Aviator emergency oxygen system

A method, a system, and an oxygen delivery boomlet are configured to provide an additional partial pressure of oxygen to an aviator. The boomlet includes a conduit configured to receive an oxygen flow from a positive pressure oxygen source. A nozzle is in communicative connection with the conduit such that the oxygen flow the conduit receives is conducted to the nozzle. The nozzle is configured to direct the conducted flow of oxygen to an interpalatine region of the aviator. The boomlet is configured for attachment to a microphone boom.

FIELD OF THE INVENTION

This invention relates generally to Aviation Safety and, more specifically, to Aviation Environmental Safety.

BACKGROUND OF THE INVENTION

On Oct. 25, 1999, about 1213 central daylight time (CDT), a Learjet Model 35, N47BA, operated by Sunjet Aviation, Inc., of Sanford, Fla., crashed near Aberdeen, S. Dak. The airplane departed Orlando, Fla., for Dallas, Tex., about 0920 eastern daylight time (EDT). Radio contact with the flight was lost north of Gainesville, Fla., after air traffic control cleared the airplane to flight level390. Several U.S. Air Force and Air National Guard aircraft intercepted the airplane as it proceeded northwest-bound.

The military pilots in a position to observe the accident airplane at close range stated (in interviews or via radio transmissions) that the forward windshields of the Learjet seemed to be frosted or covered with condensation. The military pilots could not see into the cabin. They did not observe any structural anomaly or other unusual condition. The military pilots observed the airplane depart controlled flight and spiral to the ground, impacting an open field. All occupants on board the airplane, the captain, first officer, and four passengers, were killed, and the airplane was destroyed. The National Transportation Safety Board determined the probable cause of this accident was incapacitation of the flight crewmembers because of their failure to receive supplemental oxygen following a loss of cabin pressurization, for undetermined reasons.

The airplane included an oxygen system that provided emergency oxygen for the flight crew and passengers comprising of a single oxygen bottle, an oxygen bottle pressure regulator with a shutoff valve, an oxygen pressure gauge, an overboard discharge relief valve and indicator, flight crew mask quick disconnect valves, flight crew masks, a manual passenger shutoff valve, an oxygen aneroid valve, an oxygen aneroid bypass shutoff valve, passenger oxygen actuator lanyard valves, and passenger masks. Oxygen was available to the flight crew at all times during the flight when the oxygen bottle pressure regulator shutoff valve is open, as it was at the time of impact.

If the pilots had received supplemental oxygen from the airplane's emergency oxygen system, they likely would have properly responded to the depressurization by descending the airplane to a safe altitude. Therefore, it appears that the partial pressure of oxygen in the cabin after the depressurization was insufficient for the flight crew to maintain consciousness and that the flight crewmembers did not receive any, or adequate, supplemental oxygen.

What is needed then, is a system, method, and apparatus for supplying a locally oxygen-rich environment during depressurization allowing flight crewmembers sufficient time to respond and to take corrective measures including the donning of an oxygen mask.

SUMMARY OF THE INVENTION

The present invention comprises a method, a system, and an oxygen delivery boomlet are configured to provide an additional partial pressure of oxygen to an aviator. The boomlet includes a conduit configured to receive an oxygen flow from a positive pressure oxygen source. A nozzle is in communicative connection with the conduit such that the oxygen flow the conduit receives is conducted to the nozzle. The nozzle is configured to direct the conducted flow of oxygen to an interpalatine region of the aviator. The boomlet is optionally configured for attachment to a microphone boom. Alternatively, the conduit is a void the microphone boom defines. The nozzle may optionally be attached to the microphone boom.

In accordance with further aspects of the invention, the positive pressure oxygen source includes a regulator. In an embodiment, the regulator includes an on/off valve.

In accordance with other aspects of the invention, the regulator is further configured to include a switch, the automated switch being configured to receive positive pressure from a first oxygen source in a first position and from a second oxygen source in a second position. The switch is, optionally, further configured to select the first position based upon the presence of a positive pressure from the first oxygen source or the second position based upon the presence of a positive pressure from the second oxygen source.

