AIM

4/20/23

10

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Special Operations

a written description of the hazard, time and duration of occurrence, and other pertinent information. ANY
POTENTIAL HAZARD should be communicated to helicopter operators or company aviation departments as
early as possible to allow the NOTAM to be activated.

(c)

To supplement the existing NOTAM procedure and further assist in reducing these hazards, a

standardized visual signal(s) on the helideck/heliport will provide a positive indication to an approaching
helicopter of the status of the landing area. Recommended Practice(s) have been developed to reinforce the
NOTAM procedures and standardize visual signals.

f. Drilling Rig Perforating Operations: Helideck/Heliport Operational Hazard

Warning(s)/Procedure(s)

1. Background.

A critical step in the oil well completion process is perforation, which involves the use

of explosive charges in the drill pipe to open the pipe to oil or gas deposits. Explosive charges used in conjunction
with perforation operations offshore can potentially be prematurely detonated by radio 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 Air Missions (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 subparagraph 10

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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

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1.)

(3)

The marker should be installed during the time that charges may be affected by radio transmissions.

(b) Pilots

(1)

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, pilots 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, ADS

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B equipment,

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

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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.