AFS-13-142-E

Exemption No. 10818

UNITED STATES OF AMERICA

DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

WASHINGTON, DC 20591

 

In the matter of the petition of 

 

DELTA AIR LINES, INC. Regulatory Docket No. FAA-2012-1349

for an exemption from § 91.9(a)

of Title 14, Code of 

Federal Regulations 

 

GRANT OF EXEMPTION

 By letter dated December 21, 2012, Mr. Stephen M. Dickson, Senior Vice President Flight 

Operations, Delta Air Lines, Inc. (Delta), 1030 Delta Boulevard, Department 207, Atlanta, 

Georgia 30320 petitioned the Federal Aviation Administration (FAA) for an exemption from 

§ 91.9(a) of Title 14, Code of Federal Regulations (14 CFR). This exemption, if granted, 

would allow a select group of Delta Senior Line Check Airman Pilots to operate Apple iPads 

on the flight deck under certain conditions and limitations for the purpose of conducting 

research into turbulence mitigation and avoidance.

The petitioner requests relief from the following regulation:

Section 91.9(a) prescribes, in pertinent part that 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. 

The petitioner supports its request with the following information:

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. in-flight injuries). “Turbulence encounters accounted for more 

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

initiated a research project in an attempt to mitigate this statistic.

Delta is requesting an exemption from §91.9(a) to perform a demonstration, with the 

cooperation of the FAA's Aviation Weather Research Program Turbulence Product Development 

Team (TPDT), the feasibility of using a low-cost tablet personal computer (PC), specifically an 

Apple iPad (WiFi only; no cellular transmission-capable units), for the displaying of Graphical 

Turbulence Guidance (GTG) and Eddy Dissipation Rate (EDR) information in the cockpit for use 

by the flight crew. EDR is aircraft sensor derived and auto-reported at a much greater frequency 

than Pilot Reports (PIREPs). PIREPs are subjective in nature, and may be geographically 

inaccurate. Turbulence severity and location reported via PIREPs are often reported in a general, 

conservative sense, resulting in reallocation of airspace or pilots avoiding large areas of airspace 

that may not actually be experiencing turbulence conditions. Delta previously participated in the 

adaptation, testing, and deployment of the EDR algorithm on its aircraft and completed 

installation of the EDR algorithm on its Delta B737-800 fleet in September 2008.

In April 2009, following the initial EDR installation, the FAA funded an effort to assess the 

safety, efficiency, and capacity benefits of providing improved GTG and EDR information to 

flight planners and dispatchers. That effort was to determine how EDR data might help in 

achieving increased airspace capacity through its use by pilots, dispatchers, and Air Traffic 

Control (ATC) in minimizing deviations in areas of turbulence. Currently, the GTG and EDR 

information are provided to the dispatchers via a dedicated viewer. The dispatchers utilize the 

information to coordinate the optimized altitudes and tracks with the pilots and ATC. The result 

is fewer unnecessary altitude changes and a reduction in workload for both pilots and controllers. 

The EDR Proof-of-Concept Demonstration effort was completed in January of 2011. 

This new joint effort will be conducted to demonstrate the ability and capability for transmitting 

GTG and EDR information directly to the flight crews and to identify any benefits resulting from 

decision making through early turbulence warning. 

Delta states the B737 is the only aircraft type within its fleet that has both WiFi and the new 

turbulence reporting algorithm. Therefore, these are the only aircraft in the Delta fleet suitable 

for this test program. The Delta B737-800 aircraft to be used during the research effort are 

equipped with GoGo WiFi service that was installed on the aircraft via Supplemental Type 

Certificate (STC) ST02541CH (Installation of Aircell Broadband Services (ABS) System). 

The aircraft are also equipped with Honeywell “Phase 3” Display Units. The following 

textual excerpt was taken from the Additional conditions and limitations 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 Effective 

Isotropic Radiated Power (EIRP) Personal Electronic Devices (PEDs) wireless emission tests. 
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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.” 

In lay terms, certain WiFi devices used on the flight deck can cause interference with the 

Phase 3 displays. Therefore, a placard to prohibit the use of WiFi devices on the flight deck 

when engines are operating for the purposes of flight has been installed in all Delta B737-800 

aircraft to ensure compliance. Relief from §91.9(a) (which mandates aircraft must be 

operated compliant with the operating limitations of, among other things, placards) would 

permit Delta Senior Line Check Airmen (LCA) pilots on the test aircraft to use a WiFienabled Apple iPad on the flight deck.

Delta is requesting relief for 40 Delta B737 Senior LCA pilots to access a web-based enroute 

turbulence tool using the existing aircraft WiFi connection. The exemption would 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. 

In a similar demonstration, Boeing performed Electro-Magnetic Interference/Radio Frequency 

Interference (EMI/RFI) tests of the Honeywell Phase 3 Display Units (DU) and developed 

recommended distances from the DUs for safe use of wireless radiating devices. At a 

measured transmitter output of 100 mw, the safe distance determined by Boeing’s test is no 

closer than 7 inches from the DU.

