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Upskill / Aircraft Maintenance / Pneumatics, air conditioning and pressurisation

Pneumatics, air conditioning and pressurisation

Bleed air, packs, recirculation, cabin pressure control, testing, troubleshooting and MEL relief under CS-25 and 14 CFR Part 25 (ATA 21 and 36)

By Aerospace Garage Desk · In practice · 40 minutes · 24 narrated pages

What you will be able to do

  • ✓ Explain cabin altitude and differential pressure, trace the air path from bleed source to outflow valve, and calculate cabin altitude from flight level and differential.
  • ✓ Describe bleed air regulation, crossbleed, APU and ground air, and duct leak detection, and apply a fault-isolation sequence to a bleed leak.
  • ✓ Describe how air cycle packs cool and dry the air, how the bleedless 787 architecture differs, and diagnose a poorly performing pack from test readings.
  • ✓ Explain mixing, recirculation, HEPA filtration and zone temperature control against the CS-25 and Part 25 ventilation and air quality requirements.
  • ✓ Describe pressure control, safety valves, warnings and ground pressurisation testing, and plan cabin rates of climb and descent.
  • ✓ Apply MEL relief for air system items and draw the lessons of ATSB investigation AO-2007-062 for maintenance and dispatch.

Course content

Session 1 · Supply, condition, contain: how the air systems fit together

1.1

  1. Why the cabin is pressurised · free preview
  2. The air path from engine to outflow valve
  3. The certification rules for cabin air and pressure
  4. Worked example: cabin altitude from differential pressure
Session 2 · The pneumatic system: bleed air, APU and ground air

1.2

  1. Taking air from the engine
  2. Crossbleed, APU bleed and ground air
  3. Overheat and leak detection
  4. Worked example: isolating a wing bleed leak
Session 3 · Air-conditioning packs and the bleedless alternative

1.3

  1. The air cycle machine
  2. Getting the water out, and protecting the pack
  3. The bleedless architecture
  4. Worked example: a pack that runs warm
Session 4 · Distribution, recirculation, filtration and temperature

1.4

  1. Mixing, recirculation and HEPA filters
  2. Zone temperature control and trim air
  3. Cabin air quality, ozone and fume events
  4. Worked example: dispatching with one pack inoperative
Session 5 · Pressurisation control, safety valves and testing

1.5

  1. The controller and the outflow valve
  2. Safety valves, warnings and oxygen presentation
  3. Maintaining and testing pressurisation
  4. Worked example: planning the cabin rate schedule
Session 6 · Faults, MEL relief and depressurisation

1.6

  1. Troubleshooting the air systems
  2. MEL relief for air systems
  3. Depressurisation: warnings, oxygen and what follows
  4. From the investigation file: VH-VBC, one bleed, one pack

Who this course is for

  • Engineers isolating bleed leaks and poorly performing air-conditioning packs
  • Technicians running ground pressurisation tests and outflow valve checks
  • Maintenance control staff applying MEL relief to air system items

You need: Basic aircraft systems knowledge and simple arithmetic.

Upskill courses are for professional development and are not approved by any aviation authority. Learner Terms

Course content © Aerospace Garage Limited. All rights reserved.