Post by Tom Goodrick on Sept 19, 2010 15:27:48 GMT -5
Regarding the TAS/IAS matter, you mentioned we should all go back to basic Private Pilot groundschool. While shelling the litter box this morning of the cats who live in my laundry room, I noticed a faded old book on a shelf. It was the book my tow boys used in their Private Pilot Ground School 26 years ago. (Neither one passed the written. They wouldn't let me help them.)
EXCERPS FROM PRIVATE PILOT TEST BOOK
Many people are confused about true airspeed and indicated airspeed. To make matters worse, there are also "Equivalent" airspeed (used by USAF) and "Calibrated" airspeed used by Cessna and some other manufacturers (probably an FAA requirement) in their manuals. In the answer to question 1003, you will see clearly how confused the people are who wrote this book (supposedly used by the FAA and designated examininers as the official test book). The USAF just does not like the word "calibrated" but Equivalent means the same thing. I'll show two calibration tables taken from actual aitcraft manuals later. For now consider that we just need to worry about "True" and "Indicated" as shown in TAS, KTAS and IAS or KIAS. They used to be given in mph but the K means Knots.
A look at questions and answers for the Private Pilot's exam, 1984, FAA-T-8080-1 (Pub 1984 by Aiviation Supplies & Academics, Inc): (Note that the first question was numbered 1001.)
Questions (Answers will be printed in the next note.) Choose only one answer.
1003. If a pilot plans to land at an airport where the elevation is 7,500 ft, the indicated approach airspeed should be
1-higher than that used for a sea level airport, and some power should be used until touchdown.
2-the same as that used at a sea level airport.
3-lower than that used at a sea level airport.
4-higher than that used at a sea level airport.
Note: There are questions about glider performance and about landing distance using supplied charts in which no mention is made of whether looking at IAS or TAS. In each case IAS should be used to fly the plane with a conversion to TAS for use in the charts. One chart for landing distance for a Cessna 150, uses 60 mph IAS for approach and gives landing distance for sea level, 2500 ft, 5000 ft and 7500 ft. This might give you a clue to the answer to 1003.
(Many questions pertain to helicopter, balloon, blimp and glider flight for those separate exams. These quetions appear in the list with no indication they are not for fixed-wing pilots. One quetion stopped me dead. It started out: "Before takeoff you should burn all fuel tanks because ...." There were a few questions where the answer was that there was no correct answer!)
Questions 1108 to 1117 refer to a figure showing a properly marked airspeed indicator. The questions deal with the meaning of the color bands and marks. Nowhere does it say that this is "indicated airspeed." But this was before some idiot built an altitude compensation into the indicator so it could show "true airspeed". Back in those days we figured that the airspeed indicator showed us the indicated airspeed. (Duh!)
1118. The pitot system provides impact pressure for only the
1-airspeed indicator, vertical-speed indicator and altimeter
2-altimeter and vertical-speed indicator
3-vertical-speed indicator
4-airspeed indicator
1124. If the pitot tube and outside static vents or ports were clogged, which instrument or instruments would be affected?
1-The airspeed indicator, altimeter and turn-and-bank indicator
2-The altimeter, vertical-speed indicator and airspeed indicator would provide inaccurate instrument readings.
3-The only instruments that would provide provide erroneous indications would be the airspeed indicator and the altimeter.
4-The airspeed indicator would indicate excessively high airspeeds.
1125. Which instrument(s) will become inoperative if the pitot tube becomes clogged?
1-Altimeter
2-Vertical speed
3-Airspeed
4-Altimeter and airspeed
1126. Which instrument(s) will become inoperative if the static vents become clogged?
1-Airspeed only
2-Altimeter only
3-Airspeed and altimeter only
4-Airspeed, altimeter and vertical speed
The following question is just one I like. All student pilots should pay attention to this:
1153. What makes an airplane turn?
1-Centrifugal force
2-Rudder and aileron
3-Horizontal component of lift
4-Rudder, aileron and elevator
1164. The purpose of flaps is to
1-enable the pilot to make steeper approaches to a landing without increasing airspeed.
2-enable the pilot to reduce the speed for the approach to a landing.
3-enlarge or control the wing to vary the lift.
4-create more drag in order to utilize power on the approach.
(Several answers are almost correct, but one is best.)
1176. Under what conditions can an airplane be stalled?
1-Only when the nose is high and the airspeed is low.
2-Only when the airspeed decreases to the published stalling speed.
3-At any airspeed and in any flight attitude.
4-Only when the nose is too high in relation to the horizon.
1177. The angle of attack at which an airplane wing stalls will
1-increase if the CG is moved forward
2-change with an increase in gross weight
3-remain the same regardless of gross weight
4-decrease if the CG is moved aft.
