Altitude Chamber Flight Profile Type B (1973-1989): After being
medically screened for any predisposing factors that could be
aggravated by altitude, acceptable students were seated in the
training chamber and taken to 6,000 ft (1,829m) at 3,000 ft (914m)
per minute. The chamber was returned to 2,000 ft (610m) at a rate
of 3,000 ft (914m) per minute. Students suspected of having
trapped gas problems or exhibiting unsuitable psychological mani-
festations were removed from the flight and these reactions are
included in Table 1. The chamber was next evacuated to 8,000 ft
(2,438m) at a rate of 3,000 ft (914m) per minute. Quick don
oxygen masks were in the hanging position next to each student.
Decompression was initiated to 18,000 ft (5,486m) during a 5 sec-
ond time period. After students donned their masks, the chamber
continued to 25,000 ft (7,620m) for the hypoxia demonstration.
Students experiencing hypoxia at 25,000 ft (7,620m) were re-
stricted to a maximum time of 5 minutes without supplemental
oxygen. After the hypoxia demonstration, the chamber was returned
to ground level at a rate of 3,000 ft (914m) per minute. Pressure
breathing and voice communication against positive pressure were
practiced by each student on the descent. Average flight time was
34 minutes. Denitrogenation was not a prerequisite for these
flights. Figure 2 illustrates the Altitude Chamber Training Pro-
file Type B.

FIGURE 2. FAA ALTITUDE CHAMBER PROFILE TYPE B.
(1973 - 1989)

30

20

10

ALTITUDE (Feet)

0) 10 20 30 40

TIME (Minutes)



REFERENCES

1. Valdez, Charles D. Ten-Year Survey of Altitude Chamber Reactions Using The FAA
Training Chamber Flight Profile. FAA Office of Aviation Medicine Report FAA

AN-77-4, 1977.

2. Federal Aviation Regulation Part 67 Medical Standards and Certification,
September, 1974.

3. Air Force Regulation 50-27, Air Force Aerospace Physiological Training Program,
June, 1987. se

é

Us S. GOVERNMENT PRINTING OFFICE: 1990-~$61-020/20438



Decompression sickness reactions were suspected on ten flights with inside observers
accounting for most of the reactions. Table 2 illustrates the reactions.

TABLE 2 - FAA DECOMPRESSION SICKNESS REACTIONS
SusPecTED DECOMPRESSION SICKNESS

STUDENTS
SYMPTOM ALTITUDE RESULTS
Elbow Pain 25,000 ft (7,620m) Relieved at 24,000 ft (7,315m)
Ankle Pain 23,000 ft (7,010m) Relieved at G.L.
Shoulder Pain 18,000 ft (5,486m) Relieved at 10,000 ft (3,048m)

INSIDE OBSERVERS

SYMPTOM = st—té«CAWLETITUDE = «RESULTS.

Joint Pain 29,000 ft (8,991m) Relieved at 27,000 ft (8,229m)
Wrist Pain 28,000 ft (8,534m) > Relieved at 22,000 ft (6,705m)
Knee 25,000 ft (7,620m) Relieved on descent
Parasthesia (foot) 23,000 ft (7,010m) Relieved at 13,000 ft (3,962m)
Shoulder 25,000 ft (7,620m) Grounded

Neck, Arm and 25,000 ft (7,620m) Grounded

Shoulder Pain :

(several episodes)

One inside observer, with over 30 years of participation in altitude chamber exposure,
experienced two reported and several undocumented episodes of neck, shoulder, and
arm pain over a two-year period. Dull chronic pain over these areas of the body intens-
ified with increased frequency of exposure. Parasthesia and elevated levels of pain
would persist for 2 or 3 days following each exposure to altitude. Orthopedic and
neurologic evaluation of this individual resulted in these findings:

(1) 75% flexion, extension and rotation of his neck with
pain on forced neck rotation.

(2) 1 + hypoactive left biceps reflex.



RESULTS AND DISCUSSION

During the 23-year reporting period, 12,759 students were exposed to these training
Profiles. A total of 1,503 training flights were conducted. Recorded altitude chamber
reactions were: aerotitis media (N=882), aerosinusitis (N=200), aerodontalgia (N=20),
hyperventilation (N= 15), abdominal distress (N= 19), claustrophobia (N=2), suspected
decompression sickness (N= 10), apprehension (N=9), tingling (N=3), and uncon-
sciousness (N=1) for a total of 1,161 reactions. Table 1 enumerates the altitude
chamber reactions.

