Military and political tensions in countries such as Afghanistan, Belarus, and Ukraine continue to cause operational headaches for airlines that are obliged to fly grossly inefficient diversions to avoid potentially dangerous airspace. Further impacting their operational flexibility in these situations are the limitations of current emergency oxygen systems for passengers when a rapid descent has to be made while avoiding the risk of hypoxia.
Current regulations for pressurized aircraft certified to operate above 25,000 feet, based on ICAO Standards and Recommended Practices, require that in the event of emergency cabin oxygen being deployed due to a failure of the pressurization system, flight crew must quickly descend to below 10,000 feet. Most current oxygen systems use a chemical generator that, once activated, can provide around 22 minutes of oxygen. In most terrains that isn’t problematic but it is in mountainous regions where the risk of controlled flight into terrain prohibits flight at lower altitudes, forcing airlines to make long detours.
This constraint has been particularly acute for carriers flying between Europe and Asia, although it also impacts some routes between South and North America. In order to avoid Afghanistan airspace, operators are having to divert northeast over Mongolia or head south over Saudi Arabia to bypass the Himalayan mountain peaks, over 100 of which exceed an elevation of 23,600 feet.
This challenge has inspired breathing technology group Caeli Nova to rethink how emergency oxygen supplies are delivered in aircraft—a process that it claims hasn’t fundamentally advanced for some 40 years. In September, the UK-based company launched a collaboration with Airbus to assess the potential for its new Cordillera system to be installed on the manufacturer’s airliners (both for new-build models and for retrofit), with the capability to provide more than 100 minutes of oxygen supply.
The company claims this would give airlines the flexibility to use airways such as L888 over the Himalayas, more efficiently circumventing Afghanistan. It could also apply to useful transcontinental routes such as P500 over Pakistan and Tajikistan, and potentially for some routes between South and North America.
Caeli Nova is not the only company addressing these wasteful limitations, which is increasingly unacceptable to the airline industry in view of both elevated fuel costs and the strong imperative to reduce carbon emissions. In 2022, Safran Aerosystems intends to introduce a new version of its Hi-Eff passenger oxygen system, which would provide up to 47 minutes of hypoxia protection.
The French group’s existing Hi-Eff system is already certified and operational on the Airbus A220 narrowbody, as well as Embraer’s E2 regional jet and the Bombardier Global 7500 long-range business jet. Safran is now seeking certification on other aircraft types. According to the company, the system consists of a chemical generator and a passenger mask optimized “to either extend the duration of hypoxia protection for a given mass and space, or for a given hypoxia protection duration, reduce the size and mass of the system.”
Collins Aerospace also produces both chemical and gaseous based oxygen systems for commercial airliners. According to Sondra Radcliffe, the U.S. group's general manager for oxygen and passenger service units, these provide between 12 and 22 minutes of oxygen and are designed to match the descent profile of the aircraft's route.
Radcliffe told AIN that Collins' latest PulseOx gaseous system is a pulse oxygen generating system, "designed to be flexible to meet any descent profile of a commercial aircraft." The equipment only provides oxygen when it is needed, making supplies last longer than traditional constant flow systems. The new system also reduces weight and volume by eliminating the need for heavy regulator units and extensive oxygen lines throughout the airframe. The flow of oxygen is initiated by detecting each passenger's breathing pattern.
According to CEO Tim Wakeford, the main difference with Caeli Nova's system is based on its premise that it is not necessary, or even desirable, to give passengers a 100 percent oxygen blend, allowing for the concentration of oxygen in the supply to be reduced, and so extending the limits for protection.
“We have consistently asked the question, how can we enable the human body to use the supply of oxygen more efficiently,” Wakeford told AIN. “Taking that approach makes you look at all aspects of the oxygen delivery to the passenger in the system design. As a result, Cordillera will enable safe oxygenation for passengers at a higher altitude and for the required duration to safely access the most challenging routes across high terrain regions.”
The technology used by Caeli Nova is explained in its European patent, granted in 2019. This outlines a novel CO2 enrichment technique that reduces the amount of oxygen needed by adding CO2 both from an external source and from the passenger's own inhalation process, while still providing the necessary oxygen saturation at high altitudes.
Caeli Nova has yet to disclose the unit cost of the Cordillera hardware but estimates that the cost of retrofitting existing airliners could be between $20,000 and $30,000. It says the work could be completed during an extended layover at a location with a suitably qualified MRO provider.
The company aims to earn a supplemental type certificate for the modification by the middle of 2022, and the first retrofits might be conducted during a C-check maintenance visit and will most likely involve a widebody airliner or a long-range A321XLR. It is in talks with four airlines that could be prospective early adopters of the technology. Wakeford says could result in fuel savings of between $5 million and $20 million per year.
Passengers, he explained, should be unaware of the change, even though new masks will be part of the retrofit. Caeli Nova’s engineering team is aiming for the new hardware to occupy the same space in the aircraft.
This article was amended on January 7, 2022, to add further information about new oxygen systems provided by Collins Aerospace.
https://www.ainonline.com/aviation-news/air-transport/2021-12-23/new-approach-emergency-cabin-oxygen-could-cut-fuel-burn
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