Avionics News April 2013 - 62

industry

What

?

Radial
ARE WE ON
S T O R Y

B Y

J O H N

F

or instrument pilots, the single most common
opportunity to find oneself calling the helpful
technicians at a local avionics shop is detailed in
Federal Aviation Regulation 91.171. It dictates that very
high frequency omnidirectional range (VOR) navigation
receivers cannot be used for instrument flight rules flights
unless tested, using a Federal Aviation Administration-

VOR Checks
approved test signal, or a designated VOR checkpoint
(which may be on an airport or at some point on an airway), or using an in-flight test procedure, or by comparing bearings on two separate VOR receivers either on the
ground or in flight. The required tolerance is plus or minus
4 degrees for ground tests and plus or minus 6 degrees in
flight.
Every time this test is conducted, there’s a possibility
the required tolerance won’t be met, and the avionics shop
62

avionics news

•

april

2013

D .

R U L E Y

is likely to be presented with a frustrated pilot who just
discovered the IFR flight he or she planned can’t proceed
until the problem is addressed.
I’m all too familiar with this scenario, as an instrumentrated pilot based at Modesto, Calif., where winter months
mean fog and low ceilings. After flying a wide range of
airplanes as a renter, sole owner and co-owner, I’ve had
experience with this from the pilot’s side. This led me to
ask what the situation looks like from the avionics side of
the house. The result has been educational, to say the least.
First, a brief review of how the VOR system works. The
ground station generates a directional VHF radio beam that
rotates at 30 hertz. Coincident with that directional beam is
an omnidirectional time signal, also operating at 30 hertz.
When both signals are received at the same time, you’re
on the 0 degree radial (magnetic North) or its complement
(180 degrees). Other directions are indicated by the difference in phase between the two signals. Station identification, using our old friend, Morse Code, is modulated on top
of the two signals, and optionally voice may be added, as
well.
The system is subject to three broad classes of errors:
1. Transmitter error: Basically a function of how



