately 100 times less than the value identified to cause the display unit anomaly. 

The manufacturer of the tablet’s transmitting device does state the possibility of spike 

wattage of 350 mw which equates to only 0.35 watts. 

Boeing performed testing of Electro-Magnetic Interference / Radio Frequency Interference 

and developed recommended distances from the display units to mitigate the potential 

flickering or blanking issue. At 100 mw, the distance is no closer than 7 inches. Delta has 

validated Boeing’s testing by taking the proposed devises and operating them at the 

recommended distances from the display while on the ground. There have been no display 
Petition for Exemption - (FAR) §91.9(a)

Delta Air Lines, Inc.

December 21, 2012

Page 3

issues even when placing the device within 1 inch of the display. However, to account for 

the possible spike in wattage, Delta will maintain a distance of 18 inches from the display 

units while in flight. This is easily trained and recognizable by not bringing the devices 

forward of the control column. 

The B737 is the only aircraft type within DAL’s fleet that has both WiFi and the new 

turbulence reporting algorithm. Because of the number of DU’s in service and Honeywell’s 

ability to update the existing units, the process of replacement could take two to three 

years. This would delay benefits to the public and potentially impact the schedule for the 

weather integration in the NextGen planning cycle. NextGen has been identified as being 

critical to our nation’s infrastructure and its schedule is critical to the benefits anticipated 

from a timely implementation.

Request for expedited consideration: 

DAL is also requesting that, as part of this Petition for Exemption request, the public 

comment phase be waived as per Title 14 CFR Part 11.87(a) and (c), which states:

“The FAA may not publish a summary of your petition for exemption and request 

comments if you present or we find good cause why we should not delay action on your 

petition. The factors we consider in deciding not to request comment include:.

(a) Whether granting your petition would set a precedent... 

(c) Whether our delaying action on your petition would affect you adversely.”

It is the opinion of DAL that since the mitigating actions remove the operational threat, 

there is no precedent being set with our request. The purpose of this Petition is limited to 

40 highly skilled and trained Line Check Airmen (LCA) for a one year period with significant 

procedures in place to mitigate any safety issues.

It is also the opinion of DAL that any additional delay in the commencement of these 

operational demonstrations would result in a delay in providing enhanced turbulence 

information to the cockpit that may ultimately reduce injuries to the traveling public. 

Turbulence is the leading cause of inflight injuries in commercial aviation. Pilots currently 

have limited turbulence information at their disposal during flight. Their information is 

limited to either their preflight information briefing material or the information they receive 

via the ATC frequency. The intent of this research is to provide near real-time turbulence 

information to the cockpit to enable the pilot to make proactive decisions prior to entering 

into a turbulence environment. These proactive decisions would enhance aviation safety 

in/around areas of inflight turbulence.

Planned Research 

The FAA Aviation Weather Division (AWD) teamed with DAL in a research effort to attempt 

to increase safety within the National Airspace System (NAS) by reducing passenger and 

cabin crew injuries due to unexpected turbulence encounters. Initial research with the FAA 

and DAL demonstrated that providing enroute turbulence information to dispatchers
Petition for Exemption - (FAR) §91.9(a)

Delta Air Lines, Inc.

December 21, 2012

Page 4

improved safety, fewer capacity constraints, and lower aircraft emissions. This new phase 

of research would provide the same information to flightcrews as is currently being provided 

to the dispatchers at DAL. Safety would be enhanced through improved knowledge of 

turbulence events to the flightcrews.

The proposed research effort will quantify the benefits of providing enhanced turbulence 

forecast and near real-time aircraft derived turbulence reports on the operation of the 

aircraft. The LCA, through the use of the tablet iPad device and the onboard WiFi 

connection, will be able to access and display turbulence information during non-critical 

phases of flight. An enhanced turbulence forecast model updated every hour will be made 

available to the crew in real time. This observed turbulence information will provide the 

flightcrew with temporally and spatially relevant turbulence information that is currently 

unavailable to the cockpit. Having this information at their disposal will allow the flightcrew 

to better manage their flight while reducing cockpit workload. It is anticipated that access 

to enhanced turbulence information will result in better flight management, cabin 

management and overall safety of the operation. 

Public Benefit

The most significant impact resulting from inflight turbulence encounters during commercial 

operations is injury to the passengers and cabin crew. The planned research will examine 

the impacts of providing aircrews with atmospheric turbulence information prior to an actual 

turbulence encounter; thus increasing their situational awareness. Provisioning of better 

turbulence information on the flightdeck could lead to improved mitigation or avoidance 

procedures resulting in far fewer cabin injuries to passengers and cabin crew members. 

With improved turbulence knowledge, the flightcrews can better coordinate with controllers 

regarding flight altitudes and flightcrews can better coordinate with their cabin crews to 

provide advance warning of upcoming areas of turbulence. 

