MH Pulse-Demand MH EDS O2D1-2G User manual

Single Person
Electronic Digital Pulse-DemandTM
Aviation Oxygen Delivery System
MH EDS O2D1-2G
INSTRUCTION MANUAL
800-468-8185 • 541-923-4100 • Fax: [phone] • www.MHoxygen.com • 2244 SE Airport Way, Suite 100 • Redmond OR 97756-7537
Patent # 6,220,244
Other Patents Pending
CONTENTS
INTRODUCTION ....................................2
FEATURES .............................................2
BASIC SAFETY ......................................2
GETTING STARTED ...............................3
INSERTING & REMOVING
THE BATTERIES .....................................4
REMOVING THE TUBING ......................4
STORING THE O2D1 .............................4
MOUNTING THE O2D1 .........................4
MODE CONTROL SWITCH SETTINGS
AND MODES OF OPERATION ..............5
ALARMS AND ALERTS .........................6
USING THE O2D1-2G WITH A
THIRD PARTY REGULATOR ..................6
TROUBLE-SHOOTING ...........................7
WARRANTY ..........................................7
MAINTENANCE QUESTIONS ................8
WHAT EVERY PILOT SHOULD
KNOW ABOUT OXYGEN ......................9
AUTO COMPENSATION ......................11
O2D1-2G SPECIFICATIONS ................12
Thank you for purchasing the MH EDS O2D1-2G
Pulse-Demand Oxygen Controller. The MH EDS
O2D1-2G (O2D1) is patented oxygen control tech-
nology that allows you and your co-pilot to fly with
safety and comfort, knowing it will automatically
give the oxygen required at the various altitudes.
THE EDS O2D1-2G IS DESIGNED FOR
EASY OPERATION, PLEASE CAREFULLY
READ THIS INSTRUCTION MANUAL
BEFORE USE.
5MD10-0002-00$b 2015-10-01
Proudly Made in the USA

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2
INTRODUCTION
The patented MH EDS-O2D1-2G (O2D1) is an aviation oxygen delivery device for one person. It is designed to deliver aviation
oxygen in the most efficient, comfortable and convenient way possible. With its user-selectable settings, apnea alarm and small
size, the O2D1 is the most portable and flexible electronic digital oxygen delivery system in the world.
By providing a measured pulse of oxygen at the beginning of each inhalation, the O2D1 automatically supplies the oxygen you
need to stay alert and comfortable while flying. In contrast to constant flow systems that waste oxygen by supplying more than
your body can use, the O2D1 provides a short pulse of oxygen as you inhale, ensuring that your oxygen is used most efficiently.
Efficient oxygen delivery means you can fly farther on a single oxygen refill or save space and weight with a smaller tank. It also
makes it more feasible to enjoy the advantages of oxygen while flying below the altitudes where oxygen is mandated--that can
mean fewer headaches, increased alertness, and feeling less exhausted when you reach your destination. Your actual oxygen usage
will be determined by your breathing rate and physiological needs at altitude.
The programmability of the O2D1 means that, unlike constant-flow oxygen systems, you can “set it and forget it”. By automati-
cally detecting your pressure altitude, the O2D1 can be set to start providing oxygen immediately or at a specified altitude and will
automatically adjust the oxygen flow as your altitude changes. When you’re flying, don’t you have more important things to do
than adjust your oxygen flow during altitude changes?
BASIC SAFETY
Pure oxygen is a highly oxidizing gas and can vigorously accelerate combustion. It can provide a catalyst for spontaneous
combustion resulting in personal injury or death if not used properly and with caution.
FEATURES
Static ports,
DO NOT
COVER
4 mm Red inlet
connects to the
pressure regulator
on the cylinder
• DO NOT use any type of oil or grease on any of the fittings, valves or cylinders.
• DO NOT smoke while in use.
• DO NOT operate near an open flame.
Power On/Off and Rotary
Mode-Selector Switch
Low Battery
Warning Indicator Red/Green LED
Flow Indicator
• Easy-to-use, small size and light weight.
• Incorporates a MIL spec ruggedized easy-to-grip rotary control switch providing improved reliability, increased ease of function
and visibility. This switch also has very positive position detents for excellent tactile feedback making it resistant to changes from
causal rubbing or bumping.
• Automatically adjusts oxygen ow for altitude pressure density.
• Provides reduced oxygen consumption through more efcient oxygen delivery than standard constant-ow systems.
• Rotary Mode-Selector Switch allows automatic altitude enable, Night and Day operations and high ow settings.
• Green/Yellow/Red LED’s indicate oxygen ow, alarm, and status.
• Audible and visible ow-fault alarm informs user of kinked, pinched, or disconnected oxygen lines, obstructed cannula or mask.
• Reduced dry mouth and sinus discomfort compared to constant-ow oxygen systems.
2
6 mm Blue outlet connects
to cannula or face mask

3
GETTING STARTED
The O2D1 is intended to be used with regulators provided by Mountain High. Some third-party oxygen regulators may be used.
See “Using a Third-Party Regulator” page 6 for details. Pilots who intend to fly with the O2D1 are advised to familiarize them-
selves and their passengers with the system prior to using it. Two cannulas and a face mask are included with the O2D1 unit. The
cannula may be used for flight operations up to 18,000 ft. Above 18,000 ft., a face mask should be worn. A compatible face
mask with a built-in microphone is available from Mountain High.
