USO0RE41381E

(19) United States (12) Reissued Patent

(10) Patent Number:

Stabile et a]. (54)

(45) Date of Reissued Patent:

METHOD OF CALCULATING OXYGEN REQUIRED AND SYSTEM FOR

“EASy Flight Deck Improves HoW Pilots Manage Aircraft’s Systems and its Flight”, Dassault Falcon Aircraft, Press Release, Feb. 22, 2005, pp. 143*

Inventors: James R. Stabile, c/o Aeronautical Data Systems, Inc., PO. Box 63, StillWater, NJ (Us) 07875; William L- Mack, 0/0 Aeronautical Data Systems, Inc, P0 Box 63, StillWater, NJ (US) 07875

(Continued)

Primary ExamineriRob SWiatek (74) Attorney, A gem, 0r FirmiBradley N. Ruben

(57)

(21) APP1~ NOJ 10/460,704 22

(

)

13-1 (12 16

J

Patent NO;

6,244,540

Issued,

Jun_ 12 2001

pressurized oxygen supply Which feeds oxygen into the inte rior of the plane When it ?ies at high cabin altitudes, the system indicating the changing status of the supply as oxy gen is drained therefrom. The system includes a pressure transducer coupled to the supply and means associated With the transducer to determine the lapse rate at Which the pres

Appl_ No; Filed,

09/630,212 Aug 1, 2000

sure of the supply is reduced as oxygen is drained therefrom to yield a ?rst signal representing this pressure lapse rate,

Related US Patent Documents

and to concurrently determine the lapse rate at Which the number of liters of oxygen in the supply is reduced as oxy gen is drained therefrom to yield a second signal represent ing the liter lapse rate. These signals are applied to a micro processor in Whose data base is entered the total oxygen

U.S. Applications: (63)

Continuation-in-part of application No. 09/080,187, ?led on May 18, 1998, now abandoned.

(51)

(52) (58)

ABSTRACT

A system useable in a jet aircraft having installed therein a

_ 12 2003 ml ’

Reissue of,

(64)

Jun. 22, 2010

OTHER PUBLICATIONS

MONITORING OXYGEN SUPPLY AND/OR CALCULATING FLIGHT LEVEL AFTER EMERGENCY CABIN DECOMPRESSION (76)

US RE41,381 E

Int. Cl. B64D 13/02

US. Cl. ................................... .. 244/118.5; 244/194 Field of Classi?cation Search .............. .. 244/76 R,

inventory of the supply and the oxygen demand of the plane in Which the supply is installed. When oxygen is being drained from the supply, the microprocessor calculates and reads out the prevailing supply pressure, the number of liters remaining in the supply, and the time in hours and minutes

244/1185, 175, 194, 78, 118.1, 136; 701/99 See application ?le for complete search history.

remaining before the supply is exhausted based on the cur rent rate of oxygen consumption.

(56)

(2006.01)

References Cited

The invention provides both a method for calculating the

U.S. PATENT DOCUMENTS

oxygen required, as Well as a real time monitoring and cal

2,894,193 A

culating system for emergency conditions. The invention is applicable to any pressurized gas system, such as for divers,

7/1959 Reitman

compressed gas cooking or vehicles, therapeutic oxygen,

(Continued)

and the like.

FOREIGN PATENT DOCUMENTS EP GB

0 324 259 694750

7/1989 7/1953

17 Claims, 15 Drawing Sheets

PRESSURE'TO-LITERS MODULE

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US RE41,381 E Page 2

US. PATENT DOCUMENTS

* 11/2000 McElreath et a1. ........ .. 340/970

6,161,063 A * 12/2000 6,188,937 B1 * 2/2001

*

3,842,720 A

* 10/1974 Herr .......................... .. 454/71

6,244,540 B1 *

6/2001

stabile et a1,

3,851,304 A 3,864,025 A

* 11/1974 * 2/1975

6,507,776 B1 *

1/2003

FOX,111 ..................... .. 701/11

3,922,149 A

* 11/1975 Ruder et a1.

Picardat .................... .. 340/980 Picardat .................... .. 359/630

Deck Tools for distributed air ground decision mak_

2?“ et al'l



6720/

me et a ' I """"""" "

5,086,396 A

*

2/1992

WarusZeWskl, Jr.

