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Fixed Tank for Type IS-64 Helicopters
The Erickson Air-Crane Company has developed a fixed-tank firefighting system (See figure 1) for use with their Type I (large) S-64 model helicopters. This tank, of conventional aluminum construction, is mounted to the aircraft with eight hardpoint fittings, and can be installed in 30 to 45 minutes.
Tank capacities are 2,000 and 2,500 gal (7,571 and 9,464 L) for the S-64E and S-64F model helicopters, respectively. The tanks can be filled in 30 seconds from water sources as shallow as 18 in (457.2 mm). Filling the Type I tank is accomplished by a submersible pump permanently attached to the end of a 25-ft (7.62-m) inlet hose (snorkel).
The system is designed to be used with water, class A foam, or long-term retardants. An internal foam system carries 75 gal (283.9 L) of concentrate. In operation, the pilot determines the desired foam-to-water ratio, presses a button, and the foam is automatically injected. The tank's gating system is operated by the pilot, who selects one of eight flow rates and the quantity to be released. To initiate the drop, the pilot holds a button down until the drop is complete; or terminates it at any time by releasing the button. The gates are controlled automatically to assure accurate coverage levels by allowing the pilot to monitor the fluid level in the tank and the craft's ground speed.
Tanker No. 42, which is an S-64E incorporating this system, has been approved by the Interagency Air Tanker Board. Because the operating parameters of this helitanker are so different from those of large fixed-wing tankers, direct comparisons of cost per gallon delivered to the fire can be misleading. This unit was used on the Bend Complex Fires and the Marre Fire (Los Padres National Forest, CA, 1993). Field personnel have expressed satisfaction with its performance.
For further information about this tank, contact J.P. Johnston, national helicopter management specialist, at the National Interagency Fire Center, 3833 South Development Ave., Boise, ID 83705-5354; 208-387-5542; Fax: 208-387-5573; or Erickson Air-Crane Company, P.O. Box 3247, Central Point, OR 97502; 503-664-5544.
New Stronger Safety Gates for Leadline Hooks
As noted in the July 1993 Aviation Tech Tips 9357 1304-SDTDC "Helicopter Operations and External Accessories: An Update," a recurring problem exists with bent or distorted safety gates on leadline hooks, increasing the potential for inadvertent load releases. The safety gates currently in use are the stamped, sheet-metal type, and are typically damaged by either dropping the hook when attached to a ring, or allowing the load to apply a side force to the latch.
In response to the need for a more durable safety gate on leadline hooks, and the lack of available data on gate strengths, a number of hooks were selected for evaluation and testing at the San Dimas Technology and Development Center (SDTDC). Three hooks with improved styles of gates acceptable to a number of experienced helicopter operations specialists, plus the hook currently in use, were tested. A load was applied to the gate of each hook and was increased at a rate of 1/4-in per minute (6.35-mm per minute)-until the gate failed. The test results are shown in the following table:
| |
Side load |
Radial load |
| Hook make & model |
Breaking strength in lb (kg) |
Breaking strength in lb (kg) |
| Crosby R5-B Shur-Loc |
More than 5,770 (2,617) |
5,840 (2,649) |
| Gunnebo Grip Latch |
4,870 (2,209) |
1,590 ( 721.2) |
| Gunnebo NB-10 |
4,620 (2,096) |
1,200 ( 544.3) |
| Crosby R1-B |
2,675 (1,213) |
2,650 (1,202) |
| Crosby 320A (current style) |
140 ( 63.5) |
230 ( 104.3) |
These results clearly indicate that the gates on the selected hooks are much stronger than the current style. Based on this, and recommendations of the Helicopter Operations Specialists Committee, Forest Service Standard 5100-500e is being revised to specify a hook with these improved properties for leadline use.
New Helosafe Video
SDTDC recently produced a Helosafe training video, "The Professional Helicopter Pilot: Supporting Wildland Fire Suppression." This video introduces contract pilots, who are inexperienced in flying wildland fire missions, to the specialized aspects of these assignments and aspires to motivate all pilots to adopt an attitude of safety first. This video, the first of two, introduces common fire terms, describes a fire organization in detail, and provides information about some of the more common basic situations which are likely to arise. It introduces helicopter pilots to the unique circumstances of flying specialized natural resource missions for land management agencies. Copies can be ordered from the National Interagency Fire Center Warehouse, Boise, ID 83715-5428; 208-389-2542.
Bambi Bucket Control Head Update
On page 6, July 1993, Tech Tips No. 9357 1304-SDTDC1 we described several cases where the control head had failed under severe loadings-the causes of which were undefined. Field personnel let us know that the two failures in this area both occurred when the Bell 204/205/212 series helicopters landed on the buckets. This compresses the control head between the belly hook and the helipad. In one case, the helicopter crew had to dig the control head out of the ground with a shovel before the head was taken out of service.
The field report states that the overall length of the control head and hook exceed the distance between the ship's belly and the ground. Therefore, if the pilot does not set the bucket down while backing away, the control head easily can be jammed between the helicopter and the ground.
Improving Visibility of Remote Hooks
Many helicopter managers improve the visibility of their remote hooks with fluorescent paint; however, these paints lack durability. At the national meeting of Helicopter Operations Specialists (HOS) in Anaheim, CA, this past winter, a helicopter pilot experienced at longline logging offered a novel idea of placing a traffic cone above the remote hook. A technician made a hole in the top of a traffic cone large enough for a longline hook to fit through, and suspended the longline, cone, and remote hook from a tree (see figure 7). The idea is simple to adopt and should improve both the visibility of the hook and its longevity.
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For Additional Information Contact:
Aviation Program Leader
San Dimas Technology and Development Center
444 East Bonita Avenue, San Dimas CA 91773-3198
Phone 909-599-1267; TDD: 909-599-2357; FAX: 909-592-2309
E-mail: mailroom_wo_sdtdc@fs.fed.us
Information contained in this document has been developed for the guidance of employees of the Forest Service, United States Department of Agriculture (USDA), its contractors, and cooperating Federal and State agencies. The USDA assumes no responsibility for the interpretation or use of this information by other than its own employees. The use of trade, firm, or corporation names is for the information and convenience of the reader. Such use does not constitute an official evaluation, conclusion, recommendation, endorsement, or approval of any product or service to the exclusion of others that may be suitable.
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To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer.
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