N.H. Rev. Stat. § 422-B:9
When the department determines that a structure is a hazard or a potential hazard to air navigation within the meaning of this chapter, it shall notify the owner of the land on which the structure is located or the owner or operator of the structure. The notice shall be in writing and shall set forth specifications as to the manner in which the structure is to be marked, illuminated, painted or designated in order to make it clearly visible to airmen. The person to whom the notice is sent shall have 60 days to comply with the requirements thereof. Such determination shall become final 20 days after notification thereof is received unless the person receiving such notice requests in writing, within such 20-day period, that a hearing be held before the department with reference to the determination. All such hearings shall be open to the public. Any person interested may appear and be heard either in person or by counsel and may present such evidence and testimony as may be pertinent.
RSA 422-B:9
1959, 118:1. 1985, 402:6, I(c)(2).