Although many drilling rigs do not exceed 200 feet above ground level, they may be considered an obstruction where airways have low Minimum Obstruction Clearance Altitudes (MOCAs), in the vicinity of Instrument Approach Procedures (IAPs), or near hospital heliports and airports. It is the drilling company's responsibility to notify the FAA before they stand the mast. A TowerSAFE Airspace Analyst can tell you what needs to be done and handle the approval for you.
During periods of low visibility and icing conditions, pilots are sometimes forced to very low altitudes in order to stay out of icing conditions. It is important to have FAA approval for the Notice to Airmen (NOTAM) system to work and allow pilots to be aware of possible obstructions on their route of flight. Lighting may also be necessary.
Bad weather and low visibility make this rig a hazard