* Experts perform reconnaissance mission on leaking rig
* Crew to proceed with "extreme caution" -Total
* Mild winds, mainly dry conditions forecast -MetOffice
By Oleg Vukmanovic and Henning Gloystein
ABERDEEN/LONDON, April 5 (Reuters) - French oil major Total said it was flying a team of crisis engineers to inspect a gas leak at its North Sea Elgin platform on Thursday with a view to eventually plugging the well.
Adverse weather conditions had prevented Total from sending a helicopter to the leaking rig earlier this week.
" Total confirms that a helicopter took off from Aberdeen at 10:30 am (0930 GMT) today with the objective of landing on the Elgin PUQ (process, utilities, quarters) to allow a specialised team to perform a reconnaissance mission of the Elgin wellhead platform and the G4 well, if it is safe to do so," a spokesman said, and added that the crew would "proceed with extreme caution".
Successful relief operations on the platform will also depend on weather conditions during the next few days.
The UK's MetOffice expected weather conditions around Aberdeen to be "mainly dry and rather cloudy, with still a little light rain mainly towards the Moray Coast", later on Thursday.
"It will be a milder night and winds will stay light," the MetOffice said.
For Friday it forecast conditions to be mainly dry, with light rains and maximum temperatures of 9 degrees Celsius.
Total said earlier this week that the team of engineers would assess conditions on the platform and find out whether a so-called "well kill" was feasible, by pumping mud into the well, and whether any other measures would be necessary.
Total said the gas leak is costing it $2.5 million a day.
Another, more expensive option being pursued in parallel is to dig two relief wells to the source of the gas at 4,000 metres depth, far below the sea bed.
Experts have said that option can take up to six months to complete, and Total has said it would push up daily costs to $3 million.
Total's share prices have dropped by almost 8 percent since the leak was reported last week, knocking over 7.5 billion euros ($9.8 billion) off its outstanding share value.
The crew of eight aboard the helicopter is a mix of staff from Total and Houston-based Wild Well Control.
Firefighters and engineers from the Houston-based company are experts at disasters such as oil rig explosions and have been dubbed "Hellfighters" by Hollywood.
The gas leak was reported on March 25 and is spewing an estimated 200,000 cubic metres of natural gas from the evacuated platform into the air per day, forming a highly explosive gas cloud around the platform.
It began after pressure rose in a well that had earlier been capped.
Two firefighting vessels remain on standby outside a two-mile exclusion zone around the Elgin platform, Total said.