Welcome Guest. Sign in or Signup

1 Answers

Seeking Answer

Asked by: 3839 views Aircraft Systems, Commercial Pilot

The question below appears supposedly on a major US airline’s pilot knowledge test. Mathematically, how is the answer solved? You are on the XYZ VOR 090 radial at 20 DME. You are instructed to proceed direct to the XYZ VOR 180 radial at 70 DME. The direct, no wind heading is: a) 185° b) 190° c) 195° d) 200°

Ace Any FAA Written Test!
Dauntless Aviation's GroundSchool series of apps are the smart pilot's choice for fast and effective FAA knowledge test prep.
Actual, up-to-date FAA questions Polished user experience
Best explanations in the business Free lifetime updates!
Private Pilot IFR Commercial Pilot CFI ATP Sport Pilot Sport Pilot Instructor Parachute Rigger Aviation Mechanic (A&P)
You can get the app now and be studying right away. Available for PC, Mac, iPhone/iPad, and Android.

1 Answers



  1. Wes Beard on Sep 17, 2015

    This is a simple triangle formula. The key to understanding the answer is to determine your reference point. For my answer, the reference point is going to be 20 NM out on the 090 degree radial. Notice, the airplane is east so that direction will be positive and west will be negative. In the same regard, we will fly south, so a south direction will be positive and north would be negative.

    Since it is a right triangle, the formula A^2 + B^2 = C^2 will yield the distance flown from the 090 radial to the 180 radial at the given distances. 20^2 + 70^2 = 72 NM.

    to find the heading, it is the formula tan(x) = opposite / adjacent. or tan(x) = 20/70 which will result in a 74 degree angle. 270 degrees (to fly to the station) – 74 equals 196 degrees.

    Thus the answer is 196 degrees. Skyvector shows the heading as 197 degrees.

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.