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communication under a headset (insert protectors used with communication earphones or earphones
incorporated into ear muffs). Problems in speech communication depend on the type and the amount of noise,
the type of ear protector, and the hearing status of the individual.
Ear protectors may cause medical problems in various ways. The materials from which the ear protectors are
made may cause allergic or toxic reactions. Cases of external otitis are rare when the material is inert, such as
neoprene, polyvinyl plastic or rubber. Stiff ear inserts may cause injuries if a blow on the ear causes the insert
to penetrate more deeply. Inserts with too tight a fit may contribute to barotrauma. Pressure-reducing ear
inserts are ineffective and should be avoided. Insertion of ear plugs may result in impacted cerumen in the ear
canal. Failure to keep ear protectors clean can result in disease. Ear protectors should not be worn when there
is existing external otitis or skin infection.
ICAO Preliminary Unedited Version — October 2008 III-12-13
HEARING TESTS AND FUNCTIONAL EXAMINATIONS
The examiner is actually testing the hearing throughout the examination. Questions should be asked in a low
voice and instructions given while the examinee has his back turned to the examiner. A few specific questions
whispered in alternate ears will give excellent leads as to the hearing ability.
The purpose of the hearing tests is to determine as nearly as possible the degree and type of any hearing loss
and functional impairment and to ascertain whether hearing function is satisfactory for the safe performance
of aviation duties as required in Annex 1. Hearing tests are useful for the diagnosis of certain diseases of the
ear and to separate disturbances of sound conduction from those of sound perception.
Hearing tests commonly employed include the use of whispered and spoken voice and tuning forks. These
methods yield much knowledge for the assessment of hearing if they are employed intelligently. However, the
results obtained are likely to be more qualitative than quantitative when assessed by inexperienced examiners.
Quantitative determinations are made with the electrically calibrated audiometer, which produces sound of
known intensity - either pure tone signals (at various frequencies) or actual speech (recorded or "live").
Whispered and spoken voice tests
The examiner who uses his voice to test an applicant's hearing must know how well his own voice is heard at
different distances and how to vary the intensity of his own voice so that each applicant is tested under similar
conditions. One can begin testing with a very low whisper, the lips about half a metre from the applicant's ear
and directed toward the ear. The examiner exhales and then whispers. In a quiet room an applicant with normal
hearing can repeat what is said to him. If he cannot understand a low whisper, the examiner uses a medium
whisper and finally a loud whisper. The examiner gradually increases the intensity of his voice until the
applicant responds correctly.
Hearing requirements for the issue and renewal of flight crew and air traffic controller licences in international
civil aviation are contained in Annex 1, Chapter 6, 6.3.4 - Hearing requirements (for Class 1 Medical
Assessment), 6.4.4 (for Class 2 Medical Assessment) and 6.5.4 (for Class 3 Medical Assessment). For Class
2 Medical Assessment, it is stated, inter alia, that the applicant must have the ability "to hear an average
conversational voice in a quiet room, using both ears, at a distance of 2 metres (6 feet) from the examiner, with
the back turned to the examiner."
Care must be taken in the choice of word material used to test hearing. Questions which can be answered by
"yes" or "no" should be avoided. It is better to have the applicant repeat familiar bisyllabic words (known as
"spondee5 words") such as snowball, cowboy and mousetrap or to ask a question such as "How many singers
constitute a quartet?" It is important to be certain that the applicant cannot read the examiner's lips.
Applicants with sensorineural hearing loss may hear a spoken voice much better than a whisper, even a loud
one. The reason is they tend to have a greater loss in high than in low frequencies and the whisper contains
more high frequencies than does the spoken voice.
Tuning fork tests
Tuning fork tests for hearing remain an important part of the hearing examination. The most useful tuning fork
for testing hearing is the 512 Hz fork. The examiner should understand and be able to do a Weber6 and a
5 Spondee: having two long syllables ( ⺷⺷ ⺷⺷ )
6 After Friedrich Eugen Weber, German otologist (1832–1891)
ICAO Preliminary Unedited Version — October 2008 III-12-14
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Manual of Civil Aviation Medicine 2(79)
