1022 Airport Parkway ♦ Cheyenne, WY 82001 ♦ (307) 432-7210 ♦ Fax (307) 432-7001

Great Lakes Airlines

PETITION FOR EXEMPTION: 14 CFR 135.223

Section Great Lakes Aviation, Ltd. is seeking exemption from:

FAR Part 135.223

EXTENT AND REASON FOR RELIEF

Great Lakes Aviation, Ltd. petitions the administrator for relief from the alternate weather 

requirements set forth in FAR 135.223 and to instead use the alternate weather requirements of

FAR 121.619 for all domestic operations. 

Great Lakes Aviation’s Operation Specifications allow us to operate our Beech 1900D’s under 

FAR 121 and 135. Great Lakes utilizes the more restrictive guidance provided in FAR 121 for 

both operations (operations, maintenance, training, dispatching, etc.) in order to enhance safety 

for the flying public, as well as maintain a consistency between the two operations.

Our proposal would change the method for determining whether an alternate is required by 

utilizing one (1) set of rules (FAR 121.619) for our entire operation in lieu of utilizing two (2)

different sets of rules (FAR 121.619 and FAR 135.223). This allowance would be contingent 

upon dispatching and tracking all flights (121 and 135) in accordance with FAR 121 Subpart U,

using a Great Lakes approved dispatcher.
1022 Airport Parkway ♦ Cheyenne, WY 82001 ♦ (307) 432-7210 ♦ Fax (307) 432-7001

Explanation of 135.223 and 121.619:

FAR 135.223 “IFR: Alternate Weather Requirements” is slightly more restrictive in nature than 

its 121 counterpart, FAR 121.619. Below are the criteria to determine if an alternate will be 

required using FAR 135.223:

CEILING

o Add 1500 feet to the lowest circling approach for the destination airport; or if no 

circling approach exists:

o Add 1500 feet to the lowest approach minimums for the destination airport; or 

2000 feet, whichever is higher.

VISIBILITY

o 3 miles; or

o 2 miles more than the approach visibility requirements for the approach intended 

for use, whichever is higher

If the weather is below the above requirements at the destination airport, an alternate is 

required.

FAR 121.619 states that an alternate is required unless the weather at the destination is at 

least:

CEILING

o 2000 feet and;

VISIBILITY

o 3 miles

In accordance with Great Lakes’ Operations Specifications, Great Lakes is required to dispatch

all flights (121 and 135) under the more restrictive FAR 121 subpart U. Great Lakes has chosen

this requirement for our operation to maintain the additional safety margins for flight crews, 

passengers, as well as to the overall operation.

A Great Lakes Aviation, Ltd. flight operated under 121 or 135 is under constant surveillance by 

a dispatcher, as well as provided continuous communication capabilities with our dispatch 

center located in Cheyenne, WY. Company dispatchers provide each Pilot in Command

continuous updates on the weather at their destination and alternates, NOTAMS, etc. In 

addition, Great Lakes Aviation provides each Pilot in Command / Dispatcher a means to directly 

communicate with each other by use of AIRINC, and/or company radio. A flight can be in 

contact with the company anywhere throughout our route structure at any time. 
1022 Airport Parkway ♦ Cheyenne, WY 82001 ♦ (307) 432-7210 ♦ Fax (307) 432-7001

JUSTIFICATION FOR REQUEST

FAR 135.223 and FAR 121.619 both provide similar requirements for air carriers to determine if 

an alternate is required for a flight. These regulations assume that there will be an adequate 

level of margin between the weather requirements of these rules and the minimums imposed for 

that instrument approach procedure available at that airport. 

Depending upon the minimums associated with that approach, if relief is granted from 135.223 

and the alternate weather requirements of 121.619 are allowed to be used for both operations, 

there would always be an adequate weather margin between the alternate weather requirement 

and instrument approach minimums. In many cases, this margin will be in upwards of 1800 feet 

and 2 1⁄2 sm visibility if using a precision approach, and as low as 1000 feet and 1sm visibility if 

using a non-precision approach. With a dispatcher continuously monitoring each flight, any 

weather changes that would reduce these margins to a point where it may affect the ability of 

the crew to land can be communicated to the Pilot in Command. This can be done prior to

reaching that airport and any changes needed to be made to the flight plan can be done without 

undue delay. These procedures are already set in place in our standard operating procedures, 

and have been utilized in this manner since Great Lakes became an FAR 121 air carrier many 

years ago. 

