Exhibit 21

PHI, Inc.

Subsidiaries of the Registrant at December 31, 2016

COMPANY |  | PLACE OF ORGANIZATION / INCORPORATION |  | % OF VOTING STOCK / MEMBERSHIP INTEREST OWNED |
Energy Risk, Ltd. |  | Bermuda |  |  | 100 | %
HELEX, LLC |  | Florida |  |  | 100 | %
PHI Tech Services, Inc. |  | Louisiana |  |  | 100 | %
Helicopter Management, LLC |  | Louisiana |  |  | 100 | %
Helicopter Leasing, LLC |  | Louisiana |  |  | 100 | %
AM Equity Holdings, L.L.C. |  | Louisiana |  |  | 100 | %
PHI Air Medical, L.L.C. |  | Louisiana |  |  | 100 | %
MDHL, LLC |  | Montana |  |  | 100 | %
Sky Leasing, LLC |  | Montana |  |  | 100 | %
Vertilease, LLC |  | Montana |  |  | 100 | %
Leasing Source, LLC |  | Montana |  |  | 100 | %
PHI Century Limited |  | Ghana |  |  | 49 | %
Personnel Outsourcing, Ltd. |  | Cayman |  |  | 49 | %
PHI Air Europe Limited |  | Cyprus |  |  | 49 | %
PHI Americas, Ltd. |  | Trinidad |  |  | 50 | %
PHI-HNZ Australia Pty Ltd. |  | Australia |  |  | 95.4 | %
TAC Leasing, LLC |  | Montana |  |  | 100 | %
VKA Leasing, LLC |  | Montana |  |  | 100 | %
GJW Leasing, LLC |  | Montana |  |  | 100 | %