DGCA A/C Systems 11. Pressurization Systems

 

Results

Q1. Main and nose wheel bays are:

Correct answer is – unpressurized

Q2. Normal maximum negative differential pressure is:

Correct answer is – when atmospheric pressure exceeds cabin pressure by the amount permitted by the system controls

Q3. When would the negative differential limit be reached/exceeded?

Correct answer is – Rapid descent when AC descends below cabin altitude

Q4. $A/C$ in level flight: if cabin altitude increases, pressure diff:

Correct answer is – decreases

Q5. In level pressurized flight what does the outflow valve do?

Correct answer is – Adjust to provide constant flow, and is normally partially open

Q6. In a turbo-compressor or bootstrap system the cooling air is:

Correct answer is – ram air

Q7. The rate of change of cabin pressure should be kept to the minimum. This is more important:

Correct answer is – in descent

Q8. A cabin humidifier is used:

Correct answer is – at high altitude

Q9. Fatigue life of the fuselage is based on the:

Correct answer is – number of pressurization cycles

Q10. If the forward oil seal in an axial flow compressor fails, cabin air will be:

Correct answer is – contaminated

Q11. Rate of change of cabin altitude is shown on a:

Correct answer is – special gauge

Q12. Cabin discharge valve (pneumatic) is supplied with:

Correct answer is – cabin and static pressure

Q13. What is the purpose of the duct relief valve?

Correct answer is – To prevent damage to the ducts

Q14. What system is installed to control the air conditioning?

Correct answer is – Impingement type dehydrator and humidifier

Q15. How is the (charge) air cooled in a bootstrap (turbo-compressor) system?

Correct answer is – By expanding over turbine driving compressor

Q16. At the max differential phase, the discharge phase is:

Correct answer is – open

Q17. What is the purpose of inward relief valves?

Correct answer is – To prevent negative differential

Q18. On a ground pressurization test, if the cabin suffers a rapid de-pressurization:

Correct answer is – water precipitation will occur

Q19. A heat exchanger functions by:

Correct answer is – passing charge air through ducts and cool air around ducts

Q20. Maximum differential pressure:

Correct answer is – is the maximum authorized pressure difference between the inside of the fuselage and the atmospheric ambient pressure

Q21. A humidifier is fitted to:

Correct answer is – increase the moisture content in the air when operating at high altitude

Q22. If the discharge or outflow valve closes:

Correct answer is – the safety valve would limit the positive pressure difference

Q23. Air for conditioning and pressurization is taken from:

Correct answer is – the engine compressor or cabin compressor

Q24. Safety valves are biased:

Correct answer is – inwards

Q25. Cabin compressors:

Correct answer is – increase their flow in proportion to increases of altitude differential pressure and reduction in engine rpm in order to maintain the mass flow

Q26. In a pressurization circuit the sequence of operation is for the:

Correct answer is – outflow valve to operate before the safety valve

Q27. In the cruise at 30 000 ft the cabin altitude is adjusted from 4000 ft to 6000 ft:

Correct answer is – cabin differential will decrease

Q28. An aircraft climbs from sea level to 16000 ft at 1000 ft per min, the cabin pressurization is set to climb at 500 ft per min to a cabin altitude of 8000 ft. The time taken for the cabin to reach 8000 ft is:

Correct answer is – the same time as it takes the aircraft to reach 16 000 ft

Q29. The aircraft inhibiting switch connected to the A/C landing gear:

Correct answer is – stops pressurizing on the ground and ensures that there is no significant pressure differential

Q30. Negative differential is limited by:

Correct answer is – inward relief valve

Q31. To maintain a steady and constant airflow regardless of altitude or cabin pressure:

Correct answer is – a mass flow controller is fitted

Q32. The term “pressurization cycle” means:

Correct answer is – air introduced into a fuselage under pressure until the time the air is released

Q33. Inward Relief Valves operate:

Correct answer is – automatically when there is a negative diff

Q34. Safety valves operate:

Correct answer is – at higher than maximum differential

Q35. Ditching Cocks are operated:

Correct answer is – to shut all outflow valves

Q36. Duct Relief Valves operate when:

Correct answer is – excessive pressure builds up in the air conditioning system supply ducts

Q37. During a normal pressurized cruise, the discharge valve position is:

Correct answer is – partially open

Q38. A dump valve:

Correct answer is – is controlled manually

Q39. When air is pressurized the % of oxygen:

Correct answer is – remains the same

Q40. If pressure is manually controlled:

Correct answer is – care should be taken to ensure climb/descent rates are safe

Q41. An aircraft is prevented from pressurizing on the ground by:

Correct answer is – inhibiting microswitches on the landing gear

Q42. If the pressurization air is passed over the cold air unit compressor it:

Correct answer is – increases the charge air temperature

Q43. If the cabin pressure increases in level flight does the cabin VSI shows:

Correct answer is – rate of descent

Q44. The term pressure cabin is used to describe:

Correct answer is – the ability to pressurise the aircraft to a higher than ambient pressure

Q45. A pressurization system works by:

Correct answer is – essentially constant input mass flow and variable output

Q46. When air is pressurized by an engine driven compressor, it is also:

Correct answer is – heated

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