High Altitude Operations Flashcards

Question

cabin differential pressure

Answer 1

difference in pressure between the cabin and the outside air

Answer 2

limits the amount of air taken from turbo by accelerating air to sonic speed creating a shock wave which acts as a barrier air is very hot and must be run through a heat exchanger to cool it after cooling air is sent to cabin via heating and ventilation outlets

Answer 3

outflow valve - allows air to exit safety/dump valve - if outflow valves dump will release excess pressure vacuum relief valve - allows ambient air into cabin

Answer 4

cabin/differential pressure indicator - like altimeter but has two references outside and cabin pressure cabin rate of climb indicator - indicates rate of change in cabin pressure

Answer 5

pressure 10.9 psi

Answer 6

pressure 4.8 psi

Answer 7

:lack of sufficient oxygen in the body cells or tissues caused by an inadequate supply of oxygen, inadequate transportation of oxygen, or inability of the body tissues to use i. at high altitudes, pressure of oxygen on lungs is reduced, thus, the ability for the body to absorb oxygen is reduced

Answer 8

the amount of time in which a person is able to effectively or adequately perform flight duties with an insufficient altitude / standard ascent rate / after rapid decompression 18,000 20-30 minutes / 10-15 minutes 22,000 10 minutes / 5 minutes 35,000. 30-60 seconds / 15-30 seconds 50,000. 9-12 seconds / 5 seconds

Answer 9

can produce toxic symptoms such as bronchial cough, fever, vomiting, lowered energy i. significant periods of time are required before this occurs (usually 1-2 days)

Answer 10

nitrogen in the body changing from liquid form to gaseous state due to a dramatic reduction in surrounding atmospheric pressure i. AIM 8-1-2 recommends for flights below 8000 ft (cabin pressure), minimum 12 hours for non-decompression dives, and 2 hours for decompression dives. for flights above 8000 ft, 24 hours minimum.

Answer 11

i. minimum crew must use oxygen between 12,500 and 14,000 (inclusive) for any period over 30 minutes ii. minimum crew must use oxygen above 14,000 at all times iii. all passengers must be provided with oxygen above 15,000

Answer 12

i. above FL250, minimum of 10-minutes of supplemental oxygen available for each passenger ii. above FL350, at least one pilot must be wearing and using an oxygen mask; unless at or below FL410, if there are two pilots at the controls, and both have quick donning type mask that can be put on and working within 5 seconds iii.even with quick donning masks, if one pilot leaves, other must wear and use oxygen until other pilot returns

Answer 13

(1) travels east at approximately 50-200 kts (2) caused by large temperature differences aloft (3) has a meandering path that is constantly changing (4) closer to the equator in the winter, farther in the summer i. general circulation patterns move south in the winter due to less heating activity

Answer 14

(1) :phenomenon of turbulence associated with high altitude winds, and not associated with clouds (2) can be caused by wind shear, mountain waves, low pressures aloft, etc (3) difficult to forecast since there are no visual signs of it.

Answer 15

(1) whether portable or installed, oxygen is stored in high pressure tanks (usually around 1800-2200 PSI) (2) 22 cu ft container will supply 4 people at 18,000 ft for up to 1.5 hours (3) aviation oxygen should be the only oxygen to be used (100% oxygen) i. industrial oxygen is not made for breathing, and has impurities in it. ii. medical oxygen may contain to much moisture which could freeze at low temperatures (4) oxygen systems require periodic refill, inspection, and servicing i. AF/D tell what airports have oxygen available (5) oxygen duration charts allow calculations of time available based on passengers and system PSI

Answer 16

most common type of system for piston aircraft as well as for passengers in turboprop and jets. (1) overview i.simplicity keeps maintenance costs down, reduces malfunction possibility ii. not adequate above 25,000 ft. (although certified up to 41,000 iii. designs may include constant-flow, adjustable-flow, altitude-compensated flow iv. available as built-in system, or portable system (2) mask styles i. oronasal rebreather - covers both nose and mouth, and includes a bag to allow reuse of exhaled oxygen ii. cannula breathing device - oxygen is supplied to the nose only, allowing use of normal communication methods (not certified as high as oronasal rebreathers)