5,346,778 A

*

9/1994

Ewan et a1. ..... ..

*

5,544,842 A *

5,574,647 A

ing in future ATM”, Human Information Process Research Branch, (no date), Battiste, V. & Johnson W., pp. 1 of 1.*

....... .. 701/221



429/19



5,367,901 A * 11/1994 Petersen .................. .. 73/64.45 5,516,330 A

244/118,5

OTHER PUBLICATIONS

9/1976 W111121II1S ............. ..

i * ’

Culbertson --------------- -- 137/811

Deker .......................... .. 701/4 Sherryetal. ................ .. 701/14

2,974,673 A

3,981,300 A :

3/1961

6,154,151 A

5/1996 Dechow et a1. ............. .. 454/74

8/1996 Smith et a1. ............... .. 244/1 R

11/1996 Liden

G1ass Cockp1t- 1.,, ,AnsWers.com, (no date), pp.d1*3. * hn 1 . h . ,, Tee

0 OgYF 1eS*H1g °nB°e1ng737 ssan YAngerS>PP

155061252003

“Integrated Human Centered Systems Approach to the

Development of Advanced Air Tra?ic Management Sys

5,590,852 A *

1/1997 Olson .................... .. 244/118.5

terns”;

5,606,505 A

2/1997

atmeseminare97.eurocontro1.fr/hansman.htm.*

*

Smith et a1~ -

~~~~ ~~ 701/99

5,791,982 A

*

8/1998 Curry et a1. ................. .. 454/74

5,809,999 A

*

9/1998

5,934,083 A

*

8/1999 Scherer et a1. ............... .. 62/79

Hansman,

John;

May

5,

1998,

The Boeing 7571200 (WWWbOeingCOm) pp 1148

Lang ................... .. 128/200.24

* cited by examiner

http://

US. Patent

Jun. 22, 2010

Sheet 1 or 15

US RE41,381 E

FIG. 1

Fiéféikééihiédlbé' 1/11 ‘- - - - — - ~ ¢ -

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12

‘ ['10 OXYGEN my

K .T PRESSURE TRANSDUCER __,H

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53/ L1/1 22\ cu ROM

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'11

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US. Patent

Jun. 22, 2010

Sheet 2 or 15

US RE41,381 E

FIG. 2 PRESSURE TEMPERATURE CONVERSION CHART SETTLEO TEMPERATURE

BOTTLE PRESSURE

NTPO

17

CONDITION: THIS TABLE IS BASED ON THE OXYGEN SYSTEH BEING FILLEO TO 1850 psi AT AN AMBIENT BOTTLE TEMPERATURE OF 70 DEGREES FAHRENHEIT NTPO (NATIONAL TEWERATURE PRESSURE DRY]

US. Patent

Jun. 22, 2010

Sheet 3 0f 15

US RE41,381 E

FIG . 3 A

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247

493

740

986

1233

1480

1720

1973

6000

225

450

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115

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1575

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210

420

830

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1250

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481

614

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264

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528

660

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US. Patent

Jun. 22, 2010

Sheet 4 0f 15

US RE41,381 E

FIG. 4 OXYGEN INVENTORY

TWO 115 CUBIC FOOT BOTTLES PRESSURE (PSI)

CAPACITY (LITERS)

1850 1300 1150 1100 1650 1600 1550 1500 1450 1400 1350 1300 1250 1200 1150

6509 6333 6151 5931 5305 5629 5453 5213 5102 4926 4150 4514 .4393 4222 4046

1100

3310 -

1050 1000 950 900 350

3694 3513 3342 3161 2991

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2815

22111 2111 1935 1159 ,

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350

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250

830

200-

104

US. Patent

Jun. 22, 2010

Sheet 5 0f 15

FIG. 5A J\

OXYGEN DURATION FLIGHT LEVEL 250

NTPD

LTRS

CREW SYSTEM

1050 1000 1700 1500 1500 1400 1300 1200 1100

1415 1377 1300 1224 1147 1071 994 91B 041

2:41 2:35 2:20 2: 19 2: 10 2:01 1:53 1: 44 1:35

1000

755 5

1:27

900

600

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612

1:09

700

535

1:00

600

459

:52

500 400 300

982 306 229

:43 :34 :26

200

153

: 17

CREW

2

REDUCTION TO 02 INVENTORY ELIHB T0 FL. 250 311 REDUCTION

US RE41,381 E

US. Patent

Jun. 22, 2010

Sheet 6 0f 15

FIG. 5B /\

OXYGEN DURATION FLIGHT LEVEL 200

NTPD

LIBS

CHEN SYSTEM

1950 1900 1700 1600 1500 1400 1300 1200 1100 1000 900 000 700 500 500 400 300 200

1415 1377 1300 1224 1147 1071 994 918 B41 755 500 512 535 459 382 305 229 153

3:30 3:32 3:20 3:00 2:57 2:45 2:33 2:21 2:09 1:50 1:45 1:34 1:22 1: 10 :59 .47 :35 23

CREW

2

REDUCTION TO 02 INVENTORY CLINB TO FL. 200 290 REDUCTION

US RE41,381 E

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Jun. 22, 2010

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US RE41,381 E 1

2

METHOD OF CALCULATING OXYGEN

REQUIRED AND SYSTEM FOR