It is assumed that FAR 135.223 is more restrictive in nature due to the limited requirements for 

dispatchers for carriers that operate under FAR 135. As a result of the limited regulations 

requiring dispatchers under 135, it is possible that an increased weather margin would be 

needed to add an additional margin of safety for the Pilot in Command in the event unforecasted weather should prevent the arrival at that airport, especially if that Pilot in Command 

is not provided continuous updated weather from a dispatch center. 

It is under these pretenses that Great Lakes Aviation requests the ability to utilize FAR 121.619 

for determining alternate weather requirements. The following would be requirements imposed 

on Great Lakes Aviation, Ltd. to utilize such an exemption:

1) All FAR 135 flights are to be dispatched and under continuous surveillance by a Great 

Lakes Aviation dispatcher, trained in accordance with Great Lakes’ approved Dispatcher 

program.

2) All FAR 135 flights will be dispatched in accordance with FAR 121 Subpart U.

3) Each dispatcher will be provided a system to display the location of each flight and 

current/significant weather. 

4) The dispatch system will have a system to alert the dispatcher when there is a change to 

a weather forecast, METAR, or a special weather update. 

5) Great Lakes Aviation will provide a means of communication to allow all flight crews and 

dispatchers continuous communication ability for weather changes, dispatch release 

changes, etc. throughout Great Lakes’ route structure.

6) This relief will only applicable to airports within the 48 contiguous United States and the 

District of Columbia.
1022 Airport Parkway ♦ Cheyenne, WY 82001 ♦ (307) 432-7210 ♦ Fax (307) 432-7001

PUBLIC SAFETY

Public safety would not be affected while utilizing FAR 121.619 alternate weather requirements. 

All flights would continue to be dispatched and followed by a Great Lakes Aviation dispatcher.

All Great Lakes flights are conducted with two qualified crewmembers, effectively adding to the 

safety margin when weather becomes a factor. The Dispatchers / Pilot in Command will have 

continuous communication ability between each other during each flight and throughout our 

entire route structure. Any changes in the airport weather or changes to the flight plan can easily 

be communicated without delay. 

While utilizing the FAR 121.619 alternate weather requirements, Great Lakes would effectively 

continue to operate at the same safety levels as any equivalent 121 air carrier. With the 

technological advances in weather forecasting, improved weather monitoring equipment, 

advanced communication capabilities, and improvements in Flight Crew training requirements, 

Great Lakes’ operation would continue to operate at a high level of safety.

PUBLIC INTEREST

If this exemption should be granted, we feel it is in the public interest for the following reasons:

This proposal would guarantee that the weather margins between the instrument 

approach minimums and the alternate weather requirements of 121.619, as well as the 

requirement for each flight to be dispatched by an approved dispatcher would provide a 

level of safety in the event un-forecasted weather should cause ceilings and visibilities to 

drop and still allow enough margin to complete the flight.

Having all operations (121 and 135) dispatched using the same alternate weather 

requirements will create consistency between operations, thus reducing possible errors 

in determining alternate correct weather minimums and the possible ramifications of 

those errors. 
1022 Airport Parkway ♦ Cheyenne, WY 82001 ♦ (307) 432-7210 ♦ Fax (307) 432-7001

SUMMARY

Great Lakes Aviation, Lt., holder of operating certificate GLBA031A, petitions the use of 

FAR 121.619 alternate weather requirements in lieu of the requirements of 135.223 for all flights 

conducted under FAR 135 under the basis that the carrier currently dispatches all 121 and 135 

flights in accordance with the requirements set forth in FAR 121 Subpart U. 

This is contingent upon the following requirements:

1) All FAR 135 flights are to be dispatched, and under continuous surveillance by a Great

Lakes Aviation dispatcher, trained in accordance with Great Lakes’ approved Dispatcher 

program.

2) All FAR 135 flights will be dispatched in accordance with FAR 121 Subpart U.

3) Each dispatcher will be provided a system to display the location of each flight and 

current/significant weather. 

4) The dispatch system will have a system to alert the dispatcher when there is a change to 

a weather forecast, METAR, or a special weather update. 

5) Great Lakes Aviation will provide a means of communication to allow all flight crews and 

dispatchers continuous communication ability for weather changes, dispatch release 

changes, etc. throughout Great Lakes’ route structure.

6) This relief will only applicable to airports within the 48 contiguous United States and the 

District of Columbia.

Thank you for your consideration of this request of exemption. I can be reached by email or 

phone to answer any questions you may have. 

Email: jlinnebur@flygreatlakes.com

Phone: 307-432-7210

Respectfully;

Joseph Linnebur

Director of Operations

Great Lakes Airlines

1022 Airport Parkway

Cheyenne, WY 82001