Guidance on kidney stones
Stones (calculi) may be found anywhere within the urinary tract (kidney, ureter, bladder and urethra). They vary in size, consistency, composition, shape and texture as do the internal dimensions of the renal tract. Movement of the stones is unpredictable, symptoms may occur abruptly and may be very severe. Severe pain, nausea and vomiting are produced by the stone impacting at a narrow area of the urinary tract. This is known as colic and may be renal (at the outlet of the kidney) or ureteric (in the tube between the kidney and the bladder). Pilots/ATCOs experiencing symptoms of renal stones are assessed as unfit.
The three-dimensional movements experienced during flight (particularly in turbulence or when pulling "G") may dislodge urinary stones. The pain can be incapacitating or distracting during flight. In addition, stones can also pass through the renal tract spontaneously.
Those who are stone-free or who have stones that are unlikely to move are permitted unrestricted certification, subject to surveillance. Approximately 30% of kidney stones recur after 10 years and almost 100% after 25-30 years. The early peaks of recurrence are at approximately 2 and 7 years.
The protocols for certification are given below.