indicator which informs the pilot in the cockpit of the pre vailing pressure of the supply; some systems also compen

MONITORING OXYGEN SUPPLY AND/OR CALCULATING FLIGHT LEVEL AFTER EMERGENCY CABIN DECOMPRESSION

sate for the temperature of the oxygen canister. If when the ?ight starts and there is 1850 psi in the canister, and some time later there the reading is 1300 psi, the pilot knows there is less oxygen but does not have a clear indication of the

Matter enclosed in heavy brackets [ ] appears in the original patent but forms no part of this reissue speci?ca

duration of oxygen remaining. What the pressure gauge does

not inform the pilot, yet is important that he know, is exactly

tion; matter printed in italics indicates the additions made by reissue. This application is a continuation in part of Ser. No.

how much time remains before the oxygen supply is insu?i cient to meet the oxygen demand of the particular ?ight. This demand depends not only on the siZe of the plane and its passenger capacity, but on the actual number of passengers and crew in the ?ight, and on the type of oxygen masks being used. For example, those used in emergencies when a

09/080,187, ?led May 18, 1998 abandoned. BACKGROUND OF THE INVENTION 1. Field of Invention This invention relates generally to a system associated with a gas supply which is adapted to monitor the supply and

cabin depressuriZes (the yellow-colored drop down masks) are activated by pulling on the mask and the ?ow is through a ?xed valve; thus, the ?ow through the mask is a function solely of the differential between the oxygen pressure in the manifold and ambient pressure (so more ?ows as the altitude

to indicate its status as gas is drained therefrom, and more

particularly, to a system of this type which is installed in a jet aircraft provided with an oxygen supply that is drained only when the plane ?ies at high cabin altitudes, the system in a

20

dynamic displaying the time in hours and minutes that remain before the oxygen is exhausted based on the current rate of oxygen consumption, while in a static mode the sys tem refers to a database to predict duration based on existing

conditions. 2. Status of PriorArt

25

ambient air that is accelerated to the rear of the plane by the 30

planes (other than turboprops) do not function e?iciently at high altitudes where the propulsion medium is relatively tin.. But a jet aircraft depends on jet propulsion created by a force developed in reaction to the ejection of a high-velocity jet of gas. In the combustion chamber of a jet propulsion engine, combustion of the fuel mixture generates expanding gases which are discharged through an ori?ce to form the jet. Hence in a jet plane with a bypass engine, where ambient air is not the propulsion medium, the ambient air impedes the forward motion of the plane unless it is bypassed around the combustion Zone (that is, the air is funnelled through the engine so that the total mass ?ow rate through the engine is increased, and hence more thrust is developed).

ply of oxygen, how much time remains before this supply of oxygen runs out. In fact, each jet plane will have a different

oxygen supply system, with different numbers or con?gura tions of manifolds, and different types of regulator masks for

pilots. 35

Pilots, for each ?ight, are required to plan for suf?cient oxygen on board for a worse case scenario. For example, for

a ?ight from New York City to London, most of the trip is over the Atlantic ocean, and the “worst case” is a depressur 40

iZation at the Equal Time Point (ETP), the point at which the Estimated Time Enroute (ETE) returning to the nearest diversion airport or continuing to the nearest diversion air port is the same. Based on actual wind and weather

When ajet plane ?ies at high altitudes, 35,000 ft (FL 350) for commercial jets and 41,000 ft. (FL 410), the FAA regu

(that is, the oxygen is forced under pressure through the mask into the pilot’s lungs, and he must force out his exhalation). Accordingly, a pressure gauge reading does not inform the pilot of a jet plane as to the duration of the oxygen supply. It is therefore the present practice to furnish a jet plane pilot with a printed chart or table which he can on occasion consult to determine for a given number of passen gers and crew on a particular ?ight and for a given full sup

In propeller-driven aircraft, the propulsion medium is

action of the rotating propeller. Hence, propeller-driven

