Flight Crew Supplemental Oxygen - Oxygen Systems - Airframes & Aircraft Systems #54

Summary

This lesson covers the regulatory requirements for supplemental oxygen systems on aircraft. It details the mandatory oxygen supply durations for flight and cabin crews at various altitudes, emphasizing the importance of oxygen to prevent hypoxia. The script explains the storage in high-pressure cylinders, the functioning of the pressure regulator, and the safety mechanisms like discharge indicators. It also describes the different types of oxygen regulators, focusing on the demand regulator's operation and the quick-donning masks necessary for high-altitude flights. The lesson ensures pilots understand the critical role of oxygen systems in aviation safety.

Takeaways

• 🌐 Supplemental oxygen is essential for crew and passengers to breathe normally at high altitudes where hypoxia can occur.
• ⏱ For pressurized aircraft, supplemental oxygen must be available for crew above 10,000 ft for over 30 minutes and above 13,000 ft continuously.
• 💡 The minimum oxygen supply required for flight crew depends on the aircraft's certified flight altitude, ranging from 30 minutes to 2 hours.
• 🛫 On pressurized planes, passengers must have a minimum 10-minute oxygen supply when the cabin is above 15,000 ft.
• 🚫 Unpressurized aircraft require oxygen for the flight crew above 10,000 ft and for the cabin crew above 13,000 ft.
• 🔌 Aircrew supplemental oxygen is stored in high-pressure gas cylinders at 1,800 psi, with pressure reduced for use via a regulator.
• 🔍 Oxygen pressure is indicated on the flight deck, and excessive pressure is safely vented through a safety disc, indicated by a discharge indicator.
• 🎓 Flight crew systems are typically of the diluted demand type, with oxygen flow controlled by a demand regulator, which can supply oxygen on-demand or at a continuous flow.
• 🛑 In emergency situations, pilots can select 100% oxygen with positive pressure to ensure smoke is kept out and to increase oxygen saturation in the blood.
• 💬 Quick-donning masks are required for flight deck crew on aircraft with a maximum operating altitude above 25,000 feet, allowing one-handed fitting within 5 seconds.

Q & A

What is supplemental oxygen used for in aviation?

Supplemental oxygen is used to allow the crew and passengers to breathe normally at altitudes where they would not otherwise be able to do so without the onset of hypoxia.

At what altitudes is supplemental oxygen required for flight and cabin crews in pressurized aircraft?

Supplemental oxygen must be available for any time longer than thirty minutes that the cabin is between 10,000 and 13,000 feet, and for the entire time that the cabin is above 13,000 feet pressure altitude.

What is the minimum amount of supplemental oxygen required for flight tech on an airplane certified to fly up to 25,000 feet?

The minimum amount of supplemental oxygen to be carried must be sufficient for at least 30 minutes of use.

How much supplemental oxygen must be carried for airplanes certified to fly above 25,000 feet?

For airplanes certified to fly above 25,000 feet, there must be sufficient supplemental oxygen carried for two hours of use.

What is the requirement for supplemental oxygen for passengers on board a pressurized aircraft above 15,000 feet?

There must be sufficient supplemental oxygen carried on a pressurized aircraft to supply all of the passengers on board with oxygen when the cabin is above 15,000 feet pressure altitude with a minimum of ten minutes supply available.

At what altitudes must oxygen be available for the flight crew and cabin crew on unpressurized aircraft?

On unpressurized aircraft, oxygen must be available for the flight crew at all times above 10,000 feet, but the cabin crew oxygen must be available at all times above 13,000 feet, and at all times longer than 30 minutes above 10,000 feet.

How is oxygen stored in aircraft and at what pressure?

Aircrew supplemental oxygen is stored in high-pressure gas cylinders at a pressure of 1,800 pounds per square inch.

What is the purpose of the safety disc and discharge indicator on oxygen cylinders?

In the event of the pressure inside the cylinder becoming excessive, the cylinder is vented to the atmosphere through a safety disc. Indication of this fact is given by a discharge indicator located on the outer skin of the aircraft, which will show a red painted area if the green disc is ejected.

What type of oxygen system is generally used for flight crew systems and how does it work?

Flight crew systems are generally of the diluted demand type. In this system, the flow of oxygen to the flight crew masks is controlled by a demand regulator, which supplies oxygen on-demand depending on pilot selection, which can be oxygen diluted with cabin air, 100% oxygen, or 100% oxygen flowing continuously under a slight positive pressure.

What are the three pilot-controlled levers on the diluted demand regulator?

The three pilot-controlled levers on the diluted demand regulator are a supply lever with on-and-off positions, an oxygen selection lever with normal and 100% positions, and an emergency lever with normal, emergency, and test mask positions.

What is the purpose of the quick-donning mask for flight deck crew on aircraft operating above 25,000 feet?

The mask must be capable of being fitted with one hand in a maximum time of five seconds, and the pilot must be able to carry out normal communication tasks with the mask fitted. This ensures rapid deployment in emergency situations where immediate oxygen supply is necessary.