Tote Bag
Face Mask MH EDS-O2D1-2G Unit
Oxygen
Input Tube
AA Batteries (Qty 2)
3M Dual-Lock™ Tape
Cannulas
1 standard, 1 flared tip
Instruction
Manual
O2D1 with cannula
and AA batteries
1. If you have not already done so, fill your cylinder with
Aviation oxygen. (Many FBOs offer this service.)
2. Inventory your system (see photo) and read the front
label on the unit.
3. Read the instructions provided with your cylinder and regu-
lator, attach the regulator to the cylinder and hand tighten
only (DO NOT use a wrench or pliers.
The “O” ring seals the regulator to the
cylinder, and over-tightening will damage
the regulator).
4. Open the battery cover on the back of the O2D1 unit, install
the 2 AA batteries (supplied) and replace the battery cover.
(NOTE: Batteries fit tightly, handle with care.) See
next page for detailed instructions.
5. If you are using the O2D1 with a Mountain High Four-Port
regulator (FPR), locate the oxygen input tube (clear tube with
a short red tube on one end) and insert the Red tube into the
red “Oxygen In” connector on the O2D1 unit until it stops
(approx.1/8 inch). Then connect the other end of the tube to
your regulator. If you are using a MH single port regulator
(XCR), use the red tube that came with the regulator in place
of the tube that came with your O2D1.
6. Insert the Blue end of the cannula or face mask tubing into
the blue “Out” connector on the unit.
(CAUTION: DO NOT pinch the cannula or
face mask tubing when inserting them
into the blue “Out” connectors). Use only
the supplied MH EDS cannula or face mask
as other cannulas or masks will not work
properly with the O2D1. DO NOT lengthen
or shorten the cannula tube.
7. Turn the cylinder valve on.
8. Turn the Rotary Mode-Selector Switch on the O2D1 unit once
clockwise. This will turn the unit on and set it to “N” mode. A
start-up pulse of oxygen, LED light and beeper test will verify
battery power.
9. Don the cannula or face mask (make sure the face mask
seals against the skin) and take a breath. The bright green
LED should illuminate, and a pulse of oxygen should be
delivered. Refer to the card that comes with the cannula
or face mask for details on donning.
10.You are ready to fly.
Comfortable cannula
position, looped over
ears and the tab
pointed down.
3

4
5
4
When not being used, the O2D1 unit, oxygen tubes, cannulas, etc., should be disconnected from the oxygen supply and stored in a
secure manner to ensure that dirt and debris do not enter the inlet and outlet tubes. The supplied tote bag or a zip-top plastic bag
is a good storage container. If the unit is not going to be used for 30 days or more, remove the batteries.
When using the unit for the first time after storage, check the batteries to ensure proper operation.
A set of fresh spare batteries should be part of your pre-flight inventory.
DO NOT store the EDS unit while the inlet is under pressure. Remove all sources of oxygen pressure and secure the
unit to ensure it will not become damaged. If the lines are disconnected they must be covered so that debris, dust or dirt can’t get
in. If the supply line is left hooked to the system, make sure that it is first purged with clean dry air or oxygen before the EDS unit
is connected. If the lines are disconnected they must be covered so that debris, dust or dirt can’t get in.
MOUNTING THE O2D1
You may mount the O2D1 unit to a suitable place using the supplied piece of 3M DUAL LOCK tape. Peel the protective backing off
one of the rectangles to expose the adhesive and apply it to the back of the unit above the thumb indent for the battery door. DO
NOT COVER ANY PART OF THE BATTERY DOOR. When a suitable place to mount the unit has been found, peel off the protec-
tive adhesive backing on the other rectangle and press the adhesive side to the chosen mounting area. Let the adhesive cure
for 12 hours before attempting to remove the two halves of the Dual-Lock from each other, or the
adhesive may pull away from the unit or mounting area.
INSERTING AND REMOVING THE BATTERIES
STORING THE O2D1
INSERTING AND REMOVING THE TUBING
Remove the battery door by pressing down gently on the battery cover flange
then slide the door out and away from the unit. The O2D1 unit uses two (2)
standard AA alkaline batteries. Insert the batteries as shown on the label inside
the battery compartment (they will be a tight fit), then replace the door by slid-
ing the door into place until it snaps in place. Take care when removing and
replacing the batteries as to not damage the batteries and/or connectors.
Recommended Batteries: 2 each 1.5 volt DURACELL ULTRA alkaline
batteries type ‘AA’ or equal quality equivalent.
Battery Life: 100 Hrs. @ ~25° C. @ ~25% R.H. Measured from
mean, assuming fresh DURACELL ULTRA alkaline batteries operating under
normal operating conditions.
NOTE:
Batteries should be replaced annually or when voltage is low.
Lithium batteries are NOT recommended.
To INSERT the tubing, push tubing in until resistance
is felt, then push in a little harder, about another 1/8 inch.
Then give it a gentle tug to make sure it has seated properly.
To REMOVE the tubing, push tubing in slightly,
then push in the connector collar while you pull gently
on the tubing to remove it.
WHEN REMOVING TUBING; DO NOT PULL
ON THE TUBING WITHOUT PUSHING IN THE
COLLAR; IT WILL DAMAGE THE CONNECTOR.
1. Push in the connecting collar
2. Pull the tube
straight back while
pushing in the
connecting collar.
1. Push in the tube
REMOVING
INSERTING
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5
5
The O2D1 unit is controlled by a Rotary Mode-Selector Switch.