increases). One the other hand, pilots’ masks have demand regulators, so that often the pilots must use reverse breathing

45

lations set forth that at least one pilot must have a mask on

conditions, the plane has an effective Ground Speed Return (GSR, returning to the last diversion airport passed) and an effective Ground Speed Continue (GSC, continuing to the nearest diversion airport). ETP can be calculated as

and be breathing oxygen. Further, the FAA regulations pre scribe quantity of oxygen required for the passengers in the cabin and for the ?ight crew in the ?ight deck or cockpit. It is for this reason that all commercial jet aircraft are provided with a pressurized oxygen supply in the form of cylinders or bottles. The magnitude of the supply depends on the siZe of the plane. For example a B-757 jet plane has a single 115 cubic foot oxygen bottle installed thereon which when full has a gas pressure of 1850 psi. On the other hand a B-747 plane has seven such bottles installed thereon. And on a

50

where D is the distance between the GSR diversion airport and the GSC diversion airport (typically measured in nauti cal miles). The ETP can usually be derived from a comput

eriZed ?ight plan. Fortunately, the problem of sudden cabin 55

depressuriZation, to extent of oxygen requirements, is less problematic in a commercial airliner. Oxygen is only

required, by FAA regulations, for ?ight levels above 10,000 ft. (FL 100). Commercial airliners typically carry suf?cient

Falcon 50 jet plane there is only one 76.6 cubic foot bottle of oxygen which when the bottle is full has a pressure of 1850

fuel so that, after a catastrophic depressurization, they can

psi. Oxygen canisters (bottles) for aviation are typically cited in pounds per square inch (gauge) of pressure (“psi”), at NTPD (National Temperature Pressure Dry), while oxy

make an emergency descent to 10,000 ft. and continue or 60

gen ?ows for breathing are typically measured volumetrically, usually liters per minute. The oxygen in the

return at that level, avoiding the need for oxygen during the entire ETE to the diversion airport.

The real problem occurs with private (e. g., corporate) jets, where the luxury of uploading su?icient fuel to ?y at 10,000

canister is supplied to one or more manifolds from where it

The present practice in a jet plane is to provide the oxygen

ft. to a diversion airport is lacking. If there is a sudden depressuriZation and after emergency descent to FL 100 there is su?icient fuel to travel to a diversion airport at FL

supply installed therein with a pressure gauge coupled to an

100, the problem is averted. Otherwise, the plane must climb

is distributed to the pilots, crew, and passengers.

65

US RE41,381 E 4

3 to increase the Speci?c Range (SR). Accordingly, the

Still a further object of the invention is to provide a system

pilot(s) must calculate, based on the performance charts for the speci?c aircraft being ?own, the minimum altitude at

by Which, after an emergency or catastrophic depressuriza tion of a jet cabin, a WindoW of operation is provided to the pilot(s) based on fuel, ?ight level, and oxygen stores, to reach the nearest diversion airport. In various embodiments, the pilot(s) can be provided With a readout of suitable param

Which the SR is su?icient to reach the diversion airport. The

higher the altitude, the farther the SR; hoWever, fuel usage increases slightly as altitude increases. Most importantly, at FL greater than 100, oxygen is required for the creW and passengers. Also, Wind speed varies as a function of altitude, so a higher altitude may encounter a higher head (or tail) Wind speed. Accordingly, in an emergency situation there is a tradeoff among fuel available, altitude (SR), and oxygen available. Unfortunately, determining the altitude for a su?i

eters to continue the ?ight, and/or can be provided With a

graphical display based on the foregoing parameters. Brie?y stated, these objects are attained in a system use able in a jet aircraft having installed therein a pressurized oxygen supply Which feeds oxygen into the interior of the

plane When it ?ies at high cabin altitudes, the system indicat ing the changing status of the supply as oxygen is drained

cient SR and the oxygen available is an iterative process, and

the time for these calculations is not during a catastrophic depressurization in the middle of the night over Water.

