Exhibit 15.1

September 27, 2019

Securities and Exchange Commission

100 F Street, N.E.

Washington, DC 20549

Commissioners:

We are aware that our reportsdated April 25, 2019 and July 25, 2019 on our reviewsof interim financial information of Raytheon Company (the “Company”), which appear in this Current Report on Form 8-K,  are incorporated by reference in the Registration Statements on Form S-8 (Nos. 333-228649, 333-225839, 333-207193, 333-197704, 333-183123, 333-177517, 333-175781, 333-150643, 333-125293, 333-110020, 333-100724, 333-100723, 333-100718 and 033-51385) of United Technologies Corporation.

Very truly yours,

/s/ PricewaterhouseCoopers LLP

PricewaterhouseCoopers LLP

Boston, Massachusetts

September 27, 2019