The Apple iPad to be used for this project has an Effective Radiated Power of approximately 

40 milliwatts (mW). The normal radiated power of the iPad is approximately 100 times less 

than the 4 watt value identified to cause the display unit anomaly during STC testing. The 

manufacturer of the tablet does state the possibility of spike wattage of 0.35 watts (350 mW), 

which is still far below the 4 watt threshold identified during STC testing. Per Boeing’s 

testing and calculations, at the normal output power of the Apple iPad (40mW), no 

interference with the DUs will occur if the device is kept at least 4 inches or more away from 

the DU. Delta validated Boeing’s testing by operating the iPad at the recommended distance

from the display while on the ground. Delta reports no display anomalies when placing the 

iPad as close as 1 inch from the display.

Delta states that, modification or replacement of the Phase 3 displays is impractical. It states

that, because of the number of Phase 3 DUs in service and Honeywell’s limited ability to 

update the existing units, the process of replacement could take two to three years. In addition, 

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

Delta further states that a level of safety at least equal to that provided by the rule is achieved 

by the following:
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1. Use of the iPads will be limited to approximately 40 Line Check Airman pilots who 

have been properly trained in use of the device as well as the conditions and 

limitations placed upon use of the device on the flight deck;

2. 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 LCA;

3. Procedures will be in place to ensure that the LCA disable the Bluetooth capability of 

the iPad before use in-flight;

4. Use of the iPad on the flight deck will be limited to one device used at either the pilot 

or first officer’s position (not both) on any given flight;

5. Use of the iPad on the flight deck will only occur during non-critical stages of flight, 

and the devices will be powered off and stowed below 10,000 feet;

6. The iPad will not be used forward of the control column, thus maintaining a distance 

of at least 18 inches from the Phase 3 DU; and

7. If any DU anomalies occur, the iPad will immediately be turned off and stowed for the 

duration of the flight.

 A summary of the petition was published in the Federal Register on January 18, 2013 

(78 FR 4190). No comments were received.

Additionally, Delta states this will be a benefit to the public because the planned research will 

examine the impacts of providing aircrews with atmospheric turbulence information prior to

an actual turbulence encounter. This collection of data will help to increase situational 

awareness of the air cre members. Provisioning of better turbulence information on the flight

deck 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 

flight crews can better coordinate with controllers regarding flight altitudes, and flight crews 

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 National Airspace System benefits based on lessons learned from the 

data collected. Since this capability can be transferred to all aircraft, all segments of aviation 

will benefit. 

The FAA's analysis is as follows:

The FAA has reviewed the methods and results of Boeing’s EMI/RFI testing of the Honeywell 

Phase 3 DU and finds that the combination of low transmit power (40 to 350mw) of the Apple 

iPad operating in a WiFi-only mode, combined with operational controls listed in the 

conditions and limitations section below provides a level of safety equivalent to that provided 
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by prohibiting use of WiFi devices on the flight deck. Testing conducted by Boeing has 

outlined safe radiated power/distance criteria that Delta’s operational procedures will surpass. 

Among the conditions and limitations listed below is a requirement to operate the iPad no 

closer than 18 inches from the DUs. This distance is more than quadruple the safe distance 

identified by Boeing’s testing. The operational controls combined with instrument panel 

layout ensure that interference with more than one display is very highly unlikely. Delta has 

outlined procedures to mitigate DU interference in the unlikely event it occurs. The FAA 

concurs that the mitigation procedures are effective, and will not jeopardize safe operation of 

the aircraft.

The FAA further finds that Delta has sufficiently illustrated how granting of this petition is in 

the public’s 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, Delta Air Lines, Inc. is granted an exemption from 14 CFR § 91.9(a)

to the extent necessary to allow certain Delta Line Check Airman pilots to operate Apple iPad 

WiFi-only devices on the flight deck for the purpose of conducting turbulence mitigation and 

avoidance research, subject to the conditions and limitations listed below.

Conditions and Limitations

1. Delta must adhere to the following operational controls and include them in any 

instructions, processes and procedures provided to the participating LCA pilots:

a. Use of the iPad is limited to non-critical stages of flight. The iPad will be powered 

off and stowed below 10,000 feet;

b. No more than one iPad may be used, and must be used in either the Pilot’s or First 

Officer’s position (not both) on any given flight;

c. LCAs will ensure Bluetooth functionality is disabled on the iPad prior to flight;

d. The iPad will not be used forward of the control column at any time during flight. 

This will ensure a separation of at least 18 inches between the iPad and DUs; and

e. If any DU anomalies occur, the iPad will immediately be powered off and stowed 

for the duration of the flight.

2. Prior to start of the research program, Delta shall provide the names of the LCA pilots 

who will participate in the program and the date(s) each pilot was trained on the 

operational controls to the Delta Certificate Management Office (CMO). Only those 

LCA identified and trained shall participate.

3. This exemption applies only to use of Apple iPad Wifi-only devices during turbulence 

mitigation and avoidance research. No other WiFi devices shall be used on the flight 

deck of placarded B737NG aircraft, nor shall the iPad be used during flight for any 
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other purpose. Further, this relief does not extend to any other placard or marking 

beyond the flight deck placard with reads “USE OF WI-FI DEVICES ON THE 

FLIGHT DECK PROHIBITED WHEN ENGINES OPERATING FOR PURPOSE OF 

FLIGHT.”

This exemption terminates on October 31, 2014, unless sooner superseded or rescinded.

Issued in Washington, DC, on July 8, 2013 .

/s/

John M. Allen

Director, Flight Standards

 Service