therefrom. The system includes a pressure transducer coupled to the supply and means associated With the trans ducer to determine the lapse rate at Which the pressure of the supply is reduced as oxygen is drained therefrom to yield a

Additionally, after the decompression, the pilot(s) must determine an operating WindoW to ?y to one or tWo pre

planned diversion airports (or, perhaps, an unplanned diver sion airport); While the pilot(s) regains control of the aircraft and stabilizes the situation, the jet is still continuing on its

?ight path, and so is using fuel, oxygen, and changing the

20

distances betWeen it and the diversion airports, further

effecting calculations of the operating WindoW. Ruder, US. Pat. No. 3,922,149, is directed to eliminating tanks of stored oxygen by providing an oxygen enrichment system that uses a molecular sieve that absorbs oxygen the

25

least, and hence enriches the oxygen content of the sieve

vailing supply pressure, the number of liters remaining in the supply, and the time in hours and minutes remaining before

e?iuent stream.

Bishaf, US. Pat. No. 3,875,801 Which discloses a pressur ized gas tank to supply oxygen to a scuba diver, the gas being depleted at a variable rate. In Bishaf, the amount of gas remaining in the tank is displayed “in terms of the amount of time until depletion.” In the Bishaf system, a transducer

placed Within the gas tank produces an electrical signal indicative of the instantaneous gas pressure. The signal is applied to an integrated circuit chip What develops a signal proportional to, the rate of change of the instantaneous pres

30

35

40

Weapons in a submarine, to assure proper ejection velocity at

the accompanying draWings, Wherein: 50

FIG. 1 is a block diagram of a pressure monitoring,

temperature-compensated system for determining oxygen lapse rate and time remaining; FIG. 2 is a table shoWing pressure correction of tempera ture for oxygen (gas);

in connection With an oxygen supply installed on a jet air 55

FIG. 3 is a table shoWing oxygen consumption for a creW

member (pilot) in a Challenger model CL601-3A jet at the effective cabin altitude shoWn, pursuant to FAA regulations and a table depicting therapeutic oxygen compensation in liters having a higher than normal ?oWrate;

at high altitudes. The system indicates the time remaining before the supply is depleted Whereby the pilot has time to

60

FIG. 4 is a table shoWing the oxygen capacity in liters as a

function of NTPD pressure of tWo 115 ft.3 oxygen canisters; FIGS. 5A and 5B are tables shoWing the duration of oxy

the above type in Which on the ?ight deck of the jet plane there are displayed the prevailing pressure of oxygen in the supply, the number of liters of oxygen remaining in the

gen usable by a creW of tWo in a Challenger model CL601 3A jet as a function of NTPD or liters at FL 250 (5A) and FL

supply, and the time remaining before the supply is depleted. Yet another object of the invention is to provide a comput erized system of the above type Which is reliable in opera tion and affords correct readings.

For a better understanding of the invention as Well as other

objects and further features thereof, reference is made to the folloWing detailed description to be read in conjunction With

supply is depleted. More particularly, an object of this inven

take the plane to a loWer altitude at Which there is no need for oxygen. Also an object of the invention is to provide a system of

plies used by Welders, air/oxygen tanks used by divers (in Which depth monitoring (analogous to SR) and depressur

BRIEF DESCRIPTION OF DRAWINGS 45

tion is to provide a system of the above type Which is useable craft to feed oxygen into the interior of the plane When it ?ies

particular application, for it is applicable to any pressurized gas supply Whose operator must monitor the supply and knoW hoW much time remains before the supply is depleted. Thus oxygen supplies used in hospitals and helium supplies

ization time (analogous to fuel) are input to the system), and the like systems.

all depths at Which the submarine may be operating. Erickson, US. Pat. No. 4,408,484, discloses a tempera ture compensated gauge for pressurized gas, especially for SUMMARY OF THE INVENTION In vieW of the foregoing one object of this invention is to provide, in association With a supply of pressurized gas, a system adapted to monitor the drain of the gas from the supply and to indicate the time Which remains before the

