When replacing flare tips, the "long line" flying technique (sometime referred to as "Vertical Reference") is used. The great advantage with this method is that it allows the pilot to fly while looking down, using a bubble window in the helicopter. The pilot allways has a vertical view directly to the the platform and the load he is carrying. The technique involves the use of a 20 meter long lifting strop ensuring the helicopter is operating well above any danger area, and the helicopter downwash is minimized.
Another important factor is the use of customized guide and locking systems. Prior to removing the existing flare tips, all bolts and nuts are removed and special guide and locking devices are installed on each flange. These guides are fastened to the riser flange and have a spring loaded locking mechanism which keep the flare tips in a locked position even if all bolts are removed. For removing the existing flare tip, the locks are manually released by the installers at the flare platform, and the flare tip is lifted away. When installing the new flare tip, the guides are steering the load directly onto the flange and automathically lock the flare tip flange when it is in position.
Typical duration of a flare tip replacement operation will be from 6-10 hours, depending on the type and number of flare tips. This means the time from the installers enter the flare boom until all replacement work is completed.
An operation like described only involves a small group of personnel. Vertech Offshore crew consists of 3-4 mechanical installers and a supervisor. This crew need to be on the installation for 2 days. Helicopter crew (3 persons) arrive on the platform in the morning on the operation day and leave immediately after completion of the work.