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difference in pressure between the middle ear and
aircraft cabin can build up to a level that will hold the
eustachian tube closed, making equalization difficult
if not impossible. The problem is commonly referred
to as an “ear block.”
3. An ear block produces severe ear pain and
loss of hearing that can last from several hours to
several days. Rupture of the ear drum can occur in
flight or after landing. Fluid can accumulate in the
middle ear and become infected.
4. An ear block is prevented by not flying with
an upper respiratory infection or nasal allergic
condition. Adequate protection is usually not
provided by decongestant sprays or drops to reduce
congestion around the eustachian tubes. Oral
decongestants have side effects that can significantly
impair pilot performance.
5. If an ear block does not clear shortly after
landing, a physician should be consulted.
c. Sinus Block.
1. During ascent and descent, air pressure in the
sinuses equalizes with the aircraft cabin pressure
through small openings that connect the sinuses to the
nasal passages. Either an upper respiratory infection,
such as a cold or sinusitis, or a nasal allergic condition
can produce enough congestion around an opening to
slow equalization, and as the difference in pressure
between the sinus and cabin mounts, eventually plug
the opening. This “sinus block” occurs most
frequently during descent.
2. A sinus block can occur in the frontal sinuses,
located above each eyebrow, or in the maxillary
sinuses, located in each upper cheek. It will usually
produce excruciating pain over the sinus area. A
maxillary sinus block can also make the upper teeth
ache. Bloody mucus may discharge from the nasal
passages.
3. A sinus block is prevented by not flying with
an upper respiratory infection or nasal allergic
condition. Adequate protection is usually not
provided by decongestant sprays or drops to reduce
congestion around the sinus openings. Oral decongestants
have side effects that can impair pilot
performance.
4. If a sinus block does not clear shortly after
landing, a physician should be consulted.
d. Decompression Sickness After Scuba Diving.
1. A pilot or passenger who intends to fly after
scuba diving should allow the body sufficient time to
rid itself of excess nitrogen absorbed during diving.
If not, decompression sickness due to evolved gas can
occur during exposure to low altitude and create a
serious inflight emergency.
2. The recommended waiting time before going
to flight altitudes of up to 8,000 feet is at least
12 hours after diving which has not required
controlled ascent (nondecompression stop diving),
and at least 24 hours after diving which has required
controlled ascent (decompression stop diving). The
waiting time before going to flight altitudes above
8,000 feet should be at least 24 hours after any
SCUBA dive. These recommended altitudes are
actual flight altitudes above mean sea level (AMSL)
and not pressurized cabin altitudes. This takes into
consideration the risk of decompression of the
aircraft during flight.
8−1−3. Hyperventilation in Flight
a. Hyperventilation, or an abnormal increase in
the volume of air breathed in and out of the lungs, can
occur subconsciously when a stressful situation is
encountered in flight. As hyperventilation “blows
off” excessive carbon dioxide from the body, a pilot
can experience symptoms of lightheadedness,
suffocation, drowsiness, tingling in the extremities,
and coolness and react to them with even greater
hyperventilation. Incapacitation can eventually result
from incoordination, disorientation, and painful
muscle spasms. Finally, unconsciousness can occur.
b. The symptoms of hyperventilation subside
within a few minutes after the rate and depth of
breathing are consciously brought back under
control. The buildup of carbon dioxide in the body
can be hastened by controlled breathing in and out of
a paper bag held over the nose and mouth.
2/19/04 AIM
Fitness for Flight 8−1−5
c. Early symptoms of hyperventilation and
hypoxia are similar. Moreover, hyperventilation and
hypoxia can occur at the same time. Therefore, if a
pilot is using an oxygen system when symptoms are
experienced, the oxygen regulator should immediately
be set to deliver 100 percent oxygen, and then the
system checked to assure that it has been functioning
effectively before giving attention to rate and depth of
breathing.
8−1−4. Carbon Monoxide Poisoning in
　
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