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AIM

10/12/17

10

−2−3

Special Operations

transmissions, including those from helicopters. The
following practices are recommended.

2. Recommended Practices

(a) Personnel Conducting Perforating

Operations.

Whenever perforating operations are

scheduled and operators are concerned that radio
transmissions from helicopters in the vicinity may
jeopardize the operation, personnel conducting
perforating operations should take the following
precautionary measures:

(1)

Notify company aviation departments,

helicopter operators or bases, and nearby manned
platforms of the pending perforation operation so the
Notice to Airmen (NOTAM) system can be activated
for the perforation operation and the temporary
helideck closure.

(2)

Close the deck and make the radio

warning clearly visible to passing pilots, install a
temporary marking (described in subpara-
graph 10

−2−1i1(b)) with the words “NO RADIO”

stenciled in red on the legs of the diagonals. The
letters should be 24 inches high and 12 inches wide.
(See FIG 10

−2−1.)

(3)

The marker should be installed during

the time that charges may be affected by radio
transmissions.

(b) Pilots

(1)

Pilots when operating within 1,000 feet

of a known perforation operation or observing the
white X with red “NO RADIO” warning indicating
perforation operations are underway will avoid radio
transmissions from or near the helideck (within
1,000 feet) and will not land on the deck if the X is
present. In addition to communications radios, radio
transmissions are also emitted by aircraft radar,

transponders, radar altimeters, and DME equipment,
and ELTs.

(2)

Whenever possible, make radio calls to

the platform being approached or to the Flight
Following Communications Center at least one mile
out on approach. Ensure all communications are
complete outside the 1,000 foot hazard distance. If no
response is received, or if the platform is not radio
equipped, further radio transmissions should not be
made until visual contact with the deck indicates it is
open for operation (no white “X”).

g. Hydrogen Sulfide Gas Helideck/Heliport

Operational Hazard Warning(s)/Procedures

1. Background.

Hydrogen sulfide (H

2

S) gas:

Hydrogen sulfide gas in higher concentrations
(300

−500 ppm) can cause loss of consciousness

within a few seconds and presents a hazard to pilots
on/near offshore helidecks. When operating in
offshore areas that have been identified to have
concentrations of hydrogen sulfide gas, the following
practices are recommended.

2. Recommended Practices

(a) Pilots

(1)

Ensure approved protective air packs

are available for emergency use by the crew on the
helicopter.

(2)

If shutdown on a helideck, request the

supervisor in charge provide a briefing on location of
protective equipment and safety procedures.

(3)

If while flying near a helideck and the

visual red beacon alarm is observed or an unusually
strong odor of “rotten eggs” is detected, immediately
don the protective air pack, exit to an area upwind,
and notify the suspected source field of the hazard.

FIG 10

−2−1

Closed Helideck Marking 

− No Radio