TABLE 1 - FAA ALTITUDE CHAMBER REACTIONS

PROFILE TYPE A PROFILE TYPE B

SYMPTOM (1965-1971) * (1973-1989) *
479 Flights 1,024 Flights

3.034 Students _9,725 Students _ TOTAL

Aerotitis Media 248 634 882
Aerosinusitis 81 119 200
Aerodontalgia 6 14 20
Hyperventilation 3 °12 15
Abdominal Distress 5 14 19
Claustrophobia 2 0 2
Decompression Sickness 2 8 10
Apprehension is] 9 9
Tingling 0 3 3
Unconsciousness 0 1 1

1,161

*Data from the years 1972 and 1985 were not available.

The three reported cases of tingling occurred following pressure breathing and may
have been related to hyperventilation. During a hypoxia demonstration at 22,500 ft
(6,858m), one student lost consciousness one minute and 54 seconds into the demon-
stration. He remained unconscious during the emergency descent until the chamber
reached an altitude of 8,000 ft (2,438m).



1. Will age contribute to the susceptibility to decompression
sickness?

2. On a weekly basis and over a period of many years, will rapid
decompressions and altitude exposures to 25,000 ft (7,620m)
\ and above predispose an individual to orthopedic or neurological
t problems during the latter years of life?

ie 3. Over a period of many years, will frequency and duration of
altitude exposure, as defined in this report, adversely effect
respiration and circulation, the digestive system, hearing and
other body systems?

4. Does altitude exposure offer any beneficial effects on the body
systems?

if future research should support the premise that age and long-term exposure to
altitude have a deleterious effect on the body, then different safeguards may be needed
for senior inside observers. Some safeguards to be considered may include: :

1. An age limit or years of exposure limit for inside observers.

2. A modified weekly maximum exposure level for inside observers
that considers long-term exposure and upper-age range.

3. Continuation and expansion of an annual routine physical
examination to include a preventive program, which may incor-
porate a cardiac stress test, periodic X-rays of the chest
and major joints, a pulmonary function test, and serum
chemistry.





(3) Plain X-ray evidence of marked narrowing of the disc
space at C6-C7 and narrowing of the C7 root foramen.

(4) Plain X-ray evidence of narrowing of the L5-S1 disc
space.

(5) Magnetic Resonance Imaging scan showed no nerve root
compression in the cervical spine. Slight bulging of
the L5-S1 disc was not considered severe enough to
warrant surgical treatment.

(6) Neurological examination was normai except for inter-
mittently depressed left biceps tendon reflex as above.

(7) Nerve conduction velocities and electromyogram were
normal, showing no significant neuromuscular damage.

This inside observer has been restricted from any future altitude chamber flight on the
basis of cervical radiculopathy with clear-cut symptomatology aggravated by altitude.

Another inside observer with over 30 years of participation in altitude chamber flights
experienced shoulder pain at 25,000 ft (7,620m) during a research chamber flight. The
chamber profile for this flight was similar to the training flight, except for a 3 minute

stop at 15,000 ft (4,572m) on the way to 25,000 ft (7,620m) and a 3 minute stop at
15,000 ft. (4,572m) on the way to ground level. Denitrogenation was not included in the
protocol and total flight time was 46 minutes including 4 minutes at 25,000 ft (7,620m).
Pain persisted after the flight and skin mottling was evident the following morning. This
inside observer continued to have soreness and pain for the next two weeks and was
referred to the aviation medicine experts for evaluation. Bone necrosis was not found,
but he was diagnosed as having tendonitis and bursitis with the impression that years of
repeated episodes of untreated limb bends may have contributed to the development of
a painful shoulder. He also was restricted from any future altitude chamber flights.

Examination of the data suggests that although some students did experience mild and
expected altitude reactions, these training profiles appear to provide a safe learning
environment while meeting the training needs of the aviation public. Considering the
nominal medica! requirement, unknown physical condition of students, different levels
of student experience, and the minor reactions cited, continuation of the profiles is
indicated.

CONCLUSIONS

Although there were some mild and expected reactions from chamber trainees, the
training profiles appear to provide a safe learning environment without compromising the
student's health and safety. However, data from the older inside observers used in
these chamber flights tend to raise several questions. These include:



FAA second class medical certificate, which is valid for one year. Maximum exposures
are in accordance with U.S. Air Force Regulation (AFR) 50-27 (3) which permits two
rapid decompressions in a 7 day period with at least 24 hours between exposures to
rapid decompression. Routinely, all inside observers received the maximum exposure
permitted during this 23 year period. On every training flight, inside observers are
subjected to an altitude chamber flight and rapid decompression.