A stop inside the selector switch prevents inadvertently turning the unit off in flight.
N MODE: “Night” or “Now”
At this setting the O2D1 will immediately start the standard oxygen
flow, providing pulses of oxygen appropriate for an average healthy
person using a cannula.
Flow start: All altitudes
Use with: Cannula
Flow amount: Standard
Altitude Compensating?: Yes
D MODES: “Day” or “Delayed”
F MODES: “Face Mask”
The D5 setting will cause the O2D1 unit to delay oxygen flow until
it senses a pressure altitude of 5,000 ft. and above. The D10 setting
delays oxygen flow until 10,000 ft. and above. NOTE: When the
barometric pressure is low, it will start operation at a slightly lower
altitude than when the barometric pressure is high.
Mode-Selector Switch as
seen in the ”OFF” setting
NOTE: The N and D modes are designed to provide the amount of oxygen needed by an average size healthy person using a cannula at the given
altitudes; your needs may be different. To determine whether you are receiving enough oxygen in a particular mode you will need to use a pulse
oximeter (available from Mountain High) to determine your blood oxygen saturation (goal is 90-100%) at any given altitude. In all modes, the
O2D1 provides a pulse of oxygen which increases with altitude, i.e., it is altitude compensating.
ROTARY MODE-SELECTOR SWITCH SETTINGS AND MODES OF OPERATION
Mode-Selector
Switch Settings
The O2D1 has three main modes of user
controlled operation:
1. Semi-Automatic (N Mode)
2. Fully-Automatic (D5, D10)
3. Semi-Automatic (F Modes)
NOTE: The F settings are used with the Face Mask or when requiring an increased oxygen
flow with the cannula.
Flow start: All altitudes
Use with: Cannula or face mask
Flow amount: Enriched
Altitude Compensating: Yes
Flow start: D5--5,000 ft., D10--10,000 ft.
Use with: Cannula
Flow amount: Standard
Altitude Compensating?: Yes
5
The F-Mode settings augment the amount of oxygen needed to
compensate for the additional dead-space plenum associated with
face masks. They also can be used with the MH cannula in situations
where more oxygen may be required over the normal ‘N’ and ‘D’ set-
tings. Since F-Mode settings are calibrated for use with the MH Alps
face masks, only use the approved MH EDS or ALPS face mask.
F settings 1 to 2 are for small Alps face masks.
Settings 2 to 3 are for medium sized Alps face masks.
3 to 4 are for large Alps face masks.
F1=
F2=
F3=
F4=
Small Mask
Medium Mask
Large Mask

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6
The O2D1 is equipped with AUDIO-VISUAL ALARMS and ALERTS designed to bring to the user’s
attention potential malfunctions of the unit. Read the following for specifics.
ALARMS AND ALERTS
POWER UP
POWER-UP: Red Light flashing on and off with audio chime for ~ two (2) seconds with each initial power-up with pulse of
O2for about 1/2 second.
O2 DELIVERY or NON-DELIVERY: Normally one flash of the LED Green Light (~1/4 second minimum) will flash for each
pulse of oxygen with a valid inhalation event with properly connected oxygen lines. NOTE: The O2D1 FLOW-FAULT (see
FLOW-FAULT below) indicator will not function as an out-of-oxygen warning if the pressure in the oxygen cylinder is 500 psi or
less. There may be pressure in the oxygen line but not enough to activate the Pulse-Demand unit, consequently...no FLOW-FAULT
warning. Prior to flying, using the cylinder chart, the pilot should estimate his flight altitude and time to determine the amount
of oxygen that he or she will need. It is better to have more than your estimated need. If a pilot consistently flies above 18,000
feet, the aircraft should have a supplementary gauge, visible during flight by the pilot, to determine the cylinder oxygen pressure.
You should also carry an EOS (Emergency Oxygen System) such as the MH Co-Pilot as a back-up safety feature in case the other
system stops working. It is the absolute responsibility of the pilot to determine that there is an adequate amount of oxygen
pressure in the oxygen cylinder prior to his flight, as well as an emergency back-up in case of a system failure. The oxygen
system must be checked and tested ON THE GROUND before the flight.
O2DELIVERY or NON-DELIVERY
FLOW-FAULT EVENT: The O2 LED Red Light will flash on and off along with a Hi-Lo audio chime for ~ 2 seconds with every
event. NOTE: The FLOW-FAULT is not intended as a low or out-of-oxygen warning. It is only intended to warn the pilot that
there is no oxygen flowing to the EDS O2D1 unit. This typically means that the cylinder valve was not opened, or the supply
line has been pinched closed, or is plugged up, or has come off, or the valve in the O2D1 has failed to open.
FLOW FAULT EVENT
APNEA EVENT: Flash Amber Light four (4) discrete times with audio beeps once every four (4) seconds until unit detects
a valid inhalation event. Time before Apnea event is ~30 ~35 seconds. This typically occurs for the following reasons: (1) The
user has quit breathing for 30 - 45 seconds or the cannula/face mask is improperly worn. (2) The outlet tube from the MH EDS-
O2D1 to the mask or cannula has become disconnected. (3) The outlet tubing has become pinched closed or is plugged off.
The apnea alarm can be used as a “put-your-oxygen-on” alarm once you get to the preset D mode altitude (D5 or
D10). In this case, the alarm will not sound if you already have the cannula or face mask on properly.
