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Brainteasers

Mar. 22, 2007

Brainteasers
Interactive Quiz #118:
Cleared ILS Approach

"Four from the marker, maintain 2000 until established on the localizer, cleared ILS 22 approach." Readback correct. In a GPS world, the ground-based Instrument Landing System still breathes. See if you can keep the needles crossed.


INSTRUCTIONS: Answer the questions as best you can, then click on the "Score my quiz answers" button to see your score and read the explanations. If you don't like your score the first time around, you can change some of your answers and resubmit. To get the most out of this quiz, we suggest you keep trying until you get a perfect score.

NOTE: When more than one answer is true, only the most complete, correct answer will be scored as correct. The answers are assumed to apply within the United States unless otherwise noted.


1. Let's begin with who can fly an ILS approach by checking the veracity of this entire statement: We know it's an instrument procedure with lateral and vertical guidance, so VFR pilots may not utilize an ILS, or any of its components, even in VMC (visual meteorological conditions), unless authorized by an ATC clearance that includes the phrase "Maintain VFR."
a. True
b. False
2. Instrument-rated pilots are incredibly popular at parties. Why? Some say it's because by the time you've earned your instrument rating you've learned how to walk beneath a Cessna's wing without banging your head into the ailerons. Not true. Instrument pilots are cool because they understand AIM 1-1-9 and FAR 91.175, Takeoff and Landing Under IFR. At parties, the instrument pilots usually cluster together to discuss, among other things, the components of the ILS. Which components listed below are usually included in an operational Category I ILS? (Pick the best answer.)
a. Localizer, glide slope, outer marker, approach lights
b. Localizer, RAIM, radar, approach lights
c. Localizer Outer Marker (LOM), glide path, DME
d. Locator Outer Marker (LOM), glide slope, inner marker
3. The FAA definition of localizer course width is: "The angular displacement at any point along the course between a full "fly-left" (CDI needle fully deflected to the left) and a full "fly-right" indication (CDI needle fully deflected to the right." Normally, how many degrees wide is the localizer either side of centerline? (Don't confuse course width with service volume.)
a. 5 degrees either side of the course
b. 2.5 degrees either side of the course
c. 3 degrees either side of the course
d. 3.5 degrees either side of the course
4. Typically, where is the localizer transmitter antenna located?
a. Atop the control tower
b. At or near the approach end of the runway being served
c. At or near the departure end of the runway being served
d. Midway down a runway (and off to the side) so as to serve both ends
e. Terra Haute, Ind.
5. An ILS is a precision approach with vertical guidance. Typically, the GA pilot flies a Category I approach. Special authorization is needed for Cat II and III. The instrument pilot crosses the needles (localizer and glide slope) and follows them to a point about 200 feet above the ground, where the pilot must decide whether to continue down and land or add power to go missed approach. Everything in the FAA is labeled with an acronym, including FAA (Funny Acronym Agency), so the ILS descent minimum is referred to by its acronym:
a. MDA
b. DF
c. DA/DH
d. IAP
e. T/U
6. You're flying single-pilot, Part 91, not for hire, in a Piper Archer, IFR in the clag and wishing you had an EFVS-equipped Gulfstream G-4. You've grabbed the localizer and intercepted the glide slope needle from below. Everything looks good and you start down. This airport is located inside Class C airspace. After passing the FAF (final approach fix; for precision approaches, that's at glide-slope intercept) you call the control tower and are cleared to land. FAR 91.175 (c) allows an IFR instrument arrival, shooting an instrument approach, to operate below the published minimum altitudes (defined in the previous question) if (among other things):
a. The flight visibility, as the pilot sees it, is not less than the visibility prescribed in the standard instrument approach being used.
b. Tower visibility, as reported by the tower, is not less than the visibility prescribed in the standard instrument approach being used.
c. RVR, as reported by the tower, is not less than the visibility prescribed in the standard instrument approach being used.
d. The flight visibility, as the pilot sees it, is not less than the visibility prescribed in the standard instrument approach being used and as reported by the control tower.
7. Upon landing, you discover a winning Mega-Lotto ticket in your wallet. It's worth $300 million. After taxes, you have enough for that new EFVS-equipped Gulfstream and your first tank of gas. Not wishing to sound naïve around your new jet buddies -- who earned their money the old-fashioned way by being born into it -- you ask the dealer what EFVS means. She says EFVS allows you to descend below minimum instrument approach altitudes (with restrictions) and EFVS stands for:
a. Electronic Flight Vision System
b. Electronic Flight Vertical Sensor
c. Enhanced Flight Vertical System
d. Enhanced Flight Vision System
8. Think back to question # 3 when we asked about localizer width. Well, what do you suppose a full-needle deflection (full-scale fly-left to a full-scale fly-right) would be (in feet, not degrees) at the runway threshold (front course approach)? Not that you'd ever fly with the needles slamming from one stop to the other ...
a. 300 feet
b. 500 feet
c. 700 feet
d. 1700 feet
9. Because a localizer has a front course, it may also have a published back course approach. (Not always, so don't create your own approach thinking it'll work.) When flying the back course, the localizer needle will indicate reversed sensing, meaning if it's to the left you fly right and if to the right, fly left. That's brain teasing enough without reverse-sensing equipment, but a glide slope on a back course ILS requires even sharper attention. If you receive the glide slope on a back course approach, when no glideslope is published, you should:
a. Fly away from the glide slope needle to correct for reverse sensing
b. Fly toward the glide slope needle, since glide slopes are identical on either course
c. Ignore glide slope
d. Immediately go missed approach
10. Not everything has to work on an ILS for you to fly an instrument approach. Which of the ground-based components below, if inoperative, disqualify the instrument approach entirely?
a. Locator
b. Localizer
c. Glide Slope
d. Outer Marker
e. Approach Lights


If you enjoyed taking this interactive quiz and would like to see more like it, go to the AVweb Brainteaser page. And if you thought it was unfair, confusing, or a waste of time, we'd like you to tell us that, too. And if you have an idea for a subject that you think would make a good future Brainteaser quiz, be sure to let us know.

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