Mr. Lyn Shenk

Branch Chief

Office of Transportation and Leisure

Division of Corporation Finance

U.S. Securities and Exchange Commission

100 F Street, N.E.

Washington, D.C. 20549

Commission File No. 001-00812

Form 10-K for the Fiscal Year Ended December 31, 2015

Filed on February 11, 2016

Staff Comment Letter Dated May 4, 2016

Request for Extension

Dear Mr. Shenk:

As discussed during a teleconference with Mr. Daniel Leslie on May 4, 2016, United Technologies Corporation hereby respectfully confirms that it will provide a response to the referenced Staff Comment Letter dated May 4, 2016 on or before May 27, 2016.  Please do not hesitate to contact me at (860)728-7000 if you have any questions.

Sincerely,

Peter J. Graber-Lipperman

Corporate Vice President, Secretary & Associate General Counsel

cc: Daniel Leslie (Division of Corporation Finance)

     Theresa Messinese (Division of Corporation Finance)