“The weather observer will check the co-pilot’s altimeter at frequent
intervals to insure that it is reading the same as the radar altimeter.
“All flights will depart storm area prior to sunset, regardless of the
degree of completion of the mission.
“Flight altitude while boxing the storm will be a minimum of five
hundred feet absolute altitude, or at such higher altitude as will
permit observations of the sea surface without hazard to safety. If
contact flight cannot be maintained at five hundred feet, the legs will
be flown a greater distance from the eye.”
The “boxing procedure” was used a great deal by the Air Weather Service
in the early years but by 1954 it had been eliminated. The
seven-hundred-millibar method was revised, and as used in flights out of
Bermuda in 1954 was described by Captain Ed Vrable, navigator, in part
as follows: “(1) The aircraft flies down wind at right angles to the
storm path to a point of lowest pressure, about twenty miles directly in
front of the eye; (2) Flight is continued down wind for three minutes
beyond the low point and then the heading of the aircraft is changed
135° to the left; (3) The aircraft continues on this course until the
pressure begins to rise and then turns 90° to the left and into the
center.”
This new Air Force plan of flying into the hurricane at seven hundred
millibars (ten thousand feet, roughly) is much like the Navy’s low-level
method, except that the Air Force crews enter down wind across the front
of the storm, but this is nearly always an advantage for aircraft based
at Bermuda. From that island their most direct approach to an oncoming
storm is into the front semicircle.
The Air Force has another aid in measuring weather in a storm. It is an
instrument called a “dropsonde,” a specially designed apparatus which
works on the same principle as the older “radiosonde.” A marvelously
ingenious instrument, the radiosonde is a unit of very small weight
containing miniature instruments for measuring pressure, temperature and
humidity. It also has a metering device, a battery, and a small radio
transmitter. The apparatus is carried aloft by a rubber balloon filled
with helium. As the balloon rises, the radio transmitter sends signals
for pressure, temperature and humidity at each level reached, and the
signals are copied on a register at the ground weather station.
The dropsonde is a radiosonde that is thrown out of the aircraft flying
at a high level, and allowed to descend by parachute, instead of being
carried up by a balloon. There is a special listening post in the plane,
where the data are recorded as the apparatus descends. The data are then
put into the form of a message for transmission by the plane’s radio
operator to the forecasting base. This work with the dropsonde is
usually done by the radar operator, in addition to his other duties.
Public-domain text, read in full here on John Shaqi.
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