ECS Exam 2025 With Correct Answers o o o o o
What does the AMS use bleed air for? - correct answer • ECS (heating & cooling)
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• Engine start
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• Pressurization
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• Engine and wing anti-ice
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• Water pressure
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• Hot air leak detection
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How many AMS controllers are installed? - correct answer One controller with 2 channels which control the
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respective onside system o o
What happens if a channel fails? - correct answer The remaining channel is able to control the entire AMS
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What provides air for the AMS? - correct answer • Engine bleeds
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• APU bleed
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• External Pneumatic Source
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What is bleed air used for? - correct answer • ECS (heating & cooling)
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• Engine start
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• Engine and wing anti-icing
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• Water pressurization
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, What is external pneumatic air used for? - correct answer • ECS on the ground
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• Engine start on the ground
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Where is the external ground source panel located? - correct answer Lower fairing between the wings
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What is the primary use for APU bleed air? - correct answer • ECS on the ground
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• Engine starting on the ground
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• Assist with engine start (< FL210)
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• Bleed source for pressurization, heating, and cooling (< 15,000 ft MSL)
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Can engine bleed air flow-back to the APU? - correct answer No. A check valve prevents flow-back
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Where is bleed air tapped from the engines? - correct answer • 6th and 10th stage compressors (EBV and HSV
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respectively) o
• System alternates between valves to regulate an adequate and safe pressure
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What is normal pressure for any engine operation? - correct answer 45 psi
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What is the purpose of the pre-cooler? - correct answer Cools the bleed air coming from the engine to the AMS
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What cools the pre-cooler? - correct answer • Ground N1 fan
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• Flight N1 fan or ram air
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What does the Overheat Detection System (ODS) observe? - correct answer • Engine bleeds and packs
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• APU bleed
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• Plumbing for the wing and engine anti-icing system
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What does the AMS use bleed air for? - correct answer • ECS (heating & cooling)
o o o o o o o o o o o o o o o o
• Engine start
o o o
• Pressurization
o o
• Engine and wing anti-ice
o o o o o
• Water pressure
o o o
• Hot air leak detection
o o o o
How many AMS controllers are installed? - correct answer One controller with 2 channels which control the
o o o o o o o o o o o o o o o o o
respective onside system o o
What happens if a channel fails? - correct answer The remaining channel is able to control the entire AMS
o o o o o o o o o o o o o o o o o o
What provides air for the AMS? - correct answer • Engine bleeds
o o o o o o o o o o o o
• APU bleed
o o o
• External Pneumatic Source
o o o
What is bleed air used for? - correct answer • ECS (heating & cooling)
o o o o o o o o o o o o o o
• Engine start
o o o
• Engine and wing anti-icing
o o o o o
• Water pressurization
o o
, What is external pneumatic air used for? - correct answer • ECS on the ground
o o o o o o o o o o o o o o o
• Engine start on the ground
o o o o o
Where is the external ground source panel located? - correct answer Lower fairing between the wings
o o o o o o o o o o o o o o o
What is the primary use for APU bleed air? - correct answer • ECS on the ground
o o o o o o o o o o o o o o o o o
• Engine starting on the ground
o o o o o o
• Assist with engine start (< FL210)
o o o o o o o
• Bleed source for pressurization, heating, and cooling (< 15,000 ft MSL)
o o o o o o o o o o o
Can engine bleed air flow-back to the APU? - correct answer No. A check valve prevents flow-back
o o o o o o o o o o o o o o o o
Where is bleed air tapped from the engines? - correct answer • 6th and 10th stage compressors (EBV and HSV
o o o o o o o o o o o o o o o o o o o o
respectively) o
• System alternates between valves to regulate an adequate and safe pressure
o o o o o o o o o o o
What is normal pressure for any engine operation? - correct answer 45 psi
o o o o o o o o o o o o
What is the purpose of the pre-cooler? - correct answer Cools the bleed air coming from the engine to the AMS
o o o o o o o o o o o o o o o o o o o o
What cools the pre-cooler? - correct answer • Ground N1 fan
o o o o o o o o o o o
• Flight N1 fan or ram air
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What does the Overheat Detection System (ODS) observe? - correct answer • Engine bleeds and packs
o o o o o o o o o o o o o o o o
• APU bleed
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• Plumbing for the wing and engine anti-icing system
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