temperature. The fuel remaining and the distances to the diversion airports can be included in the calculations.

used in dental of?ces can be monitored by a system in accor dance With the invention, as Well as oxygen-acetylene sup

Schmitt, US. Pat. No. 4,485,669, is directed to a device

natural gas fuel for vehicles or homes.

the supply is exhausted based on the current rate of oxygen consumption. The amount of oxygen can be corrected for

The system described herein is by no means limited to this

sure.

for determining the timely delivery of compressed gas from compressed gas canisters, and especially for the ejection of

?rst signal representing this pressure lapse rate, and to con currently determine the lapse rate at Which the number of liters of oxygen in the supply is reduced as oxygen is drained therefrom to yield a second signal representing the liters lapse rate. These signals are applied to a microprocessor in Whose data base is entered the total oxygen inventory of the supply and the oxygen demand on the plane in Which the supply is installed. When oxygen is being drained from the supply, the microprocessor calculates and reads out the pre

65

200 (5B); FIGS. 6A and 6B are tables shoWing the duration of oxy gen usable by a given number of passengers in a Challenger

US RE41,381 E 6

5

During an unevenful ?ight, the oxygen requirement will

model CL60l-3A jet as a function of NTPD or liters at FL

250 (6A) and FL 200 (6B);

be the sum of that required above FL 410 (as shown in FIG.

FIGS. 7A and 7B are tables showing the performance curves for General Electric CF34-3A engines at FL 250 (7A) an FL 200 (7B);

ing oxygen during the entire trip), and any needed for an

3), any therapeutic oxygen required (i.e., a passenger requir emergency descent to FL 100 (at which level oxygen is not required; see the bottoms of FIGS. 5A/5B and 6A/ 6B, which include the emergency descent oxygen for the listed passen

FIG. 8 is a graphical display, such as on a computer readout, of ETPs over the Atlantic ocean at various ?ight

gers plus a crew of two, and are discussed in more detail

levels (FLs);

below). This is then the minimum amount of oxygen that should be carried onboard. For example, a ?ight having two pilots and an effective cabin pressure of 7000 ft. for 3 hrs, no passengers on therapeutic oxygen, and six passengers,

FIG. 9 is a graphical display, such as on a computer readout, of ETP as a function of cardinal altitude; FIG. 10 is a graphical display, such as on a computer readout, of the ETP in FIG. 9 plus fuel duration as a function

would require about 1260 liters (FIG. 3) plus more than 1069 liters (FIG. 6A) of oxygen, so a safe estimate would be about 2330 liters of oxygen. Additionally, the pilot must plan for an emergency at the

of time and altitude; FIG. 11 is graphical display, such as on a computer

readout, of the display shown in FIG. 10 with the addition of

ETP. The ?ight plan provides (and the pilot can always deter mine later, prior to departure) the actual wind conditions, and typically provides the ETP (or it can be derived) and the

oxygen duration as a function of time and altitude, and

including an operating window with a suggested altitude for conservation of fuel and oxygen resources; and FIG. 12 is a graphical display, such as on a computer readout, of a display analogus to that shown in FIG. 11 where there is insuf?cient oxygen to ?y above FL 100 and suf?cient fuel to ?y at FL 100 to a diversion airport. DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

20

25

understand how a pilot should determine, the total amount of

In reality, after an emergency descent, the jet will climb to 30

two in Challenger model CL60l-3A jet as a function of NTPD or liters at FL 250 (5A) and FL 200 (5B). FIGS. 6A and 6B are tables showing the duration of oxygen usable by a given number of passengers in a Challenger model CL60l 3A jet as a function of NTPD or liters at FL 250 (6A) and FL

then not always assuming a worst case emergency scenario.

Prior to departing, the pilot must ?rst calculate the amount FIG. 2 depicts a pressure-temperature conversion chart based on an oxygen system ?lled to 1850 psi at 21° C. (700 E), which is the normal assumed temperature, although a ?ight from the tropics or the desert may typically be at 90° F.

an altitude suf?cient to provide an SR effective to reach a

diversion airport. The charts shown in FIGS. 5A and 5B are tables showing the duration of oxygen usable by a crew of

