EX-5.1

We have acted as counsel to APX Group, Inc., a Delaware corporation (the “Company”), APX Group Holdings, Inc., a Delaware corporation (the “Parent Guarantor”) and the subsidiaries of the Company listed on Schedule I hereto (together with the Parent Guarantor, the “Guarantors”) in connection with the Registration Statement on Form S-4 (the “Registration Statement”) filed by the Company and the Guarantors with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended, relating to the issuance by the Company of up to of $925,000,000 aggregate principal amount of 6.375% Senior Secured Notes due 2019 (the “Exchange 2019 Securities”) and up to $580,000,000 aggregate principal amount of 8.75% Senior Notes due 2020 (the “Exchange 2020 Securities” and, together with the Exchange 2019 Securities, the “Exchange Securities”) and the issuance by the Guarantors of guarantees (the “Guarantees”) with respect to the Exchange Securities. The Exchange 2019 Securities and the Guarantees thereof will be issued under an Indenture, dated as of November 16, 2012 (as amended to the date hereof, the “Exchange 2019 Securities

Indenture”) among the Company, the guarantors named therein and Wilmington Trust, National Association, as trustee (in such capacity, the “Exchange 2019 Securities Trustee”), and the Exchange 2020 Securities and the Guarantees thereof will be issued under an Indenture, dated as of November 16, 2012 (as amended to the date hereof, the “Exchange 2020 Securities Indenture” and, together with the Exchange 2019 Securities Indenture, the “Indentures,”), among the Company, the guarantors named therein and Wilmington Trust, National Association, as trustee (in such capacity, the “Exchange 2020 Securities Trustee” and, together with the Exchange 2019 Securities Trustee, the “Trustees”). The 2019 Exchange Securities will be offered by the Company in exchange (the “Exchange”) for $925,000,000 aggregate principal amount of its outstanding 6.375% Senior Secured Notes due 2019 and the Exchange 2020 Securities will be offered in exchange for $580,000,000 aggregate principal amount of its 8.75% Senior Notes due 2020.

We have examined the Registration Statement and the Indentures (including the forms of Exchange Security set forth therein), which have been filed with the Commission as exhibits to the Registration Statement. We also have examined the originals, or duplicates or certified or conformed copies, of such records, agreements, documents and other instruments and have made such other investigations as we have deemed relevant and necessary in connection with the opinions hereinafter set forth. As to questions of fact material to this opinion, we have relied upon certificates or comparable documents of public officials and of officers and representatives of the Company and the Guarantors.

In rendering the opinions set forth below, we have assumed the genuineness of all signatures, the legal capacity of natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as duplicates or certified or conformed copies and the authenticity of the originals of such latter documents. We also have assumed that the each of the Indentures is the valid and legally binding obligation of the applicable Trustee.

We have assumed further that each of 313 Aviation, LLC, ARM Security, Inc., Vivint, Inc. and Vivint Purchasing, LLC (collectively, the “Utah Guarantors”) has duly authorized, executed and delivered

the Indenture in accordance with the law of Utah and (2) execution, delivery and performance by the Utah Guarantors of the Indenture and the Guarantees do not and will not violate the law of Utah or any other applicable law (excepting the law of the State of New York and the federal laws of the United States).

Based upon the foregoing, and subject to the qualifications, assumptions and limitations stated herein, we are of the opinion that:

1. When the Exchange Securities have been duly executed, authenticated, issued and delivered in accordance with the provisions of the applicable Indenture upon the Exchange, the Exchange Securities will constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their terms.

2. When (a) the Exchange Securities have been duly executed, authenticated, issued and delivered in accordance with the provisions of the applicable Indenture upon the Exchange and (b) the Guarantees have been duly issued, the Guarantees will constitute valid and legally binding obligations of the Guarantors enforceable against the Guarantors in accordance with their terms.

Our opinions set forth above are subject to (i) the effects of bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium and other similar laws relating to or affecting creditors’ rights generally, (ii) general equitable principles (whether considered in a proceeding in equity or at law) and (iii) an implied covenant of good faith and fair dealing.

We do not express any opinion herein concerning any law other than the law of the State of New York, the federal law of the United States, the Delaware General Corporation Law and the Delaware Limited Liability Company Act.

We hereby consent to the filing of this opinion letter as Exhibit 5 to the Registration Statement and to the use of our name under the caption “Legal Matters” in the Prospectus included in the Registration Statement.

Very truly yours,

SIMPSON THACHER & BARTLETT LLP

/s/ Simpson Thacher & Bartlett LLP


Subsidiary		Jurisdiction of Organization
313 Aviation, LLC		Utah
ARM Security, Inc.		Utah
Vivint, Inc.		Utah
Vivint Purchasing, LLC		Utah
AP AL LLC		Delaware
Vivint Wireless, Inc.		Delaware


APX Group, Inc		September 12, 2013


APX Group, Inc		September 12, 2013