In accordance with still further aspects of the invention, the nozzle directs the flow to an interpalatine region, that region extending from generally an aviator's nostrils and extending to generally the aviator's mouth. Embodiments of the invention direct the oxygen flow to the nostrils particularly while other embodiments direct the oxygen flow to the interpalatine region generally midway between the nostrils and the mouth.

As will be readily appreciated from the foregoing summary, the invention provides a system, method, and apparatus for supplying a locally oxygen-rich environment during depressurization allowing flight crewmembers sufficient time to respond and to take corrective measures including the donning of an oxygen mask.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention comprises a method, a system, and an oxygen delivery boomlet are configured to provide an additional partial pressure of oxygen to an aviator. The boomlet includes a conduit configured to receive an oxygen flow from a positive pressure oxygen source. A nozzle is in communicative connection with the conduit such that the oxygen flow the conduit receives is conducted to the nozzle. The nozzle is configured to direct the conducted flow of oxygen to an interpalatine region of the aviator. The boomlet is configured for attachment to a microphone boom.

Referring toFIG. 1, a boomlet10is attached to a headset assembly27. The headset assembly27is of the sort commonly used by an aviator6to maintain radio contact with air traffic control (ATC) functions while engaged in piloting an aircraft. Such a headset assembly27generally includes a microphone boom assembly20, itself consisting of a microphone21on a microphone boom24. The microphone boom24is used to place the microphone21in advantageous proximity to a mouth7of the aviator6in order to capture pressure variations that are the sound of uttered words.

Extending between the mouth7and nostrils8, an aviator6has an interpalatine region9. The interpalatine region includes the nostrils8and the mouth at opposed boundaries. It is advantageous to direct an oxygen flow17at this interpalatine region9in order to increase the oxygen concentration the aviator6is capable of inhaling at times of rapid cabin depressurization.

The boomlet10is configured to direct oxygen at the interpalatine region9by directing the oxygen flow17through a nozzle11, the nozzle11being configured to vent oxygen under pressure to generate and direct the oxygen flow17. The oxygen under pressure is provided the nozzle11through a conduit14that, itself, is connected both to the nozzle11and at an opposed end to an airplane oxygen system.

The airplane oxygen system provides emergency oxygen for the aviator6. Generally oxygen is available to the aviator6automatically above 14,000±750 feet cabin altitude or manually (at any cabin altitude) by opening the normally closed oxygen aneroid bypass shutoff valve, which is located on an instrument sidewall (not shown). The boomlet10provides the oxygen without requiring the aviator6to don a mask. In the course of an unplanned or undetected loss of cabin pressure, the aviator6will have a sufficient oxygen flow17to make such maneuvers as are necessary to respond to the loss of cabin pressure without having to interrupt the maneuvers to don the mask.

By way of nonlimiting example, the boomlet10is shown attached to the microphone boom24advantageously providing a mounting site for the nozzle11allowing the directing of the oxygen flow17at the interpalatine region9. While so attaching the boomlet10to the microphone boom24is a means of properly positioning the nozzle11, another embodiment includes the incorporation of the boomlet10into the microphone boom24. A void that the microphone boom24defines within its length suitable serves as a portion of the conduit14thereby advantageously fixing a spatial relationship between the nozzle11and the microphone21. The spatial relationship is chosen to prevent the oxygen flow from obscuring sounds the microphone is configured to capture.

In another embodiment, the nozzle11is configured to be a nasal cannula inserted into or in close proximity to the nostrils8. Advantageously, a nasal cannula nozzle11provides further concentration of oxygen in the ambient gasses available to the nostrils8of the aviator6. By way of non-limiting example, the nasal cannula nozzle11might optionally include a valve opening the cannula nozzle11to the ambient atmosphere when no relative oxygen pressure is supplied by the conduit14but closing the cannula to the ambient atmosphere when the conduit14supplies oxygen pressure to vent generating an oxygen flow17into the nostrils8.

