Haw. Rev. Stat. § 261E-18
(a) Unless otherwise provided in this chapter, all hearings, investigations, and proceedings shall be governed by chapter 91 and by rules adopted by the air carrier commission, and in the conduct thereof, the rules of evidence need not be applied; provided that in all evidentiary hearings conducted pursuant to chapter 91 in which a person has the burden of:
(3) Proving the reasonableness of expenditures, contracts, leases, or other transactions between the carrier and corporate affiliates of the carrier,
the burden shall be satisfied only if the reliable, probative, and substantial evidence is clear and convincing. No informality in any hearing, investigation, or proceeding, or in the manner of taking testimony shall invalidate any order, decision, or rule made, approved, or confirmed by the commission.
[L Sp 2008, c 1, pt of §2]