Course Deviation Indicator(CDI)
Definition
A needle showing lateral displacement from the desired course, whether VOR radial, localizer, or GPS track. Full-scale deflection represents different distances depending on the navigation source.
Why Course Deviation Indicator Matters for Pilots
Instrument knowledge is tested on every pilot certificate exam. Understanding how Course Deviation Indicator works helps you interpret cockpit information correctly and recognize instrument failures before they become emergencies. This knowledge is especially critical for instrument-rated pilots flying in reduced visibility.
Exam Tip
This concept is commonly tested in instruments-related questions on FAA and EASA exams. Make sure you can explain Course Deviation Indicator in your own words for the oral exam. Practice applying this concept to real-world scenarios, not just memorizing the definition.
Related Terms
Horizontal Situation Indicator(HSI)
A navigation instrument combining a heading indicator with VOR/ILS course deviat...
VHF Omnidirectional Range(VOR)
A ground-based radio navigation aid transmitting radials in all directions. Pilo...
Localizer(LOC)
The lateral guidance component of an ILS providing precise runway centerline ali...
Share this with a fellow pilot
Related Content
Detonation
Aviation glossary definition and exam tips.
Washout
Aviation glossary definition and exam tips.
Cumulonimbus
Aviation glossary definition and exam tips.
ATPL Theory Complete Guide
Master every subject covered in airline pilot exams.
Free Practice Exam
Test your aviation knowledge with real exam questions.
Study Course Deviation Indicator with Rotate
Unlock All Study Materials — $7.49/mo
1,800+ practice questions covering Course Deviation Indicator and every exam topic. Flashcards, study guides, and progress tracking. 94% first-attempt pass rate.
Test your knowledge
Think you understand Course Deviation Indicator? Challenge yourself with practice questions covering instruments and all other exam subjects.
Try Free Practice QuestionsMore Instruments Terms
Attitude Indicator(AI)
A gyroscopic flight instrument displaying the aircraft pitch and bank attitude r...
Heading Indicator(HI)
A gyroscopic instrument showing aircraft magnetic heading without the oscillatio...
Altimeter
A barometric instrument measuring altitude by sensing atmospheric pressure chang...
Airspeed Indicator(ASI)
An instrument measuring indicated airspeed by comparing pitot (dynamic plus stat...