1178. As altitude increases, the indicated airspeed at which a given airplane stalls in a particular configuration will
1 - decrease as the true airspeed decreases.
2 - decrease as the true airspeed increases.
3 - remain the same.
4 - increase because the air density becomes less.
I'll give the answers tomorrow.
EXCERPS FROM PRIVATE PILOT TEST BOOK
Many people are confused about true airspeed and indicated airspeed. To make matters worse, there are also "Equivalent" airspeed (used by USAF) and "Calibrated" airspeed used by Cessna and some other manufacturers (probably an FAA requirement) in their manuals. In the answer to question 1003, you will see clearly how confused the people are who wrote this book (supposedly used by the FAA and designated examininers as the official test book). The USAF just does not like the word "calibrated" but Equivalent means the same thing. I'll show two calibration tables taken from actual aitcraft manuals later. For now consider that we just need to worry about "True" and "Indicated" as shown in TAS, KTAS and IAS or KIAS. They used to be given in mph but the K means Knots.
A look at questions and answers for the Private Pilot's exam, 1984, FAA-T-8080-1 (Pub 1984 by Aiviation Supplies & Academics, Inc): (Note that the first question was numbered 1001.)
Questions (Answers will be printed in the next note.) Choose only one answer.
1003. If a pilot plans to land at an airport where the elevation is 7,500 ft, the indicated approach airspeed should be
1-higher than that used for a sea level airport, and some power should be used until touchdown.
2-the same as that used at a sea level airport.
3-lower than that used at a sea level airport.
4-higher than that used at a sea level airport.
Note: There are questions about glider performance and about landing distance using supplied charts in which no mention is made of whether looking at IAS or TAS. In each case IAS should be used to fly the plane with a conversion to TAS for use in the charts. One chart for landing distance for a Cessna 150, uses 60 mph IAS for approach and gives landing distance for sea level, 2500 ft, 5000 ft and 7500 ft. This might give you a clue to the answer to 1003.
(Many questions pertain to helicopter, balloon, blimp and glider flight for those separate exams. These quetions appear in the list with no indication they are not for fixed-wing pilots. One quetion stopped me dead. It started out: "Before takeoff you should burn all fuel tanks because ...." There were a few questions where the answer was that there was no correct answer!)
Questions 1108 to 1117 refer to a figure showing a properly marked airspeed indicator. The questions deal with the meaning of the color bands and marks. Nowhere does it say that this is "indicated airspeed." But this was before some idiot built an altitude compensation into the indicator so it could show "true airspeed". Back in those days we figured that the airspeed indicator showed us the indicated airspeed. (Duh!)
1118. The pitot system provides impact pressure for only the
1-airspeed indicator, vertical-speed indicator and altimeter
2-altimeter and vertical-speed indicator
3-vertical-speed indicator
4-airspeed indicator
1124. If the pitot tube and outside static vents or ports were clogged, which instrument or instruments would be affected?
1-The airspeed indicator, altimeter and turn-and-bank indicator
2-The altimeter, vertical-speed indicator and airspeed indicator would provide inaccurate instrument readings.
3-The only instruments that would provide provide erroneous indications would be the airspeed indicator and the altimeter.
4-The airspeed indicator would indicate excessively high airspeeds.
1125. Which instrument(s) will become inoperative if the pitot tube becomes clogged?
1-Altimeter
2-Vertical speed
3-Airspeed
4-Altimeter and airspeed
1126. Which instrument(s) will become inoperative if the static vents become clogged?
1-Airspeed only
2-Altimeter only
3-Airspeed and altimeter only
4-Airspeed, altimeter and vertical speed
The following question is just one I like. All student pilots should pay attention to this:
1153. What makes an airplane turn?
1-Centrifugal force
2-Rudder and aileron
3-Horizontal component of lift
4-Rudder, aileron and elevator
1164. The purpose of flaps is to
1-enable the pilot to make steeper approaches to a landing without increasing airspeed.
2-enable the pilot to reduce the speed for the approach to a landing.
3-enlarge or control the wing to vary the lift.
4-create more drag in order to utilize power on the approach.
(Several answers are almost correct, but one is best.)
1176. Under what conditions can an airplane be stalled?
1-Only when the nose is high and the airspeed is low.
2-Only when the airspeed decreases to the published stalling speed.
3-At any airspeed and in any flight attitude.
4-Only when the nose is too high in relation to the horizon.
1177. The angle of attack at which an airplane wing stalls will
1-increase if the CG is moved forward
2-change with an increase in gross weight
3-remain the same regardless of gross weight
4-decrease if the CG is moved aft.
1178. As altitude increases, the indicated airspeed at which a given airplane stalls in a particular configuration will
1 - decrease as the true airspeed decreases.
2 - decrease as the true airspeed increases.
3 - remain the same.
4 - increase because the air density becomes less.
I'll give the answers tomorrow.