METHODS

During the 23 years cited in this report, the following profiles were conducted:

Altitude Chamber Flight Profile Type A (1965-1971): After a routine medical inquiry

of each student's physical condition, the students take assigned seats in the altitude
chamber. An evacuation to 7,000 ft (2,133m) at a rate of 3,000 ft (914m) per minute
begins. The chamber operator levels the chamber on reaching 7,000 ft (2,133m) and
lowers the chamber to 2,000 ft (610m) at a rate of 2,000 ft (610m) per minute. On
reaching ground level, any student suspected of being a candidate for sinusitis or
aerotitis media is removed from the chamber. The chamber run is then continued, at a
rate of 3,000 ft (914m) per minute, to 29,000 ft (8,839m), where the students experience
symptoms of hypoxia. Exposure to 29,000 ft (8,839m) averages about 8 minutes. After
the demonstration, the chamber returns to 8,000 ft (2,438m) at a rate of 2,000 ft (610m)
per minute. The students next experience a decompression from 8,000 ft (2,438m) to
29,000 ft (8,839m) in 20-24 seconds. On arriving at 29,000 ft (8,839m), the chamber
descends to ground level at a rate of 2,000 ft (610m) per minute. If pressure breathing
equipment is used during the flight, pressure breathing and communication techniques
are demonstrated. The total time of the chamber flight averages about 45 minutes.
Figure 1 illustrates the Type A Profile. 7

FIGURE 1. FAA ALTITUDE CHAMBER PROFILE TYPE A

40
30

20

ALTITUDE (Feet)

10

TIME (Minutes)


THE FAA ALTITUDE CHAMBER TRAINING FLIGHT PROFILES:
A SURVEY OF ALTITUDE REACTIONS - 1965-1989

INTRODUCTION

Since 1962, physiological training has been available to the aviation populace at the
Federal Aviation Administration’s (FAA) Civil Aeromedical Institute (CAMI) in Oklahoma
City, Oklahoma. /The curriculum consists of five to six hours of classroom instruction in
aviation physiology subjects and an altitude chamber flight with rapid decompressiori/
Students may consist of flight attendants, engineers, student pilots, flight examiners, and
airline flight crews.

Participants in the altitude chamber must meet the following requirements:
1. Minimum age of 18 years (no maximum age limit).
2. Students may not wear beards.

3. Students must be free from colds or allergies and have no
afflictions that could be aggravated by atmospheric
pressure changes.

4. Students must hold a valid FAA Medical Certificate.
5. An Assumption of Risk and Treatment statement must be signed.

Three classes of medical certificates are issued by the FAA based on medical stand-
ards established by law and contained in the Federal Aviation Regulations (FAR) Part 67
(14 CFR 67) (2). First class certificates are required for airline transport pilots,

second class certificates for commercial pilots, and third class certificates for private
and student pilots.

First class medical certificates require an electrocardiogram (EKG) at age 35 and
annually after age 40. EKGs are not standard requirements for second and third class
certificates. Except when additional medical information is required, serum chemistry
tests are not required for certification in any of the three classes.

ALTITUDE CHAMBER INSTRUCTORS

Four instructors are required to operate an FAA altitude chamber flight: a chamber
operator, a flight recorder, and two inside observers; also, a flight surgeon must be on
telephone standby. The inside observers who participated in these series of training
flights are all ex-U.S. Air Force chamber technicians with many years of altitude chamber
experiences. Three of the four instructors have been participating for over 30 years in
exposures to reduced atmospheric pressure. All inside observers possess a current

1



Technical Report Documentation Page

1, Report No. 2. Government Accession No, 3. Recipient's Catalog No.

-DOT/FAA/AM-90/12

‘4. Title and Subtitle

5. Revert Dare September 1990
The FAA Altitude Chamber Training Flight

Profile: A Survey Of Altitude Reactions 6. Performing Organization Code
1965 - 1989

lB. Performing Organization Report No.

7. Author! s)

CHARLES D. VALDEZ, M.P.H.

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)
FAA Civil Aeromedical Institute
P.O. Box 25082 11. Contract or Grant No.

Oklahoma City, Oklahoma 73125

13. Type of Report and Period Covered

12. Sponsoring Agency Name and Address

Office of Aviation Medicine
Federal Aviation Administration

800 Independence Avenue, S.W. 14. Sponsoring Agency Code
Washington, D.C. 20591 FAA

15. Supplementary Notes

16. Abstract

Reactions from 1,161 trainees out of 12,759 trainees subjected to the
FAA altitude chamber training flights from 1965-1989 are annotated in
this survey. Although there were some mild and expected reactions,
these training profiles appear to provide ‘a safe learning environment
without compromising the student's health and safety. Inside chamber
instructors did not fare as well, perhaps due to age and cumulative
number of exposures, and recommendations are suggested for improved
safeguards.

17, Key Words > 18. Distribution Statement
valtitude Chamber; Deconess.or Document is available to
Aerotitis Media; the public through the
VAerosinusitis; Evolved Gases; National Technical
Denitrogenation; Information Service,
Altitude Reactions Springfield, Virginia 22151
T9. Security Classif. (of this report) 20, Security Classif. (of this page) 2 No. of Pages | 22. Price
Unclassified Unclassified 12

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