6-7: High Altitude and Oxygen Use
A. Preparation and planning critical
- Skydives from altitudes higher than 15,000 feet above mean sea level (MSL) present the participants with a new range of important considerations.
- The reduced oxygen, lower atmospheric pressure and temperature, and the higher winds and airspeed above 15,000 feet MSL make skydiving more hazardous in this region than at lower altitudes.
- Hypoxia, or oxygen deficiency, is the most immediate concern at higher altitudes.
- Hypoxia can result in impaired judgment and even unconsciousness and death.
- Hypoxia can be prevented by the use of supplemental oxygen and procedures not required for skydives from lower altitudes.
- With proper training, adequate equipment, and well-planned procedures, high altitude skydives can be conducted within acceptable safety limits; without such precautions, they may result in disaster.
- These recommendations are presented to familiarize skydivers with:
- altitude classifications
- experience recommendations
- training recommendations
- equipment recommendations
- procedural recommendations
- General information is provided on the accompanying Planning Chart.
C. Altitude classifications
- Low altitude: below 15,000 feet MSL
- Intermediate altitude: from 15,000 feet up to 20,000 feet MSL
- High altitude: from 20,000 feet up to 40,000 feet MSL
- Extreme altitude: above 40,000 feet MSL
D. Experience recommended
- For intermediate-altitude jumps (15,000-20,000 feet MSL), participants should hold at least a USPA B license and have made 100 jumps.
- For high-altitude jumps (20,000-40,000 feet MSL), participants should:
- hold a USPA C license
- have made at least one jump from 15,000 feet MSL or below using the same functioning bailout oxygen system
- For extreme-altitude jumps (40,000 feet MSL and higher), participants should:
- hold a USPA D license
- have made at least two jumps from below 35,000 feet MSL using the same functioning bailout oxygen and pressure systems
E. Training recommendations
- It is a benefit for participants on intermediate-altitude skydives to have completed physiological flight training (PFT) within the preceding 12 months.
- It is essential for all participants on high- and extreme-altitude skydives to have completed PFT within the preceding 12 months.
- PFT availability:
- The FAA’s Civil Aerospace Medical Institute offers a one-day aviation physiology course at the Mike Monroney Aeronautical Center site in Oklahoma City, OK with a hypobaric chamber that creates high-altitude and rapid-decompression scenarios.
- Additional locations run by private companies are available in various locations across the U.S.
- To attend training, applicants for PFT must hold at least a current FAA class 3 medical certificate.
- The PFT course:
- familiarizes the skydiver with the problems encountered in the high-altitude environment
- introduces basic high-altitude oxygen and pressure equipment and its use
- provides the opportunity to discover individual reactions to hypoxia and other altitude diseases through simulated high-altitude flights in a decompression chamber
- First, view the CAMI web site at:
- Directions and enrollment instructions can be found at:
F. Recommended equipment
- A sensitive altimeter and adequate protective clothing are recommended for skydives from above 15,000 feet MSL in addition to the oxygen and body pressurization equipment listed below.
- In the event of a malfunction in the primary systems and components, backup oxygen systems and components should be available on board the aircraft.
- Intermediate-altitude jumps: A separate oxygen mask should be provided for each skydiver and aircrew member, although a common central oxygen bottle and regulator system may be used.
- High-altitude jumps:
- All skydivers must be equipped with an appropriate on-board oxygen source and compatible bailout oxygen system, preferably with a backup bottle (see Planning Chart following this section).
- An automatic activation device (AAD) is recommended.
- Extreme-altitude jumps:
- All skydivers must be equipped with compatible on-board and bailout oxygen and body pressurization systems appropriate to the goal altitude (see Planning Chart following this section).
- An AAD is recommended.
G. Recommended preparations
- All jumps must be coordinated in advance with the appropriate local, state, and federal aviation authorities.
- All jumps should be coordinated in advance with USPA for safety and for establishing new national and international skydiving records under the FAI Sporting Code.
- Oxygen monitor:
- For group jumps from above 15,000 feet MSL, it is helpful to appoint an oxygen monitor whose duties are to:
- inspect, operate, and monitor the oxygen systems during their use
- watch for symptoms of hypoxia and other altitude diseases in all jumpers
- initiate appropriate remedial measures in the event of oxygen equipment malfunction or jumper illness
- see that oxygen equipment is properly stowed before exit
- There should be one oxygen monitor for each six persons or each oxygen bottle, whichever is fewer.
- Communications in the aircraft are extremely limited by the wearing of oxygen masks.
- The spotter and oxygen monitor should establish with the jumpers and aircrew a standard set of hand signals for the commands, inquiries, and responses required during flight.
- A small blackboard or similar device may be helpful for communicating lengthier messages.
- Warning: Oxygen explosively accelerates burning.
- To prevent damage to aircraft and equipment and injury to persons from oxygen-fed flash fires, the aircraft should be electrically grounded during all ground practice.
- No smoking should be permitted in the vicinity of the aircraft, either on the ground or aloft, while oxygen equipment is on board.
- Ground practice
- Ground practice is essential because of—
- restrictions on communication
- the additional pre-exit activities required
- restricted vision (by the mask)
- restricted movement
- results from bulkier clothing
- is often further irritated by long periods of sitting and low cabin temperatures during the climb to jump altitude
- Signals and exit procedures should be practiced on the ground in the actual jump aircraft until everyone can perform the procedures—
- by hand-signal command
- smoothly and without discussion
- Practice will prevent confusion aloft that may result from inadequate rehearsal.
- Equipment checks:
- Equipment should be checked prior to loading the aircraft and especially before exit.