Referring toFIG. 2, the boomlet10, including the conduit14is detachably attached to an instrument panel quick release30. While not limited to placement on the instrument panel, the instrument panel quick release30as used herein refers to any suitable quick release of the sort used to allow the aviator6to join the boomlet10by means of its conduit14to the oxygen supply system of an aircraft. Quick releases are known to the aviation oxygen industry and readily obtained from suppliers. The instrument panel quick release30is not necessary for any embodiment of the invention but, rather, is provided for the convenience of the aviator6.

A regulator40is provided to step down oxygen pressure to provide a breathable oxygen flow17. By way of explanation, a typical oxygen bottle64has a storage capacity of 38 cubic feet at 1,800 pounds per square inch (psi). Oxygen pressure for the flight crew and passenger distribution systems is reduced to 70 psi via the oxygen bottle pressure regulator/shutoff valve that is mounted directly on the oxygen bottle64and is included therein inFIG. 2for purposes of clarity. The oxygen bottle64and attached oxygen bottle pressure regulator/shutoff valve are generally located in the nose cone of the airplane and are inaccessible to the flight crew during flight and the 70 psi pressure lines convey oxygen to the aviator at an advantageous flow rate. Nonetheless, venting a 70 psi pressure will result in too great a volume at too great a velocity to allow the aviator6to comfortably breathe. The regulator40further steps down the pressure from the 70 psi pressure lines. Additionally, the regulator40allows for a second oxygen supply, in the shown embodiment inFIG. 2, in this case, oxygen supplied by an oxygen generator67.

Referring toFIG. 3, the regulator40in one nonlimiting embodiment is configured to allow redundancy in the provision of oxygen and includes an on/off valve42; a manifold pressure regulator44; a first pressure sensing valve46; and a second pressure sensing valve48. The pressure sensing valves46,48, are configured to prevent contamination or escape of the oxygen flow17while allowing oxygen from a first oxygen supply54, such as the oxygen bottle64(FIG. 2), and from a second oxygen supply57, such as the oxygen generator67(FIG. 2) to be selectably provided to the on/off valve42to supply the boomlet10(FIGS. 1,2). Each of the first and second pressure sensing valves46,48tests continually for the presence of a relative oxygen pressure and if it is absent, shuts down the pressure sensing valves46,48according to that absence assuring a ready source of relative oxygen pressure.

At the manifold pressure regulator44the flows are selectably chosen to give a reliable oxygen flow17(FIG. 1) at the nozzle11. This can be by any of several means. Pneumatic switching, electronic switching, or a combination of electronic and pneumatic means will selectably choose the preferred source. Generally speaking, for example, exhausting oxygen from the oxygen bottle64(FIG. 2) is less expensive than activating and exhausting the oxygen from the oxygen generator67(FIG. 2). The switching within the manifold regulator44will accommodate the appropriate and reliable supply of an oxygen flow17at the nozzle11.

Commercially available regulators include the on/off valve42, such as the Puritan Bennett™ part number 112145A, having three positions (NORMAL, 100%, and EMERGENCY) and incorporates a dilution aneroid that will progressively shut off the diluter (cabin) port upon rising cabin altitudes, thereby supplying 100 percent oxygen at cabin altitudes above 33,000 feet. When the selector lever is in the EMERGENCY position, the regulator supplies 100 percent oxygen, regardless of altitude, at a positive pressure of approximately 0.15 psi. This regulator will also automatically supply oxygen under positive pressure (approximately 130 liters per minute at 0.5 psi) at cabin altitudes above 39,000 feet, regardless of the regulator-selected mode. In this non-limiting embodiment of the invention, the on/off valve is similarly operative.

While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. For example, the conduit14need not be attached to the microphone boom24so long as the nozzle11is suitably configured to provide the oxygen flow17at the interpalatine region9. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.