Helicopter guidelines for land seismic & helirig operations - OGP

Helicopter guidelines for land seismic & helirig operations
F.4 Line helipads in forest or jungle areas
The work involved in clearing trees, primary or secondary forest/jungle, even to 1m level is
considerable and the removal of tree trunks is unlikely to be achieved with the resources of a
helicopter supported seismic party. In order to achieve a flat area, clear of immediate obstructions
allowing transition between the hover and forward flight, it will often be convenient, especially in
areas prone to flooding, to construct a raised helipad. However, the rate of decay and destruction
by insects of softwoods in tropical climates should not be underestimated. Whenever raised
wooden helipads are used, the following procedure is recommended:
1. Upon first construction: inspection and release to service by the senior pilot (that will also
include a check of the entire clearing for correct dimensions and freedom from obstructions).
2. Two months from construction: inspection by a ground party who may be brought in
by helicopter provided the pilot is briefed and able to keep the helicopter light on the
undercarriage. Subject to findings during this check, the landing site may be released to
service for a further month.
3. Three months from construction: complete rebuild of elevated helicopter landing platform
and pre-release inspection.
For more permanent landing sites consideration should be given to using hardwood planks;
the structure, which will also be subject to a three month inspection interval, may be repaired
on condition. Should the seismic campaign run into a drilling campaign, then all pads to be
used by rig support aircraft should be constructed of hardwood. Used engine oil has been found
effective as a hardwood preservative, and using this method, no deterioration was noticed after
eight months. However, should oil be used as a preservative then due attention will have to be
paid to ensure the environment is not contaminated during the application of the oil.
When short sling loads are to be handled in standard clearings, it is essential that an area free
of obstruction, of approximately 5 meters square and above the level of stumps/felled trees, be
made available. Although the landing area may be used for this purpose, in order that loads may
be prepositioned without prejudicing the ability to land a helicopter with passenger or internal
loads, it has been found convenient to prepare secondary pads, displaced at least 5 meters from
the main landing area.
Fly camps should be set up well inside the tree line so as not to intrude into the cleared area. This
serves to avoid the danger from falling trees rendered unstable by the clearing process, and to
distance tarpaulins and other loose camp equipment from the rotor downwash, which may lift
items into blades or engine intakes with disastrous results. It will also protect personnel from
the danger of flying debris in the event of a helicopter crash landing at the helipad.
It is also essential to brief personnel not to set up the fly camp in the area directly under the
approach and overshoot flight path since in the event of an engine malfunction during sling
operations the pilot will release the load to gain additional performance from the helicopter.
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