APNEA EVENT
USING THE O2D1 WITH A THIRD-PARTY PRESSURE REGULATOR
LOW BATTERY -1: Depending on battery condition, one short flash of the Red Light once every second, no sound. The
unit will continue to operate properly for about six hours @ 77°F (25°C) after the indicator starts to flash. The O2D1 will oper-
ate for ~ 100 hours with a fresh set of DURACELL ULTRA alkaline batteries under normal operation.
LOW BATTERY-1 (First Warning)
LOW BATTERY -2: One short flash of the Red Light once every second, with sound. When this alarm occurs, the
unit may operate for about one hour, then the oxygen flow will then respond with flow-faults or stop and may go into the Bad
Battery Mode. BATTERIES SHOULD BE REPLACED IMMEDIATELY. The O2D1 will operate for ~ 100 hours with a fresh set
of quality alkaline
LOW BATTERY-2 (Second Warning)
BAD BATTERY MODE: Alternating Flashing Red Light on and off at a one (1) second rate with unit functions
locked out, no sound. NOTE: BATTERIES SHOULD BE REPLACED IMMEDIATELY!
BAD BATTERY MODE
If the O2D1 will not be used with a MH Pressure Regulator, the alternate regulator must be able to deliver a pres-
sure of between 15 and 20 psi (static) and ~15 psi dynamic (flowing). If the above listed pressure specifications are
not met, the O2D21`may not operate correctly. Lower pressures will result in an inadequate volume of oxygen. Higher pressures
will result in a too high volume of oxygen. Excessively high pressures will cause the valve to open spontaneously and leak oxygen.
To use the O2D1 with a third-party regulator or built-in oxygen system with a pressure higher than 25 psi, it is mandatory that you
use the MH EDS IN-LINE REGULATOR (EDS-ILR) to ensure correct flow pressure. The EDS-ILR goes between the third-party regulator
or built in system and the O2D1 to reduce the flow pressure to an appropriate level.
6
AUTOMATIC SHUT-DOWN
Abandoned unit auto shut off: If you should forget to turn your EDS off after use, it will go into auto shut-down (draw-
ing very little power) after 3 hours of detecting no use, in an attempt to save the batteries. To re-start, turn switch to off then
back to desired mode. the O2D1 will restart and resume operation.

77
The O2D1 unit emits no sound or start-up oxygen pulse when turned on:
1. Check batteries to make certain they are fresh.
Start-up sound is heard, but no start-up oxygen pulse delivered:
1. Check oxygen cylinder valve is on.
2. Check oxygen supply tube for proper connection.
3. Check oxygen supply tube for obstructions.
4. Check O2D1 outlet tubing for obstructions.
When using the face mask, no oxygen pulse on inhalation:
1. Make sure the face mask is sealed against the skin.
2. Check for obstructions on the O2D1 outlet tubing.
3. Use only face masks provided by Mountain High Equipment & Supply.
NOTE: EDS face masks DO NOT have a plastic dilution bag attached
Oxygen pulses are delivered, but an alarm is heard at the same time:
1. Check the battery to make certain it is fresh.
2. Check for obstructions in the cannula/mask and tubing.
3. Use only masks and cannulas supplied by Mountain High Equipment & Supply.
The O2D1 does not trigger at higher altitudes:
1. Try using the Flared-Tip cannula included with the kit (MH part number 00EDS-1084-01)
TROUBLE-SHOOTING
•
•
•
•
•
WARNING
DO NOT
increase or
decrease length
of cannula or
face mask
supply tubing.
LIMITED WARRANTY
This device is classified as, and is only suitable for use as, a supplementary breathing apparatus (SBA) for aviation use. It is intended to
help supply the needed amount of oxygen for persons during flight altitudes where supplemental oxygen is needed. This device is not
suitable for any type of life support operations. This device is not suitable for SCBA (Self Contained Breathing Apparatus), SCUBA (Self
Contained Underwater Breathing Apparatus) or any medical operations.
Before it is put to use, it is the responsibility of any user who will use this device to become familiar with the operation and safety aspects
of this device. Using the system improperly could cause failure and lead to possible property damage and/or personal injury.
Mountain High Equipment & Supply Company assumes no responsibility for property damage, accidents, injury or death that may result
from the misuse of this device/equipment. This includes any use of this device/equipment outside the scope of common sense, the
Instruction Manual, inserts and other related documentation.
NOTICE OF NON-LIABILITY
Mountain High Equipment & Supply Company warrants your MH EDS-O2D1-2G unit against defects in materials and workmanship for two
(2) years from date of purchase invoice. The warranty is non-transferable. Should any part of the MH EDS-O2D1-2G become defective within
the warranty period, contact our Service Department ([email protected]) to request a RMA (Return Materials Authorization). Return the
EDS Unit and your cylinder pressure regulator with the RMA, including a description of what/why it is not functioning and we will repair or
replace it, at our discretion, free of charge (you pay only shipping to MH).
Return the Unit to:
Mountain High Equipment and Supply Company
Service Department
2244 Airport Way, Suite 100
Redmond OR 97756-8696
This warranty is non-transferable and only valid if Mountain High Equipment & Supply Company determines that the system and its
components have not been damaged due to improper use, been submerged in fluids, dismantled or abused. Mountain High Equipment &
Supply Company reserves the right to determine if repairs are to be done under warranty or at a nominal charge. To activate warranty
coverage, you must complete and return your enclosed owner’s EDS Registration Card.
