CFI Pop Quiz #308 - Distance

[Chris Burgess]

When planning a distance flight, true course measurements on a Sectional Aeronautical Chart should be made at a meridian near the midpoint of the course because the

A) values of isogonic lines change from point to point.
B) angles formed by lines of longitude and the course line vary from point to point.
C) angles formed by isogonic lines and lines of latitude vary from point to point.

 

[Paul_Zurawski]

I know the isogonic value changes along the course....gonna go with (A)

 

[mark treidel]

Sorry Paul but I wont fly your 6 to Benson days.
'B' is correct.
Sectional charts are made on a grid in which the meridians of longitude are nonparallel straight lines that all meet at the earth's poles. When flight-planning, you have to measure the true course from the mid-meridian to get an average true course.

 

[Aussie_Paul]

I hathz ze feelzing thataa after theeez alcohol wearsth off it willthz be za(B)

Authie Paulthz

 

[Paul_Zurawski]

Been so long since I plotted anything on a sectional. After I answered, I thought about it, and dug up an old sectional. Gonna copy off Mark...agree with (B)

 

[Gary_in_Orygun]

Heck with a sectional, I'm just gonna punch in my destination on the GPS.

 

[mark treidel]

gps

gps

Heck with a sectional, I'm just gonna punch in my destination on the GPS.

Thats because you're young Gary, & tecnologically advanced. Us old fashioned types have to refer to the days of leather helmets & paper charts flapping in the breeze.

 

[birdy]

Where me nose goes, i goes.

 

[JByrd]

Bee.

Jim

 

[Chris Burgess]

"B" is correct. When planning a distance flight, true course measurements on a Sectional Aeronautical Chart should be made at a meridian near the midpoint of the course because the (B) angles formed by lines of longitude and the course line vary from point to point.

"A" is a stand alone correct statement, but it is not where you measure your true course line, making this one the easy mistake. Mark gave a good explanation of the correct answer.

BTW, If you are on a checkride with me, your GPS will fail about 10 miles out.!!!