CA.VIII.A. High Altitude Operations Flashcards
What cabin pressure altitudes requires supplemental oxygen for flight crew and passengers?
FLIGHT CREW
- Above 12,500 ft cabin pressure altitude and 14,000 ft when at those altitudes for more than 30 min.
- Above 14,000: at all times.
PASSENGERS
- All occupants mus be *provided above cabin pressure altitude of 15,000 ft.
Though not legally required, when does the FAA recommend flight crew to make use of supplemental oxygen?
When operating at altitudes above 10,000 ft during the day
and 5,000 ft at night.
Why does the FAA specifically recommend using oxygen above 5,000ft at night? Why lower than during the day?
- Night vision tends to degrade rapidly above 5,000 ft.
- Eyes use rods at night, and rods are much more sensitive to oxygen deprivation than cones.
- Pilots are generally more fatigued at night, which aggravates the effects of hypoxia.
What are the supplemental oxygen requirements that apply to aircraft with
pressurized cabins?
General requirements still apply.
ABOVE FL 250: at least a 10 minute supply of supplemental oxygen must be available for each occupant.
ABOVE FL350: at least one pilot needs to be using supplemental oxygen - HOWEVER there is an exception if quick-donning masks are available. As
long as there are two pilots at the controls, neither needs to be using supplemental oxygen.
ABOVE FL410: This exception goes away
What qualifies as a quick donning mask?
Can be secured on the face
with one hand and start supplying oxygen within 5 seconds.
What are some of the symptoms you would expect from hypoxic hypoxia at high altitudes?
Cyanosis (blue fingernails
and lips)
Euphoria
Headache
Decreased reaction to stimuli
Increased reaction time
Visual impairment
Drowsiness
Lightheaded or dizzy
Tingling or numbness
Tunnel vision.
What are the 3 components of most oxygen systems?
1) Storage system (e.g. bottle)
2) delivery system
3) mask or nasal cannula.
Name the 3 types of oxygen delivery systems.
1) Continuous flow: Typically
used at 28,000 feet and lower.
2) Diluter demand: Gives oxygen during inhalation, and stops
the flow during exhalation.
Helps conserve oxygen.
Typically used up to FL400.
3) Pressure demand: Forceful O2 flow that in a sense, pressurize the lungs to a lower
altitude, thus allowing you to fly at altitudes above 40,000
feet, where 100% oxygen without positive pressure is
insufficient.
What type of oxygen are pilots required to use?
Aviator’s Breathing Oxygen.
What checklist can pilots use to ensure a proper preflight check of the oxygen system?
REMEMBER PRICE!
- Pressure: ensure pressure and quantity are sufficient.
- Regulator: inspect for proper function)
- Indicator: shows a steady flow of oxygen when in use
- Connections: all are secured.
- Emergency: Brief the passengers on location and equip.
When would you need a high-altitude endorsement?
When acting as pilot-in-command of a pressurized aircraft with a maximum operating altitude or service ceiling above 25,000 feet mean sea level (MSL).
Explain how basic aircraft pressurization works?
- Pressurized air from the compressor section of the engine is allowed to bleed into the aircraft.
- Heat Exchanger cools the hot
compressed air before it enters the cabin. - Outflow and safety valves control the exit of this pressurized air to maintain a consistent cabin altitude, or dump cabin pressure in an emergency.
What is Time of Useful Consciousness?
Period of time from exposure to an oxygen-poor environment, to the time when an individual is no longer capable of taking proper corrective and protective action. Impaired performance may be immediate.
What TUC would you expect at 40,000 ft?
Approximately 15-20 seconds.
What TUC would you expect at 20,000 ft?
5-12 minutes or more