- In addition, the oxygen monitor should perform the “P.D. McCRIPE” oxygen equipment inspection:
Connections at mask
Connections at disconnect
Portable unit (walk-around bottle)
Emergency cylinders (bailout bottles)
H. Oxygen use procedures
Oxygen use procedures will vary with the equipment used, but the following are basic.
Extreme altitude: Standard procedures are not established, but must be developed for the specific mission and equipment.
- Intermediate altitude:
- All participants should put on masks and begin breathing oxygen at 8,000 feet MSL.
- Breathing should be continuous throughout the remainder of the climb and jump run.
- This procedure should be conducted under the supervision of the oxygen monitor.
- This procedure is important (even if it doesn’t seem necessary), especially if more than one jump per day is planned.
- Two minutes from exit—
- The spotter signals “get ready.”
- At this time, all jumpers move into the ready position and prepare to remove their oxygen masks.
- prior to exit—
- Jumpers should stay on oxygen for as long as possible, removing their masks at the “climbout” or “exit” signal.
- The spotter need do nothing further than signal or lead the exit.
- In the event of an aborted jump run, the oxygen masks should be redistributed and donned, a wide orbit made, and the process repeated, with all skydivers again breathing oxygen until within 30 seconds of exit.
- High altitude:
- All skydivers should pre-breathe 100% oxygen under the supervision of the oxygen monitor for 30 minutes prior to takeoff when goal altitude is above 25,000 feet MSL.
- When goal altitude is lower than 25,000 feet MSL, all skydivers should begin breathing from their on-board oxygen source at 8,000 feet MSL, under the supervision of the oxygen monitor.
- Five minutes before exit, the spotter signals “get ready.”
- Two minutes from exit—
- The spotter signals two fingers and gives the command to activate bailout bottles, activates his own and, when he feels its pressure, disconnects from the aircraft oxygen system.
- To prevent goggles from fogging, jumpers should leave their goggles raised until bailout bottle activation is completed.
- Once on the bailout bottle, the spotter goes back to spotting.
- The oxygen monitor gives the spotter the “thumbs up” signal when all other jumpers have functioning bailout bottles and are disconnected from the aircraft oxygen.
- The spotter then need only signal or lead the exit.
- In the event of malfunction of the skydiver’s first bailout bottle, there is sufficient time (two minutes) to switch to the backup bottle.
- In the event that no backup bottle is carried, the skydiver would be forced to remain connected to the aircraft oxygen system.
- After the other jumpers exit, the jumper should descend to 20,000 feet MSL or lower, then jump or land with the aircraft.
I. Spotting procedures
- Direction of the wind at altitude and on the surface may not coincide.
- Winds aloft may also be stronger than surface winds (the jet stream is found at high altitude).
- Adjust the exit point for freefall drift to allow for winds aloft.
- Exit point and opening point will not coincide.
- The higher ground speeds attained by an aircraft indicating the same airspeed as usual at lower altitude radically increases the distance of forward throw that will be encountered on exit.
- To calculate the exit point, consult FAA Flight Service for the winds aloft up to the planned exit altitude.
- Using an average freefall rate of 10,000 feet per minute, compute the time required to freefall through each different layer of wind direction and speed reported.
- Insert the time and wind speed figure into the following equation and solve for wind drift through each layer:
Drift = Wind Velocity x Time of Exposure
(1) The time component of wind speed and time of exposure must both be expressed in or converted to the same units, (i.e., feet per second and seconds, miles per hour and hours).
(2) The drift distance will then be expressed in the same unit as the distance unit of the wind speed figure.
- Use a sheet of acetate, a grease pencil, and a map or aerial photo of the DZ and surrounding area to plot the exit point.
- On the acetate, mark a north-south reference line.
- Then beginning with the topmost wind layer and proceeding to the lowest layer:
- In the same scale as the map or photo, plot the computed wind drift for each by a line.
- Join the beginning of the line representing the drift anticipated in the next lower layer to the end of the line from the one above.
- The resulting zigzag line represents the total wind drift expected during freefall, without tracking.
- In the opposite direction of the exit altitude wind drift (or in the direction of the jump run if it is not to coincide with the wind direction) add 2,000 feet to compensate for forward throw from the aircraft.
- Throw wind-drift indicators at the planned opening altitude to determine the opening point, then, orient the acetate over the photo or map.
- Place the end of the freefall wind drift line on the opening point indicated by the wind drift indicators.
- The other end of the wind drift line now indicates the exit point.
- Jump run should be oriented directly into the wind at exit altitude to prevent lateral drift if spotting is to be primarily visual.
- Navigational aids may be used as the primary spotting reference, but the spot should always be confirmed visually prior to exit.
J. Hazards of openings at higher altitudes
- As terminal velocity increases, so does the rate of change in speed from freefall to open canopy.
- At normal opening altitude, terminal velocity is about 160 feet per second (fps) and the rate of descent under open canopy is about 15 fps; thus, the change in velocity at opening is about 145 fps.
- By comparison, the figures for an opening at 40,000 feet MSL are 336 minus 40, or a 296 fps change in velocity in the same period of time.
- At 60,000 feet MSL the change in velocity is even more striking: 543 minus 64, or 479 fps.
- Because of the higher terminal velocity at the higher altitudes—
- It is clear that an inadvertent opening can cause serious injury as result of the greater opening shock experienced.
- In addition, the equipment may not be able to withstand the load without damage.
- Even if a skydiver were not injured and the equipment not damaged, he or she would still face an extended period of exposure to the extreme cold at altitude.
- Another hazard of a canopy opening at higher altitude is hypoxia.
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