What is critical is that internally generated horsepower (being proportional to oxygen intake) is a function of the dry air component of ambient pressure, and not simply pressure altitude
, which is the sum of water vapor component and dry air pressures.
Figure 15 indicates the flight path, pressure altitude
, CAS, Mach number, and fuel flow of the cases that satisfy the following conditions:
The plots shown in Figures 1, 2, 3, 4, 5 show plots of these parameters or called roll back indicators charts for selected pressure altitude
test conditions conducted on this test article.
I REALLY did appreciate BC Webster's concerns (letter Aug 11), but to put minds at rest - as aircraft freight bays are at the same pressure altitude
as the passenger cabin, max of 8,000 ft, which is equivalent to a drop in pressure from take-off of approx' 0.25 bar (3.6 psi).
is what the altimeter would say if the pressure scale were set to 29.92, a theoretical standard.
Pressure Altitude/Density Altitude (PADA)--computes the following parameters: sea level pressure (SLP), altimeter setting (ALSTG), pressure altitude
(PA), density altitude (DA) and the standard atmosphere based on the upper/lower station pressure and the following optional data fields: station elevation (for ALSTG, PA, DA), 12-hour mean temperature (for SLP), temperature (for DA) and dew point for DA.
The FLT function handles pressure altitude
and density altitude calculations.
Temperature and pressure come into play here, since performance charts are based on pressure altitude
adjusted for temperature (density altitude).
Carbon monoxide inhaled in smoking or from exhaust fumes, lowered hemoglobin (anemia), and certain medications can reduce the oxygen-carrying capacity of the blood to the degree that the amount of oxygen provided to body tissues will already be equivalent to the oxygen provided to the tissues when exposed to a cabin pressure altitude
of several thousand feet."
The main mission parameters to be defined are altitude (pressure altitude
is the reading of an altimeter when adjusted to the standard MSL (mean sea level) atmospheric pressure of 1013.25 mbar (29.98 inches of mercury); it does not correspond to the actual elevation): PA, temperature T), gas density, and air density.
The laws of aerodynamics are what they are, and keeping an eye on the OAT/FAT, the pressure altitude
, the torque gauge, and the trusty NATOPS pocket checklist has traditionally been the key to success in coping with each scenario.