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MAINTENANCE QUESTIONS
Maintenance Questions for MH EDS 0201-2G PULSE DEMAND™Portable Systems:
Q: I have one of your portable MH-EDS PULSE DEMAND™ units. It seems to be operating just fine, should I send it in for any
type of routine service or testing?
Yes. Even though your pulse-demand unit will generally let you know if there is a problem and has been designed to be
relatively maintenance free except for batteries, it should be sent in on a regular basis for performance inspection and
service. This includes the in-line or screw-on regulator you use with the EDS. Think of it like performing an annual
inspection on your aircraft.
Q: Why has this not been mentioned before and how often does MH recommend this be done?
This service program has been derived from usage and servicing data acquired during the last 20 years the technology
has been in production and fielded. From this, Mountain High has decided on a routine service program that should be
accomplished once every two years, (biennially). This must include the regulator you are currently using with the EDS
unit(s).
Q: What is done to my EDS unit and regulator when I send them in for service?
From time to time we make engineering improvements during our production. These improvements may include
changes to hardware or firmware or both. This is our way of passing on our latest improvements to you. Also routine
service parts such as seals, seats, O-rings and filters are inspected and replaced. Your EDS unit(s) and regulator(s) are
then thoroughly inspected and tested on our AIP test set to ensure they are operating to specified standards. This will
help to ensure your system is operating properly and upgraded to the latest specifications. Any other parts replaced due
to damage or field use would be subject to an additional charge.
Q: How long should I expect this service to take?
Once we receive your unit, in-house turn-around time is generally five to ten working days.
Q: I have sent my EDS unit back once before for a problem of leaking or not responding at certain altitudes, but it came back
with the same problem. Why?
Some problems perceived to be with the EDS units have, in fact, turned out to be with the cylinder pressure regulator.
This has mostly been the case if you are not using the pressure regulator designed for the EDS or are connecting directly
to a built-in system installed in your aircraft. This is why you must include the primary reducing regulator you are using
(ours or not) or tell us that you are connecting the EDS unit(s) directly to your aircraft’s built-in system without our inline
regulator. Many other regulators do not regulate the pressure adequately for the EDS units to operate and deliver the
proper amount of oxygen. Damage can be done to the breathing sensor in the EDS units if the operating
pressure is too high. In addition, we have seen many situations where customers connect the EDS unit to the
connectors and tubing that came with their aircraft. Then plug them into the high-pressure outlets in the aircraft.This
has caused a lot of confusing problems because these connectors generally have flow restriction orifices. In many cases
this has allowed the EDS unit to check out okay at ground level when the pulse response is low, but then complain with
flow fault alarms at higher cruising altitudes. Additionally, this problem can be difficult to reproduce because the EDS
unit operates with pressure altitude and not barometrical corrected altitude.
Q: How and where do I get service on my EDS unit(s)?
Request a RMA (Return Materials Authorization) by e-mailing: [email protected].
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9
WHAT EVERY PILOT SHOULD KNOW ABOUT OXYGEN
What Is Air?
The air surrounding us is a mixture of gases consisting of 78% nitrogen and 21% oxygen. The remaining 1% is made up of argon, carbon
dioxide, and traces of rare gases.
What Is Oxygen?
Under normal conditions, pure oxygen is a colorless, tasteless, odorless, non-combustible gas. It is the most important single element in our
universe.
Why Is Oxygen So Important?
Although it will not burn alone, oxygen supports combustion; in fact, without oxygen there can be no fire. Oxygen, therefore, is not only
necessary for the burning of combustible materials, but it is also absolutely essential to support the process of “vital combustion” which
maintains human life. Although a person can live for weeks without food or for days without water, he or she dies in minutes if deprived of
oxygen. The human body is essentially a converter which consumes fuel and produces heat and energy. It is like a furnace which utilizes the
oxygen in the air to burn coal, thus producing heat and power. The human body must have oxygen to convert fuel (the carbohydrates, fats,
and proteins in our diet) into heat, energy, and life. The conversion of body fuels into life is similar to the process of combustion; fuel and
oxygen are consumed, while heat and energy are generated. This process is known as “metabolism.”
Where And How Do We Normally Obtain Our Oxygen?
At each breath we fill our lungs with air containing 21% oxygen. Millions of tiny air sacs (known as “alveoli”) in our lungs inflate like tiny
balloons. In the minutely thin walls enclosing each sac are microscopic capillaries, through which blood is constantly transporting oxygen
from the lungs to every cell in the body. Because the body has no way to store oxygen, it leads a breath-to-breath existence.
How Much Oxygen Does The Human Body Need?
The rate of metabolism, which determines the need for and consumption of oxygen, depends on the degree of physical activity or mental
stress of the individual. A person walking at a brisk pace will consume about four times as much oxygen as he or she would when sitting
quietly. Under severe exertion or stress, he or she could be consuming eight times as much oxygen as when resting.
What Happens If The Body Does Not Receive Enough Oxygen?
When the body is deprived of an adequate oxygen supply, even for a short period, various organs and processes in the body begin to suffer
impairment from oxygen deficiency. This condition is known as “hypoxia.” Hypoxia affects every cell in the body, but especially the brain and
the body’s nervous system. This makes hypoxia extremely insidious, difficult to recognize, and a serious hazard especially for flight personnel.
What Are The Effects Of Hypoxia?