Avionics News April 2013

Table of Contents for the Digital Edition of Avionics News April 2013

Point of Communication
AEA Now
The View From Washington
International News and Regulatory Updates
Breakthrough
Member Profile
Digital Displacement and Fusion
Avionics News Through the Years
A Conversation With...
The Race to ADS-B Out
AEAviators
NextGen Status Report
Member Profile
Esterline CMC Electronics
What Radial Are We On?
AEA Offers Free NCATT Certifications and Endorsements at 2013 Convention
Work On Your Business, Not In Your Business
Business Basics
Survey Reveals Hiring Trends for the Aviation Industry
Meet the AEA Awards Nominees
What's New
Before & After
Avionics News April 2013 - Intro
Avionics News April 2013 - Cover1
Avionics News April 2013 - Cover2
Avionics News April 2013 - 1
Avionics News April 2013 - 2
Avionics News April 2013 - 3
Avionics News April 2013 - Point of Communication
Avionics News April 2013 - 5
Avionics News April 2013 - AEA Now
Avionics News April 2013 - 7
Avionics News April 2013 - 8
Avionics News April 2013 - 9
Avionics News April 2013 - 10
Avionics News April 2013 - 11
Avionics News April 2013 - 12
Avionics News April 2013 - 13
Avionics News April 2013 - The View From Washington
Avionics News April 2013 - 15
Avionics News April 2013 - International News and Regulatory Updates
Avionics News April 2013 - 17
Avionics News April 2013 - 18
Avionics News April 2013 - 19
Avionics News April 2013 - Breakthrough
Avionics News April 2013 - 21
Avionics News April 2013 - 22
Avionics News April 2013 - 23
Avionics News April 2013 - 24
Avionics News April 2013 - 25
Avionics News April 2013 - Member Profile
Avionics News April 2013 - 27
Avionics News April 2013 - 28
Avionics News April 2013 - 29
Avionics News April 2013 - Digital Displacement and Fusion
Avionics News April 2013 - 31
Avionics News April 2013 - 32
Avionics News April 2013 - 33
Avionics News April 2013 - 34
Avionics News April 2013 - 35
Avionics News April 2013 - Avionics News Through the Years
Avionics News April 2013 - 37
Avionics News April 2013 - A Conversation With...
Avionics News April 2013 - 39
Avionics News April 2013 - The Race to ADS-B Out
Avionics News April 2013 - 41
Avionics News April 2013 - 42
Avionics News April 2013 - 43
Avionics News April 2013 - AEAviators
Avionics News April 2013 - 45
Avionics News April 2013 - NextGen Status Report
Avionics News April 2013 - 47
Avionics News April 2013 - 48
Avionics News April 2013 - 49
Avionics News April 2013 - 50
Avionics News April 2013 - 51
Avionics News April 2013 - Member Profile
Avionics News April 2013 - 53
Avionics News April 2013 - 54
Avionics News April 2013 - 55
Avionics News April 2013 - Esterline CMC Electronics
Avionics News April 2013 - 57
Avionics News April 2013 - 58
Avionics News April 2013 - 59
Avionics News April 2013 - 60
Avionics News April 2013 - 61
Avionics News April 2013 - What Radial Are We On?
Avionics News April 2013 - 63
Avionics News April 2013 - 64
Avionics News April 2013 - 65
Avionics News April 2013 - 66
Avionics News April 2013 - 67
Avionics News April 2013 - AEA Offers Free NCATT Certifications and Endorsements at 2013 Convention
Avionics News April 2013 - 69
Avionics News April 2013 - 70
Avionics News April 2013 - 71
Avionics News April 2013 - Work On Your Business, Not In Your Business
Avionics News April 2013 - 73
Avionics News April 2013 - 74
Avionics News April 2013 - 75
Avionics News April 2013 - 76
Avionics News April 2013 - 77
Avionics News April 2013 - Business Basics
Avionics News April 2013 - 79
Avionics News April 2013 - 80
Avionics News April 2013 - 81
Avionics News April 2013 - 82
Avionics News April 2013 - 83
Avionics News April 2013 - Survey Reveals Hiring Trends for the Aviation Industry
Avionics News April 2013 - 85
Avionics News April 2013 - Meet the AEA Awards Nominees
Avionics News April 2013 - 87
Avionics News April 2013 - 88
Avionics News April 2013 - 89
Avionics News April 2013 - 90
Avionics News April 2013 - 91
Avionics News April 2013 - 92
Avionics News April 2013 - 93
Avionics News April 2013 - 94
Avionics News April 2013 - 95
Avionics News April 2013 - What's New
Avionics News April 2013 - 97
Avionics News April 2013 - 98
Avionics News April 2013 - 99
Avionics News April 2013 - 100
Avionics News April 2013 - Before & After
Avionics News April 2013 - 102
Avionics News April 2013 - 103
Avionics News April 2013 - 104
Avionics News April 2013 - Cover3
Avionics News April 2013 - Cover4
https://www.nxtbook.com/allen/avne/60-10
https://www.nxtbook.com/allen/avne/60-9
https://www.nxtbook.com/allen/avne/60-8
https://www.nxtbook.com/allen/avne/60-7
https://www.nxtbook.com/allen/avne/60-6
https://www.nxtbook.com/allen/avne/60-5
https://www.nxtbook.com/allen/avne/60-4
https://www.nxtbook.com/allen/avne/60-3
https://www.nxtbook.com/allen/avne/60-2
https://www.nxtbook.com/allen/avne/60-1
https://www.nxtbook.com/allen/avne/59-12
https://www.nxtbook.com/allen/avne/59-11
https://www.nxtbook.com/allen/avne/59-10
https://www.nxtbook.com/allen/avne/59-9
https://www.nxtbook.com/allen/avne/59-8
https://www.nxtbook.com/allen/avne/59-7
https://www.nxtbook.com/allen/avne/59-6
https://www.nxtbook.com/allen/avne/59-5
https://www.nxtbook.com/allen/avne/59-4
