High Altitude and Terrain Effects 1/17/2019

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. 1/17/2019

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 1/17/2019

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 1/17/2019

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. 1/17/2019

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 1/17/2019

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Searching Mountainous Terrain Contour Search Procedures 1/17/2019

Visual Search Procedures 1/17/2019

Flight Near Mountainous Terrain Enter terrain from above and always have an escape route in mind. 1/17/2019

Contour Search 1/17/2019

Contour Search 1/17/2019

Searching a Cove 1/17/2019

Searching a Steep Valley 1/17/2019

Scanning Sloping Terrain 1/17/2019

Scanning Sloping Terriain 1/17/2019

Electronic Search Procedures 1/17/2019

Terrain Blocking of Electronic Signals NO SIGNAL SIGNAL HEARD! ELT 1/17/2019

Electronic Search: Altitude Selection Higher altitudes allow for reception of the ELT signal at greater distances. ELTs transmit on 121.5 MHz and 243.0 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 1/17/2019

Terrain and Altitude Considerations End Test Time 1/17/2019