Hypoxia causes impairment of vision (especially at night), lassitude, drowsiness, fatigue, headache, euphoria (a false sense of exhilaration),
and temporary psychological disturbance. These effects do not necessarily occur in the same sequence nor to the same extent in all individuals,
but are typical in average persons who are affected by hypoxia.
When And Why Must We Use Extra Oxygen?
Supplementary oxygen must be used to enrich the air we breathe to compensate for either a deficiency on the part of the individual or a de-
ficiency in the atmosphere in which we are breathing. A person may have a respiratory or circulatory impairment which reduces the ability of
the body to utilize the 21% oxygen in the air. For such a person, supplementary oxygen must be administered by an oxygen tent or by oxygen
mask to enrich the inhaled air. The total volume of oxygen in each inhalation is then so much greater than normal that it compensates for the
individual’s own physical inability to utilize normal atmospheric oxygen. When we ascend in altitude, a different condition is encountered: a
condition in which the individual may be perfectly normal, but in which there is an oxygen deficiency in the atmosphere and supplementary
oxygen must therefore be used.
Does The Percentage Of Oxygen In The Air Change With Altitude?
No, the ratio of oxygen to nitrogen in the composition of air does not change. The 21% of oxygen in the air remains relatively constant at
altitudes up to one hundred thousand feet.
Why Must We Use Extra Oxygen When We Ascend In Altitude?
The blanket of air which surrounds our planet is several hundred miles thick, compressible, and has weight. The air closest to the earth is
supporting the weight of the air above it and, therefore, is more dense; its molecules are packed closer together. As we ascend in altitude, the
air is less dense. For example, at 10,000 feet, the atmospheric pressure is only two-thirds of that at ground level. Consequently, the air is less
dense, and each lung full of air contains only two thirds as many molecules of oxygen as it did at ground level.At 18,000 feet the atmo-
spheric pressure is only one-half of that at ground level. Although the percentage of oxygen is still the same as at ground level, the number
of molecules of oxygen in each lung full is reduced by one-half. As we ascend, there is a progressive reduction in the amount of oxygen taken
into the lungs with each breath, and a corresponding decrease in the amount of oxygen available for the bloodstream to pick up and trans-
port to every cell in the body. To compensate for this progressive oxygen deficiency, we must add pure oxygen to the air we breathe in order
to maintain enough oxygen molecules to supply the metabolic needs of the body.
At What Altitudes Should Oxygen Be Used?
In general, it can be assumed that the normal, healthy individual is unlikely to need supplementary oxygen at altitudes below 8,000 feet. One
exception is night flying. Because the retina of the eye is affected by even extremely mild hypoxia, deterioration of night vision becomes sig-
nificant above 5,000 feet. Between 8,000 and 12,000 feet, hypoxia may cause the first signs of fatigue, drowsiness, sluggishness, headache,
and slower reaction time. At 15,000 feet, the hypoxic effect becomes increasingly apparent in terms of impaired efficiency, increased
drowsiness, errors in judgment, and difficulty with simple tasks requiring mental alertness or muscular coordination. These symptoms become
more intensified with progressively higher ascent or with prolonged exposure. At 20,000 feet, a pilot may scarcely be able to see, much less
read, the instruments. His or her hearing, perception, judgment, comprehension, and general mental and physical faculties are practically useless.
(continued on next page)
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The pilot may be on the verge of complete collapse.Therefore, the availability and use of supplemental oxygen is recommended on night
flights where altitudes above 5,000 feet are contemplated, and for altitudes above 8,000 feet on daytime flights.
How Can You Tell When You Need Oxygen?
You can’t; therefore, oxygen should be used before it is needed. The most dangerous aspect of hypoxia is the insidious, “sneaky” nature of
its onset. Because the effects of hypoxia are primarily on the brain and nervous system, there is a gradual loss of mental faculties, impair-
ment of judgment, coordination, and skill; but these changes are so slow that they are completely unnoticed by the individual who is being
affected. Actually, a person suffering from mild or moderate hypoxia is apt to feel a sense of exhilaration or security, and may be quite proud
of his or her proficiency and performance although he or she may be on the verge of complete incompetence. Because hypoxia acts upon
the brain and nervous system, its effects are very much like those of alcohol or of other drugs which produce a false sense of well-being.
There is a complete loss of ability for self-criticism or self-analysis. Some people believe that a pilot can detect his or her need for oxygen by
noting an increase in breathing rate, an accelerated heartbeat, and a slight bluish discoloration (cyanosis) of the fingernails. However, by the
time these symptoms develop, the individual is more likely to be mentally incapable of recognizing these signs. The person may even decide
that he or she has always wanted blue fingernails! Even while “spiraling” out of control, the individual may be convinced (if conscious at
all) that he or she is doing this deliberately and enjoying it immensely
Are All Individuals Equally Affected By Hypoxia?
No, they are not. Just as there is a variation among individuals in their ability to tolerate heat, cold, or alcohol, some people can tolerate
without apparent effect a degree of hypoxia which would have noticeable effects on others who are more susceptible to the lack of oxygen.
There is no way to measure and predict hypoxia tolerance because it can be affected by physical condition, fatigue, emotion, tobacco, alco-
hol, drugs, diet and other factors. The individual who has flown at 14,000, 16,000, or 18,000 feet without oxygen and survived has no idea
how close he or she may have been to disaster. The person may believe that all this talk about oxygen need, if true at all, does not apply to
him or her. Such a belief may some day be fatal.
