The Effect of Density Altitude on
Carrier Operations and FCLP training Locations.
I contend that the Navy altitude requirement for FCLP training of 200 feet or
below is not a valid requirement, because it does not consider density altitude.
Density altitude is a combination of barometric pressure, temperature and
humidity. Higher temperatures, altitude, and increased moisture reduce the
density of the air. A reduction in air density reduces the engine power, reduces
aerodynamic lift and reduces drag.
Aircraft performance is based on density altitude rather than true altitude. The
aircraft behaves as if it were at the density altitude rather than the actual altitude
above sea level.
An aircraft landing or taking off during high-density altitude conditions will have a
higher approach speed, longer landing roll and longer takeoff roll.
So how does all this aviation jargon affect FCLP training and carrier landings?
The Navy says that they must train as they operate in the real world and we
agree.
However, a few examples will demonstrate that the training at OLF Coupeville
does not closely replicate actual carrier operations because of the density
altitude factor.
The first set of examples use an “average day” at each location, and an FAA
“standard day” barometric pressure of 29.92. Data for weather conditions at each
location were taken from USA.com. Airfield elevations were taken from FAA
Airfield Diagrams. Carrier elevations are mean sea level plus 60 feet to the flight
deck. Note that Persian Gulf operations have a higher density altitude than ANY
of the examples.
The airfield closest in “average day” density altitude to current Persian Gulf
operations is El Centro CA. The airfield with the most dissimilar density altitude is
OLF Coupeville. Put another way, OLF Coupeville provides the least realistic
training of any of the other alternatives.
OLF Coupeville
Elevation 200
Air Temp 51
Barometric Pressure 29.92
Dew point 35
Density Altitude 337
Lemoore NAS CA
Elevation 230
Air Temp 62
Barometric Pressure 29.92
Dew point 56
Density Altitude 678
Moses Lake WA
Altitude 1189
Air Temp 50
Barometric Pressure 29.92
Dew point 45
Density Altitude 1010
El Centro CA
Elevation -40
Air Temp 75
Barometric Pressure 29.92
Dew point 40
Density Altitude 1284
Persian Gulf Operations
Elevation 60
Air Temp 88
Barometric Pressure 29.92
Dew point 65
Density Altitude 2182
The following examples use an average July day at each location. Again note
that Persian Gulf operations have a higher density altitude than any of the other
locations. The airfield with the closest density altitude to current combat ops is
Moses Lake WA. Moses Lake is also the closest airfield to Whidbey Island.
Again, OLF Coupeville provides the least realistic training.
OLF Coupeville
Elevation 200
Air Temp 72
Barometric Pressure 29.92
Dew point 35
Density Altitude 337
Lemoore NAS CA
Elevation 230
Air Temp 80
Barometric Pressure 29.92
Dew point 76
Density Altitude 1691
El Centro CA
Elevation -40
Air Temp 92
Barometric Pressure 29.92
Dew point 90
Density Altitude 2132
Moses Lake WA
Altitude 1189
Air Temp 83
Barometric Pressure 29.92
Dew point 71
Density Altitude 2770
Persian Gulf Operations
Flight Deck Elevation 60
Air Temp 96
Barometric Pressure 29.92
Dew point 78
Density Altitude 2817
Neal Sims, Coupeville, WA