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EXAMINATION PROCEDURE FOR APPLICANTS WITH A
POTENTIAL HEARING DISORDER
The examination may be conducted in the following way:
a) Any extraneous material in the auditory canals (cerumen, purulent material, debris), which may
impede the passage of sound waves or prevent the tympanic membrane or middle ear from being seen,
is removed.
b) Whispered and conversational voice tests are carried out. A 512 Hz fork is used to do a Weber and a
Rinne Test.
c) An audiogram is taken, showing both air and bone conduction graphs for each ear and indicating what
fraction (percentage) of the hearing range has been rendered inaudible.
d) The examinee is asked to state the effect of noisy surroundings, his ability to understand telephone
conversation, and in addition, his reaction (pain, distress) to loud noises. His statements are recorded.
e) The tympanic membrane is carefully examined and its mobility observed with a Siegle-type
otoscope10 (pneumatic).
f) In cases of conductive deafness, an attempt is made to introduce air into the middle ear (Valsalva
manoeuvre, Politzer method11, Eustachian catheter). An observation (or history) of appreciable
improvement in hearing (even though transient) following the introduction of air is recorded.
With the exception of the audiogram, all of the above information can be obtained in a few minutes, and
designated medical examiners should possess the apparatus used in obtaining it. The use of an impedance
meter for tympanometry and reflex measurements can be of great value.
Speech-in-noise test
If an applicant fails to meet the pure-tone audiometry hearing requirement, he may be declared fit if he has
"normal hearing performance against a background noise that reproduces or simulates the masking properties
of flight deck noise upon speech and beacon signals" (Annex 1, 6.3.4.1.1)). In the assessment of applicants for
air traffic control duties, 6.5.4.1.1 indicates that the applicant may be declared fit provided that he has "normal
hearing performance against a background noise that reproduces or simulates that experienced in a typical air
traffic control working environment."
10 Siegle otoscope: an otoscope with a bulb attachment by which the air pressure in the external auditory canal can
varied. After Emil Siegle, German otologist (1833-1900).
11 Politzer method: inflation of the Eustachian tube and tympanon by forcing air into the nasal cavity at the moment
when the patient swallows. After Adam Politzer, German otologist (1835-1920).
ICAO Preliminary Unedited Version — October 2008 III-12-19
The significance of speech-in-noise tests rests on the finding that aviation personnel with hearing loss,
generally caused by exposure to aircraft noise during many years of service, may be able to understand
communications under flight deck noise as well as those with normal hearing. This apparent improvement of
hearing under noise is called recruitment. Flight safety under these conditions is not impaired as long as it is
made certain in each case that intelligibility of speech and perception of signals under background noise, as
well as hearing on the ground for briefing and check-list procedures is satisfactory (Annex 1, 6.3.4.1.1, Note
1). Such a test can be performed under different conditions for reproducing or simulating flight deck noise:
white noise, tape recordings in flight, flight simulators or flight tests may be used. However, flight-deck noise
levels and spectra differ between aircraft types (Table 12-3). A high noise level is not considered an essential
factor as tests may also be carried out at lower noise levels (70-110 dB have been used, taking into account
conditions prevailing in some aircraft, including take-off and landing).
The speech-in-noise test is further a screening procedure aimed at ensuring that applicants can reliably
perceive radio communications and acoustic signals (beacons, warning signals); they must also hear
aerodynamic flow (speed, approaching stall), engine performance and sounds associated with aircraft systems
and instruments. Voice communications between crew members in the cockpit including instructions and
routine check-list operations must be clearly understood, also during approach, landing and emergency
operations.
The distances between pilots in the average airline flight deck varies from 0.6 to 1.2 m (2 to 4 ft), while the
pilot-to-flight engineer distance is 0.6 to 1.8 m (2 to 6 ft).
Instrument landing system (ILS) modulation frequencies are: inner marker 3 000 Hz, middle marker 1 300 Hz,
outer marker 400 Hz (Annex 10, Vol. I, 3.1.6.4). NDB (non-directional beacon) modulating tone for
identification is 1 020 Hz ± 50 Hz or 400 Hz ± 25 Hz.
The characteristics and intensity of flight-deck noise largely depend on the various types of aircraft and their
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Manual of Civil Aviation Medicine 2(83)