Is It True That Oxygen Is Toxic Or Harmful?
Oxygen therapy is often used for prolonged periods in hospitals and homes not with harmful, but definitely beneficial effects. It is most
generally agreed that a 60% oxygen concentration on the ground, which is equivalent to a 100% oxygen concentration at approximately
12,000 feet, will not cause any harmful effects.
Why Not Use Oxygen Intermittently For Short Periods?
If one is at an altitude where there is an oxygen deficiency, intermittent use of oxygen would only temporarily alleviate the hypoxic effects
during the period in which oxygen is being used. Because of the insidious nature of hypoxia, a person already mildly hypoxic is very unlikely
to even think of using oxygen equipment, either intermittently or otherwise. It is true that occasional use of oxygen for five or ten minutes
(even at altitudes below 8,000 feet) can act as a “refresher” to relieve the effects of mild hypoxia, cigarette smoke, apprehension, or other
factors. Also, the use of oxygen for five or ten minutes before the termination of a flight (even though the entire flight may have been flown
at less than 8,000 feet) can be an excellent tonic to put the pilot in his or her best mental and physical condition for the approach proce-
dures and landing maneuvers.
How Will Oxygen Equipment Improve The Utility Of The Airplane?
With oxygen equipment aboard, the pilot can choose the higher altitudes which give the smoothest flight, the most favorable winds, the
best performance from the Omni and other radio navigation equipment, the highest speed, the longest range, and the best engine perfor-
mance. The pilot can have these advantages safely with oxygen because his or her own performance will not be affected by hypoxia; he or
she will be just as efficient and capable as at lower altitudes or even on the ground. With oxygen equipment in use, pilot and passengers
will arrive at their destination fresh and fit, without the headache, lassitude, and fatigue which often result from prolonged exposure to even
mild hypoxia.
What Types Of Oxygen Equipment Are Available For Private And Executive Aircraft?
There are a variety of types, including portable MH EDS “Pulse-Demand” units which can be carried along when flight at hypoxic altitudes is
anticipated. If flights at such altitudes are frequent, then a “built-in” oxygen system offers some advantages, especially in the larger aircraft.
For either portable or built-in systems there is a choice between “Pulse-Demand” type and “Continuous Flow” type equipment. “Pulse-De-
mand” type equipment automatically delivers oxygen to the user during each inhalation in response to his or her own breathing pattern and
altitude. The continuous flow type system delivers oxygen at a fixed rate to an accumulator bag which is attached to the mask, and from
which the user inhales each breath. The Pulse-Demand is the most efficient.
How Should An Oxygen System Or Equipment Be Selected?
Your MH Sales Engineer can help you at 800-468-8185. He or she can assist the pilot in selecting the system best suited to the specific
airplane and the pilot’s special needs.
WARNING:
Improper use or improper maintenance of aviation oxygen equipment may result in serious injury or death.
Aviation oxygen equipment is intended to be used only for aviation applications and is to be used only
by, or under the supervision of, a pilot or crew member trained and qualified in its use. Aviation oxygen
equipment is to be serviced only in accordance with the applicable component maintenance manuals from
MH Oxygen Systems and only be serviced by technicians trained in the inherent hazards of high pressure
aviation oxygen and knowledgeable of this equipment. Aviation oxygen equipment is to be used only with
oxygen meeting the requirements of MIL-PRF-27210
WHAT EVERY PILOT SHOULD KNOW ABOUT OXYGEN

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AUTO COMPENSATION INFORMATION
EDS O2D1-2G Auto-compensation
Altitude compensated breathing sensor
Because absolute atmospheric pressure lessens as a function of altitude, breathing efforts assert less pressure upon breath-
ing sensors to the point at which they may not properly detect breathing while at higher altitudes. Additionally, as the partial
pressure of CO2 drops below a normalized point with altitude, one’s breathing efforts also diminish. With these two physical
and physiological effects while ascending to higher altitudes, it becomes necessary for the EDS to compensate for this.
The EDS has an active algorithm that constantly and automatically makes breathing sensor sensitivity adjustments based on
detected pressure altitude changes and breathing efforts. This helps ensure that all breaths are detected and responded to
with the proper amount of oxygen without mis-triggering from artifacts. There are no user settings for this function as it is
entirely automatic.
Automatic respire-metric compensation
An adult person of average size (with no compromising pulmonary conditions or illnesses) will have an average respiration
rate between 12 and 18 breaths per minute. Persons between 60 and 75 years of age will generally have a rate between 12
and 28 breaths per minute. The respiration effort at rest generally becomes less as the rate increases. Shallow breathing with
elevated respiration rates are also typical with exposure to lower partial pressures from altitudes and/or anxiety.
With exposure to lower partial pressures from excursions to higher altitudes, breathing efforts will generally lessen as the
partial pressure of CO2 drops along with other atmospheric gases. Respiration is primarily controlled by chemoreceptors that
detect dissolved CO2 in the blood. Higher CO2 levels, from physical work, trigger higher respirations until CO2 is re-normal-
ized. Oxygen levels increase from this as well. Therefore, as the amount of dissolved CO2 reduces in the blood so does the
need to respirate. Unfortunately, this also exacerbates hypoxia as less oxygen is inhaled and admitted into the blood as the
body has no reason to respirate to expel any more CO2.
