1. High Altitude and Terrain Effects
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2. High Altitude Considerations
Density Altitude
Varies with elevation and temperature
Reduced hp and prop efficiency
Affects takeoff, climb, true air speed
Critical performance parameters adversely affected
Increased Takeoff Distances
Reduced Climb Performance
Increased Landing distances
Refer to chapter 6 of student manual
One inch of barometric pressure is equivalent to 1000 feet (29.92 vs 30.92)
Pressure Altitude - altitude indicated when altimeter set to 29.92
As pressure altitude and temperature increase, density altitude increases.
Density Altitude - pressure altitude corrected for temperature - it’s like a wind chill chart for altitude. The aircraft will perform according to the density altitude, not the field elevation!
Density altitude chart - enter at bottom of chart with temperature; go up to slanted line representing pressure altitude; go left to read density altitude on vertical axis of the chart.
As the air gets warmer, the molecules spread apart and therefor create less lift and less power for the engine.
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3. Density Altitude 1/17/2019 18,000 ft = 7.5 lbs per sq in
Sea Level = 15 lbs per sq in
18,000 ft = 7.5 lbs per sq in
10,000 ft = 10 lbs per sq in
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4. Effects of Density Altitude
Takeoff Roll at Sea Level
Takeoff Roll at 5,000 ft Density Altitude
Climb at LOWER Density Altitude
Always calculate takeoff performance.
It will take more runway to lift off and more distance to climb at higher density altitude.
Climb at HIGHER Density Altitude
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5. Effects of Altitude on Crew Member Performance
Hypoxia
Lack of oxygen to the brain
Loss of night vision as low as 5,000 feet
For most people altitudes above 12,000 feet result in a loss of judgment , coordination, memory, and alertness
Medication and other factors
Ear Block
Yawn, swallow, tense muscles in throat
Valsalva maneuver
Sinus Block
Don’t fly if you’re not well
Medication
Refer to 6.3 of student manual
Hypoxia can be insidious. It can affect you without your being aware.
The percentage of oxygen in the atmosphere is constant at about 21%, regardless of altitude. Low atmospheric pressure at altitude prevents oxygen from being absorbed into the red blood cells at high altitude
FAR’s require the pilot to breathe supplemental oxygen above 14,000.
Flight at 12,500 is limited to 30 minutes.
Ear block usually occurs during descent.
Tell the pilot as soon as an ear or sinus block occurs. It can be very painful and can cause permanent damage.
Can’t scan well while you are in pain.
Medications can affect your performance.
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6. MOUNTAINOUS TERRAIN PROCEDURES
Locate Grid/Area (with & without elec nav)
Establish Search Altitude
Contour Search Procedures
Canyon Search Procedures
Ridge Crossing procedures
Communications Procedures
Wing/updrafts/downdrafts
Mountain Wave Effect
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8. 1/17/2019

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10. 1/17/2019

11. 1/17/2019

12. 1/17/2019

13. 1/17/2019

14. 1/17/2019

15. 1/17/2019

16. Searching Mountainous Terrain
Contour Search
Procedures
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17. Visual Search Procedures
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18. Flight Near Mountainous Terrain
Enter terrain from above and always have an escape route in mind.
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19. Contour Search
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20. Contour Search
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21. Searching a Cove
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22. Searching a Steep Valley
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23. Scanning Sloping Terrain
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24. Scanning Sloping Terriain
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25. Electronic Search Procedures
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26. Terrain Blocking of Electronic Signals
NO SIGNAL
SIGNAL
HEARD!
ELT
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27. Electronic Search: Altitude Selection
Higher altitudes allow for reception of the ELT signal at greater distances.
ELTs transmit on MHz and MHz, both of which limit reception to “line of sight.”
Terrain will block ELT signals.
HIGHER is therefore usually BETTER to acquire a signal.
Medium altitude is generally better for searching (after signal heard)
3,000 to 5,000 AGL
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28. Terrain and Altitude Considerations
End
Test Time
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