High Angle Construction, Inc. — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1 200 New Jersey Ave. SE Washington, D.C. 20590 JUL 0 2 2010 Mr. Eric Lieberman President High Angle Construction, Inc. 11200 Donner Pass Road #126 Truckee, CA 96161 Ref. No. 10-0035 Dear Mr. Lieberman: This responds to your letter regarding the applicability of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-L80) to your helicopter-based avalanche mitigation company. Specifically, YOll ask whether the HMR apply to the Daisybell operation you describe that is used for avalanche control while suspended from a cargo-only helicopter. The Daisybell system utilizes two lead-acid batteries (24V) to power controlled explosions created by a compressed hydrogen and oxygen mixture. Gases are independently packaged in two hydrogen cylinders and one oxygen cylinder and are injected separately into an explosion chamber. The Daisybell system is activated while suspended 3-meters above the ground and the resulting explosion creates an overpressure of 80 millibars measured at ground level and for 12-meters horizontally. Under the conditions set forth in § 175.9(1), the avalanche control operations you describe using the Daisybel/ system are not subject to the HMR. The operational guidelines and handling procedures manual specified in § J75.9(t)(2) is, however, subject to approval by the Federal Aviation Administration's Principal Operations Inspector assigned to the operator. I trust this satisfies your inquiry. Please contact us if we can be of further assistance. Sincerely, ~ Hattie L. Mitcbell Chief, Regulatory Review and Reinvention Office of Hazardous Materials Standards#

Page 2High Angle Construction, Inc. General Engineering CA Lie. #654931 3iev~l1~ S'15· I U.S. DOT PHMSA Office of Hazardous Materials Standards ~1/S.c1 Attn: PHH-IO A/(( raf+East Building 1200 New Jersey Avenue, SE. Washington, DC 20590-0001 )0 -o()36 January 28, 2010 Re: Helicopter Based Avalanche Mitigation Dear Sirs: Several State Departments of Transportation, including the Utah Department of Transportation (UDOT), the Washington Department of Transportation (W ADOT), the Alaska Department of Transportation (AKDOT), and the Colorado Department of Transportation (CDOT), as well as certain helicopter skiing service providers and the Burlington Northern Santa Fe Railroad, currently contract with licensed Part 135 operators to conduct helicopter based avalanche mitigation procedures. These operations include the transportation and dispensation of assembled explosives from a helicopter and are completed in accordance with 49 CFR §175.9(t). UDOT, in conjunction with the Snowbird and Alta ski resorts and their local Part 135 helicopter operator, are considering the purchase of a new helicopter based system for the initiation and mitigation of avalanches for protection of roads and resort facilities. The device, called a Daisybell, mixes and then ignites hydrogen and oxygen gases from compressed gas cylinders attached to the device, in a steel, conical shaped vessel to produce a controlled pressure wave of air having sufficient force to trigger an avalanche. The Daisybell device is intended to be transported via Part 133 (External Load) and does not affect flight characteristics during operation. It is our understanding that, under §175.1, Purpose, Scope and Applicability, hazardous materials attached to or suspended from the helicopter is considered transportation in commerce. However, it is our belief that this type of operation, utilizing the Daisybell, can be accomplished in compliance with 49 CFR §17S.9(t). We would appreciate your confirming, at your earliest convenience, that the described Daisybell operations for mitigation of avalanche hazards falls under 49 CFR §175.9(t) so that these public and business entities can proceed with their plans to procure and deploy this new type of avalanche hazard mitigation system. 11200 Donner Pass Rd. #126, Truckee, CA 96161 Phone and fax: 5301 426-3226 E-mail: highangle@charter.net US Distributor for the Gazex Preventative Avalanche Release System#

Page 3High Angle Construction, Inc. General Engineering CA Lie. #654931 Please review the attached documentation for further infonnation and let me know if you have any questions. Thank. you for your anticipated cooperation. SinCe~elY yours, _--#---------~ Eric Liebennan, President 11200 Donner Pass Rd. # 126. Truckee. CA 96161 Phone and fax: 5301 426-3226 E-mail: highangle@charter.net US Distributor for the Gazex Preventative Avalanche Release System#