The EDS has a poly-metric method of dynamically adjusting the amount of oxygen delivered on a breath-by-breath basis as a
function of detected pressure altitude, respiration rate and (in some cases) breathing efforts. Without actually complement-
ing respiration with a small amount of CO2 at higher altitudes to encourage respiration, the EDS will dynamically augment
the amount of oxygen delivered to help ensure that each individual person’s breathing profile is complemented with a
‘best-effort’ schedule of needed oxygen while at higher altitudes. If the EDS is unable to establish meaningful respiremetrics
caused by pneumatic artifacts or mis-fitting cannulas and/or face masks for the current user, it will default to known param-
eters to cover a known mean pulmonary profile.
Compensating for various plenum volumes associated with face masks
A face mask, unavoidably, has a volume of space (plenum) that does not directly contribute to the admission of oxygen. This
plenum can compromise the initial admission of oxygen by allowing the user to re-breathe CO2 rather than oxygen at the
most important point of the inhalation phase, displacing some of the pulse of oxygen. While a small amount of re-inhaled
CO2 can actually be beneficial at higher altitudes as it encourages respiration, missing the full complement of the prescribed
amount of oxygen at altitude is not.
The EDS has four manually operated F-Mode settings, 1 through 4, that provide an additional bolus of oxygen with each
breath to help mitigate this. Each setting provides a progressively larger bolus. This is intended to be used to compensate for
the plenum volume associated with the use of face masks settings 1-2 for small sized masks, 2-3 for medium sized masks
and 3-4 for use with large sized masks. These F-Mode settings can also be used if the user determines that they may need
more oxygen than is automatically prescribed.

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SPECIFICATIONS
Allowable respiration rates: Adaptive: up to 43 bpm. And down to ~ 5 bpm.
Apnea time-out envelope: Adaptive: ~40 sec Pa. 0-12 K ft., ~30 sec. Pa. 13-18 K ft., 20 Sec. at and above Pa. 18 K ft. Apnea
alarm does not respond if in any of the ‘D’ modes and while below that pressure altitude threshold.
Operating inlet pressures: 15 psig. (1 bar) DYNAMIC (owing) through cannula and 1.5 meters (5 ft.) of 4 mm. inlet tubing.
25 psig. (1.72 bar) .
Operating & storage temperatures, altitudes, vibration @ humidity, (assumes nominal operating voltage):
Temp range @ ~10% RH: -40° to +60° C. (Storage for complete unit less battery)
Temp range @ ~25% RH: 0° to +60° C. (Operating with std. valve)
Temp range @ ~100% RH NC: +5° to +60° C. (Operating with std. valve) Unit is not water-proof, keep it dry from
spray & rain.
Altitudes @ up to ~100% RH: -100 to +30 K ft. Pressure Altitude range @ +5° to +60° C. (Operating with std. valve)
Vibration: Random vibration 5 to 500 Hz, 15 minutes per axis @ 2.5 g. (rms) sin wave.
Physical characteristics (O2D1 unit only):
Width @ widest point: 3.10” (79 mm);
Height, including connectors: 5.23” (130 mm.);
Height, enclosure only: 4.62” (117 mm);
Thickness, front to rear: 0.95” (24.13 mm)
Weight: 7.5 Oz. (0.213 g.) with batteries
Operating Voltage & Current @ 25° C. @ ~25% RH.
(Measured in the ‘N’ mode setting @ 15 RESP/ typical.):
Battery types: 2 each 1.5 volt alkaline type ‘AA’
DURACELL ULTRA alkaline batteries or equivalent.
Battery Life: 100 Hrs. @ ~25° C. @ ~25% R.H. Measured from
mean, assuming fresh DURACELL ULTRA alkaline batteries operating under normal operating conditions.
NOTE: Make sure alkaline batteries are used and removed during long-term storage.
Nominal battery voltage: ~2.875 VDC ± 40 mv.@ 2.25 ma. Idle. 100 ma. Peak (~50 ms. max), 3.25 ma. Average.
Min. start-up voltage: ~2.5 VDC ± 40 mv.
Low-battery cut-out: < 2.0 VDC ± 40 mv. (Red light on steady unit in non-responsive state ‘dead’)
Very low battery signal: ~2.25 VDC ± 40 mv. (Red light winking 2/sec.) ~5 Hrs. of service left.
Low battery signal: ~2.4 VDC ± 40 mv. (Red light winking 1/sec.) ~12 Hrs. of service left.
Notes:
The low battery cut-out feature provides a known state of action if the batteries are depleted to the point of inadequate power to operate
the unit to any of the declared specications. In addition, this feature was found to be prudent because, while many of the specications
may stay intact, false triggering of the valve may confuse the operator of a problem other than low batteries. The minimum ‘start-up’
voltage is where the unit will initiate the built-in test and commence operations. However, it should be noted that during this operation if
the batteries are then measured to be too low, the lock-up feature may then shortly ensue. This should help the operator in determining
if the unit is bad or if the batteries are too low. A unit that has low batteries that cause ‘lock-up’ will most likely initially start-up if left off
for some time. Alkaline type batteries have so-called self-rejuvenating properties that may cause the user to forestall battery replacement.
Obviously, dead batteries will yield no action.
The O2D1 Specifications, performance standards and limits are derived from actual units tested,
characterized or calculated. Specifications are subject to change without notice.
800-468-8185 • 541-923-4100 • Fax: [phone] • www.MHoxygen.com • 2244 SE Airport Way, Suite 100 Redmond OR 97756-7537
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Height
Depth
Width