https://www.nxtbook.com/allen/avne/59-3
https://www.nxtbook.com/allen/avne/59-2
https://www.nxtbook.com/allen/avne/59-1
http://www.brightcopy.net/allen/avne/58-12
http://www.brightcopy.net/allen/avne/58-11
http://www.brightcopy.net/allen/avne/58-10
http://www.brightcopy.net/allen/avne/58-9
http://www.brightcopy.net/allen/avne/58-8
http://www.brightcopy.net/allen/avne/58-7
http://www.brightcopy.net/allen/avne/58-6
http://www.brightcopy.net/allen/avne/58-5
http://www.brightcopy.net/allen/avne/58-4
http://www.brightcopy.net/allen/avne/58-3
http://www.brightcopy.net/allen/avne/58-2
http://www.brightcopy.net/allen/avne/58-1
http://www.brightcopy.net/allen/avne/57-12
http://www.brightcopy.net/allen/avne/57-11
http://www.brightcopy.net/allen/avne/57-10
http://www.brightcopy.net/allen/avne/57-9
http://www.brightcopy.net/allen/avne/57-8
http://www.brightcopy.net/allen/avne/57-7
http://www.brightcopy.net/allen/avne/57-6
http://www.brightcopy.net/allen/avne/57-5
http://www.brightcopy.net/allen/avne/57-4
http://www.brightcopy.net/allen/avne/57-3
http://www.brightcopy.net/allen/avne/57-2
http://www.brightcopy.net/allen/avne/57-1
http://www.brightcopy.net/allen/avne/56-12
http://www.brightcopy.net/allen/avne/56-11
http://www.brightcopy.net/allen/avne/56-10
http://www.brightcopy.net/allen/avne/56-9
http://www.brightcopy.net/allen/avne/56-8
http://www.brightcopy.net/allen/avne/56-7
http://www.brightcopy.net/allen/avne/56-6
http://www.brightcopy.net/allen/avne/56-5
http://www.brightcopy.net/allen/avne/56-4
http://www.brightcopy.net/allen/avne/56-3
http://www.brightcopy.net/allen/avne/56-2
http://www.brightcopy.net/allen/avne/56-1
http://www.brightcopy.net/allen/avne/55-12
http://www.brightcopy.net/allen/avne/55-11
http://www.brightcopy.net/allen/avne/55-10
http://www.brightcopy.net/allen/avne/55-9
http://www.brightcopy.net/allen/avne/55-8
http://www.brightcopy.net/allen/avne/55-7
http://www.brightcopy.net/allen/avne/55-6
http://www.brightcopy.net/allen/avne/55-5
http://www.brightcopy.net/allen/avne/55-4
http://www.brightcopy.net/allen/avne/55-3
http://www.brightcopy.net/allen/avne/55-02
http://www.brightcopy.net/allen/avne/55-01
http://www.brightcopy.net/allen/avne/54-12
http://www.brightcopy.net/allen/avne/54-11
http://www.brightcopy.net/allen/avne/54-10
http://www.brightcopy.net/allen/avne/54-9
http://www.brightcopy.net/allen/avne/54-8
http://www.brightcopy.net/allen/avne/54-7
http://www.brightcopy.net/allen/avne/54-6
http://www.brightcopy.net/allen/avne/54-5
http://www.brightcopy.net/allen/avne/54-4
http://www.brightcopy.net/allen/avne/54-3
http://www.brightcopy.net/allen/avne/54-2
http://www.brightcopy.net/allen/avne/54-1
http://www.brightcopy.net/allen/avne/53-12
http://www.brightcopy.net/allen/avne/53-11
http://www.brightcopy.net/allen/avne/53-10
http://www.brightcopy.net/allen/avne/53-9
http://www.brightcopy.net/allen/avne/53-8
http://www.brightcopy.net/allen/avne/53-7
http://www.brightcopy.net/allen/avne/53-6
http://www.brightcopy.net/allen/avne/53-5
http://www.brightcopy.net/allen/avne/53-4
http://www.brightcopy.net/allen/avne/53-3
http://www.brightcopy.net/allen/avne/53-2
http://www.brightcopy.net/allen/avne/53-1
http://www.brightcopy.net/allen/avne/52-12
http://www.brightcopy.net/allen/avne/52-11
http://www.brightcopy.net/allen/avne/52-10
http://www.brightcopy.net/allen/avne/52-9
http://www.brightcopy.net/allen/avne/52-8
https://www.nxtbook.com/allen/avne/52-7
https://www.nxtbook.com/allen/avne/52-6
https://www.nxtbook.com/allen/avne/52-5
https://www.nxtbook.com/allen/avne/52-4
https://www.nxtbook.com/allen/avne/52-3
https://www.nxtbook.com/allen/avne/52-2
https://www.nxtbook.com/allen/avne/52-1
https://www.nxtbook.com/allen/avne/51-12
https://www.nxtbook.com/allen/avne/51-11
https://www.nxtbook.com/allen/avne/51-10
https://www.nxtbook.com/allen/avne/51-9
https://www.nxtbook.com/allen/avne/51-8
https://www.nxtbook.com/allen/avne/51-7
https://www.nxtbook.com/allen/avne/51-6
https://www.nxtbook.com/allen/avne/51-5
https://www.nxtbook.com/allen/avne/51-4
https://www.nxtbook.com/allen/avne/51-3
https://www.nxtbook.com/allen/avne/51-2
https://www.nxtbook.com/allen/avne/51-1
https://www.nxtbook.com/allen/avne/50-12
https://www.nxtbook.com/allen/avne/50-11
https://www.nxtbook.com/allen/avne/50-10
https://www.nxtbook.com/allen/avne/50-9
https://www.nxtbook.com/allen/avne/50-8
https://www.nxtbook.com/allen/avne/50-7
https://www.nxtbook.com/allen/avne/50-6
https://www.nxtbook.com/allen/avne/50-5
https://www.nxtbook.com/allen/avne/50-4
https://www.nxtbook.com/allen/avne/50-3
https://www.nxtbook.com/allen/avne/50-2
https://www.nxtbook.com/allen/avne/50-1
https://www.nxtbook.com/allen/avne/49-12
https://www.nxtbook.com/allen/avne/49-11
https://www.nxtbook.com/allen/avne/49-10
https://www.nxtbook.com/allen/avne/49-9
https://www.nxtbook.com/allen/avne/49-8
https://www.nxtbook.com/allen/avne/49-7
https://www.nxtbook.com/allen/avne/49-6
https://www.nxtbook.com/allen/avne/49-5
https://www.nxtbook.com/allen/avne/49-4
https://www.nxtbook.com/allen/avne/49-3
https://www.nxtbook.com/allen/avne/49-2
https://www.nxtbook.com/allen/avne/49-1
https://www.nxtbook.com/allen/avne/48-12
https://www.nxtbook.com/allen/avne/48-11
https://www.nxtbookmedia.com