What is a typical consequence if one environmental control pack on ATR fails?

What is a typical consequence if one environmental control pack on ATR fails?

• A. The cabin becomes unpressurized immediately
• B. A failed pack may reduce cooling/heating and may require alternate procedures
• C. The aircraft's electrical power is lost
• D. The cabin temperature remains unaffected

Answer: (B)

Two environmental control packs condition and supply cabin air. If one pack fails, the other pack can still provide conditioned air, but cooling and heating capacity is reduced. That means the crew may need to follow alternate procedures or rely on the remaining pack to manage cabin temperature, which can lead to a less effective temperature control. This situation does not cause immediate cabin depressurization or loss of electrical power, and the cabin temperature would not remain completely unaffected because the available conditioning would be reduced.

Two environmental control packs condition and supply cabin air. If one pack fails, the other pack can still provide conditioned air, but cooling and heating capacity is reduced. That means the crew may need to follow alternate procedures or rely on the remaining pack to manage cabin temperature, which can lead to a less effective temperature control. This situation does not cause immediate cabin depressurization or loss of electrical power, and the cabin temperature would not remain completely unaffected because the available conditioning would be reduced.