Answer 17

supply oxygen only when the user inhales through the mask (1) depending on altitude the supplied mixture of oxygen to cabin-air are automatically adjusted (2) demand-type masks have a tight seal to avoid dilution by cabin air, and are safe up to 40,000 ft

Answer 18

(1) available on airliners, oxygen generators use a chemical reaction to produce oxygen for a set amount of time. (2) each passenger has an individual “supply” from a generator

Answer 19

the compression of air in the aircraft cabin in order to maintain a cabin altitude lower than the actual flight altitude most light aircraft compress air to the cabin via the turbocharger or an engine-driven pump

Answer 20

i. an outflow valve keeps pressure constant by releasing excess pressure into the atmosphere ii.a cabin altitude can be manually selected via a cabin altitude controller, and if needed regulated via a backup control to a safety dump valve iii. vacuum relief valve prevents cabin pressure from becoming lower than ambient pressure in the case of a rapid descent iv. a heat exchanger conditions the air before entry into the cabin

Answer 21

:maximum allowable difference between atmospheric pressure and cabin pressure i.different for each aircraft (see POH)

Answer 22

the inability of the aircraftʼs pressurization system to maintain its designed pressure schedule

Answer 23

i.can be caused by a malfunction in the system, or by structural damage to the aircraft ii.may result in cabin fog due rapid cooling of relatively moist air iii.decompression of small cabins is more critical than large cabins given same hole or conditions (i) primarily due to differences in cabin volume

Answer 24

i. slow decompression - may be difficult to detect. many systems include audible and visual warnings of high cabin altitudes ii. explosive decompression - an extremely dangerous condition in which he aircraft decompresses faster than the lungs can decompress. (i) typically occurs in less than 0.5 seconds (ii) lung damage can occur (iii) flying debris may cause further injury iii. rapid decompression - decompression that occurs quickly, but is slower than the rate at which the lungs can decompress.

Answer 25

i. use supplemental oxygen as quickly as possible ii. descend as quickly as possible to a safe altitude (i) a balance between reaching a safe altitude, and taking care of the engine must be made (most significantly in piston engines) High Altitude Operations - rev. 2/25/09 iii. see emergency descent below for procedure

Answer 26

(1) at high altitudes engine driven fuel pumps may be subject to fuel vaporization i. boost pumps are typically installed to address this situation

Answer 27

(1) as with any altitude, if severe turbulence is encountered, maintain appropriate airspeed, and attempt to keep wings level, and heading approximately correct (2) accept changes in altitude and airspeed as long as pitch is relatively constant

Answer 28

(1) when using an oxygen system, ensure properly operation by testing the system before takeoff (2) when using a pressurized system, refer to the POH to see what preflight actions are required before operation

Answer 29

(1) in an emergency descent, the main objective is to lose altitude as quickly (and safely as possible) i. may be due to an inflight fire, cabin depressurization, etc. (2) this objective must be balanced with the need to preserve the engine. i. especially in Pistons, shock cooling can have significant detrimental effects (3) Procedure i. if necessary, don oxygen mask as soon as possible ii. slow the aircraft to proper speeds to extend gear and flaps iii. set propeller to high rpm (to help act as an aerodynamic brake) iv. reduce power as much as practicable v. if time permits, contact controller and notify of emergency descent for traffic avoidance purposes vi. initiate a 30°- 45° turn to allow traffic clearing, reduce vertical component of lift, and maintain positive “G” loading on the aircraft vii. through descent, ensure: (i) airspeed does not exceed appropriate limitations (Vfe, Vle, Vne) (ii) engine temperature does not cool to rapidly a. if necessary add power to keep temperature up

Answer 30

(1) possible symptoms of a slow leak de-pressurization (2) upon simulated depressurization i. fly the airplane! ii. don oxygen masks asap iii. refer to emergency descent procedures

Answer 31

confusion, restlessness, difficulty breathing, rapid heart rate, bluish skin, headache, anxiety