6 - Pack Altimeter

 VFR Day Equipment Requirements FAR 91.205

ATOMATO FLAMES

• Airspeed
• Tacometer (for each engine)
• Oil Pressure Gauge (for each Engine)
• MAgnetic Direction Indicatior
• Altimeter 
• Temperature Gague (for each liquid cooled engine)
• Oil Temperatue Gague (for each air cooled engine)
• Fuel Gague (for each tank)
• Landing Gear Position Indicator
• AntiCollision Light
• MAnifold Pressure Gague (For Each Altitude Engine)
• ELT
• SeatBelts for each occupant

Altimeter

Types of Altitude

Indicated Altitude 
- Whatever the Altimeter is reading (regardless of what the altimeter is set at) 
- eg 625' MSL (Mean Sea Level) Not always accurate

True Altitude 
- Real Altitude
- True Altitude Above Sea Level
- Hight Above Sea Level Expressed in MSL 

Absolute Altitude
- Hight above Surface (Ground)
- Expressed in AGL (Above Ground Level)

Pressure Altitude
- Standard Datum Plane (29.92" Hg)
- if Kelsi meter is adjuster to 29.29"HG you reading is hight about standard datum plane

Density Altitude
- Pressure Altitude Corrected for non-standard temperature 
- The 4 H's - Hight, Hot, Heavy (Weight), Humid  - Aircraft performance could suffer
- Density Altitude is Pressure Altitude and Temperature this is how aircraft performance is calculated

True: Actual height above sea level.
Indicated: What’s read on the instrument.
Absolute: Height above ground level (agl).
Pressure: What’s read on the instrument with the pressure set to standard (29.92 inches).
Density: Pressure altitude corrected for nonstandard temperature (what the aircraft thinks the altitude is).

Altimeter Error 

- Calibrated at 15Deg C (59 Def F)
- Higher than 15C = Higher than you think
- Lower than 15C = Lower than you think
- AIM 7-3-1 (Table  Temp vs Hight Above Airport In Feet)

- High to Low .. Look out below (from a airport with higher barometric pressure to an airport with lower barometric pressure, look out below meaning the airport hight is lower that altimeter indicated if the Altimeter is not adjusted to the lower barometric pressure)

- From low to high - High in the Sky

• If your true Altitude might stay the same, the absolute altitude may change with the turaine
• you can subtract the True Altitude from Ground Elevation

Reference

https://www.youtube.com/watch?v=q27N5EFWmpM