Udhamsingh Nagar District Magistrate B K Sant ordered the inquiry after taking note of a complaint by BJP leaders, who alleged that administration "deliberately" delayed the landing by more than 3 hours yesterday.
Malini's helicopter had landed at Sitarganj where she addressed a public meeting in favour of BJP candidate Prakash Pant and asked the people to vote for him on July 8 bypoll.
Pant is contesting the byelection against Uttarakhand Chief Minister Vijay Bahuguna, a Lok Sabha member from Tehri, who needs to be elected as a state legislator before completion of six months in office to continue as the chief minister. He completes his six months in office on September 13.
The vacancy was created following the resignation of BJP MLA from Sitarganj, Kiran Mandal, who joined the Congress amid allegations of horse trading.