Delta’s expectation is the program will enhance the experience of the traveling public which 

will benefit the total air transportation system. The demonstration will provide the FAA 

important information on how to validate the improvements in the system and quantify 

operational and NAS benefits based on lessons learned from the data collected. Since this 

capability can be transferred to all aircraft, all segments of aviation will benefit.

No Adverse Affect on Safety:

DAL is seeking to allow 40 DAL B737 senior LCA pilots to use Apple iPad device Wi-Fi 

connection to access a web-based enroute turbulence product on the B737-700/800 flight 

deck during non-critical phases of flight. 

The web-based turbulence information is derived from an objective onboard turbulence 

reporting system and advanced forecast tool developed by the FAA NextGen New Weather 

Concept Development Branch of the Aviation Weather Division in conjunction with the 

National Center for Atmospheric Research (NCAR). The demonstration is scheduled to last

one year. A well-defined and approved risk mitigation strategy will be in place during the 

research demonstration. Delta will put in a place a risk mitigation strategy that includes the 

following as a minimum.
Petition for Exemption - (FAR) §91.9(a)

Delta Air Lines, Inc.

December 21, 2012

Page 5

 Human in the Loop (HITL) evaluations in a B737NG simulator will be conducted in 

advance of the operational demonstrations to develop operational procedures and 

training for the line check airmen. These HITL evaluations will be coordinated with 

FAA Flight Standards.

 DAL will provide 40 of their LCA with Apple WiFi-only iPad devices. Procedures will 

be in place to ensure that the LCA pilots disable the Bluetooth capability on their 

device.

 Procedures will dictate that there will be only one iPad device in use on the flightdeck 

during any demonstration flight.

 Use of the iPad device will be restricted to only one side of the cockpit (Captain or 

First Officer) during any demonstration flight.

 The iPad device will be kept a minimum of 18 inches from any display unit. 

 If any display unit blanking or blinking occurs, use of the iPad device will 

immediately be terminated and the iPad device will be powered off and stowed. 

 The iPad device will not be used during critical phases of flight and will be powered 

off and stowed below 10,000 feet.

DAL conducted an internal Safety Review Analysis of this research project as part of their 

FAA approved Safety Management System (SMS) program. Based upon information 

obtained from Boeing, the FAA, Gogo, and Delta’s technical operations’ group, DAL’s 

internal Safety Analysis concluded that, with the risk mitigation plan in place during the 

operational demonstration, there is no risk to the aircraft, the crew, or the passengers (See 

attached Delta SRMD)

Given the importance of using the B737NG aircraft in this demonstration, based upon an 

October 15th discussion between DAL and Boeing, DAL requested a No Technical Objection 

(NTO) from Boeing. On October 24, 2012, Boeing responded to DAL’s request with the 

following statement: “Boeing engineering has No Technical Objection (NTO) to Delta's 

proposed plan of action...” (See attached NTO)

Summary for Federal Register

 Rule from which you seek the exemption

o DAL is petitioning for a one year exemption from CFR Title 14, Part 91.9(a), as it 

relates to the placard on the flight deck associated with a Supplemental Type 

Certificate (ST02541CH) issued to Gogo LLC.

 Brief description of the exemption 

o The current placard on the B737NG flight deck prohibits the use of WiFi while the 

engines are operating for the purpose of flight. 14 CFR Part 91.9(a) requires 

compliance with all aircraft markings and placards. In order to assess the safety 

benefit of providing enhanced inflight turbulence information to the pilot, DAL is 

requesting relief for 40 Delta B737 Senior Line Check Airmen (LCA) pilots to 

access a web-based enroute turbulence tool during non-critical phases of flight 

using the existing aircraft WiFi connection. The LCA will be using a low wattage 

WiFi-only iPad device. The exemption would be necessary for a period of 

approximately 1 year during the operational demonstration phase of effort.
Petition for Exemption - (FAR) §91.9(a)

Delta Air Lines, Inc.

December 21, 2012

Page 6

Please contact Charles M. Schramek, General Manager Quality Assurance and Compliance, 

at (404) 715-1112 or e-mail at chuck.schramek@delta.com, if you have and questions or 

need additional information.

Sincerely,

Stephen M. Dickson

Senior Vice President Flight Operations

Delta Air Lines, Inc.

cc: Steve Gorman, Chief Operating Officer – Delta Air Lines

Ken Hylander, Senior Vice President Corporate Safety, Security, and Compliance – Delta Air Lines

Lisa Brockenbrough, Director, Flight Safety – Delta Air Lines

Charles M. Schramek, General Manager Quality Assurance and Compliance – Delta Air Lines

Thomas Stachiw, Office Manager Delta Certificate Office – FAA

James T. Giles, Jr, Principal Operations Inspector Delta Certificate Management Unit – FAA

Attachments: Delta SRMD

Boeing NTO