In my opinion you should stay well clear. By the description you have provided, it will be in direct support of and is being requested by a commercial operation for commercial purposes. Renumeration financially or not, it is a standby emergency helicopter, which is not pleasure flying for private purposes.
There are a whole host of other issues, legal and practical that make this very dodgy ground. Do you hold a license that allows you to fly in that country? Do you have all the relevant training and experience to operate in the desert with passengers on board? Is the helicopter certified for patient transport?
Without wanting to sound condescending, there is no such thing as a “simple helicopter for emergency standby”. It is a complex operation that needs correct supervision, planning and support. It is fraught with risk that you are clearly not fully aware of, and needs to be well planned and executed by experienced personnel. Even if you hold a CPL, I would suggest to operate in such a fashion you will need an AOC that encompasses some form of Special Operations in the Ops Manual such as HEMS or Ambulance flying as well as maintenance procedures for basing a helicopter in the field.
If the company needs an emergency helicopter on standby and it has been highlighted in the risk assessment of the operation, they need to pay for it. There will be undoubtedly local companies that can provide this. The local CAA needs to be informed and I suggest they will not allow such an operation. By not informing them, I would expect that if you arrive unannounced as an unregistered ambulance at a hospital in town with a helicopter, the sh!t would start to roll.
Bottom line - this is a commercial operation and must be treated as such, not just with regards to licensing but also to registration and legality of the company providing this.
Last edited by 26500lbs; 27th Dec 2015 at 14:09.