oxygen that should be carried on board, including planning for an emergency/ catastrophic cabin decompression, to have a suitable operating window (fuel, SR, and oxygen) to safely divert to an alternate airport. The following procedure is not necessarily done, and does form in integral part of this invention because typically the pilot only estimates the amount of oxygen that should be required for the ?ight, and

of oxygen that would normally be required for the ?ight.

fuel remaining at the ETP and the known time (via ETP) to reach a diversion airport, the pilot must determine the alti tude at which the jet must ?y to have an SR su?icient to reach either diversion airport at the ETP. Knowing the alti tude required to have a su?icient SR to reach the diversion airport, the oxygen requirement will be de?ned. This oxygen requirement should then be added to that determined for an

unevenful ?ight.

Manual System Before addressing the present invention, it is useful to

amount of fuel remaining at the ETP. Based on the amount of

40

200 (6B); recall this pilots’ masks are regulated whereas passengers’ emergency masks are unregulated, ?xed valve devices. Thus, if the ?ight plan estimates that the ETP is 1:30 hrs. and the pilot knows that if there were an emergency at the ETP he would have to ?y at FL 250 to reach a diversion

on average and one near the artic circle may be more likely

airport, the additional oxygen would be the 770 liters shown in FIG. 5A (note that interpolation must be done from the time of l :30 to determine the liters required), plus 1549 liters from FIG. 6A (again interpolating from the time of 1:30

at 40° on average.

using the column for six passengers).

45

As noted above, FAR (federal aviation regulations) require that a commercial ?ight above 410 EL have a pilot breathing oxygen at all times. At ?ight levels above FL 100, each plane is designed to have an effective cabin altitude somewhere between FL 50 and FL 100 regardless of the altitude. FIG. 3 is a table showing the oxygen comsumption in liters per hour for a crew member (pilot) in a Challenger model CL60l-3A jet at a given effective cabin altitude. Also shown in FIG. 3 is a therapeutic oxygen table, and this par ticular aircraft does not have a therapeutic oxygen outlet (which is a connection taken typically taken from the mani fold for the passenger emergency oxygen and supplied on a demand basis at a rate typically greater than for the passen

Thus, the total calculated oxygen is 2330 (normal opera tions plus emergency descent) plus 770 plus 1549, for a total 50

of 4649 liters. Also, under 200 psi there is no useful amount of oxygen supplied, so at 70° F. an additional 350 liters of

oxygen must be added. Hence, the total oxygen required,

including that for “expected” emergencies is about 5000 55

liters. Looking at FIG. 4, this would require two 115 cu. ft. canisters at about 1421 psi. After a real emergency while in ?ight, the crew would have to manually redo the calculations based on an ETP

where the emergency actually occurred. If there is a sole 60

pilot, this can present signi?cant problems, having to both control the jet and make iterative calculations. For example,

ger emergency oxygen). Typically, the effective cabin alti

FIGS. 7A and 7B are tables showing the performance curves

tude is about 5000 to 8500 feet, and more typically at 7000

for General Electric CF34-3A engines at FL 250 (7A) and FL 200 (7B). In particular, on the grid, the distance (SR) in nautical miles is given; on the left abscissa is the fuel required (in pounds) and on the right abscissa is the ETE in hours. On the graph are four lines, the engine performance

to 8000 feet; the pilot will (should) know the manufacturer’s

speci?cation for that particular plane. FIG. 4 is a table showing the oxygen capacity in liters as a function of NTPD pressure of two 115 ft.3 oxygen canisters, which should be corrected by the temperature in FIG. 2.

65

based on different wind conditions; from the left a 100 knot

Method of calculating oxygen required and system for monitoring ...

Jun 22, 2010 - For example, for a ?ight from New York City to London, most of the trip is over the Atlantic ocean, and the “worst case” is a depressur. iZation at the Equal Time Point (ETP), the point at which the. Estimated Time Enroute (ETE) returning to the nearest diversion airport or continuing to the nearest diversion air.

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