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Hank Sloan, Logging Engineer USFS National Forests of Virginia 5162 Valleypointe Parkway Roanoke, VA 24019

John Tollenaere, KMAX Operations Manager Chris Croff, KMAX Operations Consultant Kaman Corporation Bloomfield, CT 06002


A shift level production and cost analysis of helicopter yarding with the new Kaman Aerospace K-MAX ship in Appalachian hardwoods is presented. Kaman has designed a new ship specifically designed for external lift operations with logging as a primary end use. This design utilizes dual counter rotating intermeshed main rotors with no tail rotor. The objective of the K-MAX design is to significantly lower helilogging costs in order to be cost competitive with other logging systems. This medium lift (6000#) aerial truck has many features which facilitate helilogging. Although no history is available (1994) on the K-MAX for maintenance costs and availability, projections have been made which indicate helilogging costs to be between $140 and $190/MBF (Int 1/4") for yarding an average distance of 1900 ft in a gypsy moth salvage of primarily Oak species. Recommendations are presented to improve helilogging operations in Appalachian hardwoods, and to assist in helicopter sale design and layout.

KEYWORDS: Helilogging, Appalachian Hardwoods, Salvage, Gypsy Moth, Helicopter Logging


Presented at:



This case study was conducted March 1-9, 1994 on the Jefferson National Forest in Virginia. The project involves the shelterwood treatment of 46 acres of Appalachian cove hardwoods to improve the health and vigor of the remaining live forest impacted by Gypsy Moth defoliation in 1991. The objective of the treatment was to promote regeneration and to salvage the dead and dying trees to provide wood and fiber to meet societies' needs. Due to the unacceptable environmental impacts of using conventional ground based systems, helilogging methods were used. The results of this case study will help in determining the costs and limitations of this new technology in Appalachian hardwoods. With significant reductions in helilogging costs it is possible to promote this method for widespread salvage of dead and dying Appalachian forest, and provide a mechanism to pretreat currently inaccessible stands to better withstand the stress of Gypsy Moth defoliation.

This project began during May of 1993 in discussions with Mr. John Tollenaere of Kaman Corporation. Kaman wanted to hold an engineering evaluation of the KMAX helicopter on a timber sale which required Helicopter logging. The Jefferson National Forest was interested in promoting the use of helicopter logging, and in cooperating with Kaman to determine operating characteristics of this particular ship. It was hoped that a ship of this size could be utilized to efficiently harvest our Appalachian hardwoods. After a review of several potential sites, the Hunting Creek area on the Glenwood Ranger District was selected for this project. The environmental documents were written and a District Ranger decision was issued. This decision was appealed to the Forest Supervisor by two preservation oriented special interest groups. After review of the projects environmental records and analysis, the Forest Supervisor affirmed the District Rangers' decision. This decision was then appealed to the Regional Forester. After Regional Office review of the projects environmental records and analysis, the Regional Forester affirmed the decision to proceed with the project. This process of clearing the project for implementation was concluded in late January of 1994, some 8 months after beginning the environmental analysis and documentation requirements of the Forest Service's implementation of the National Environmental Policy Act.



The Hunting Creek Helicopter timber sale (Figure 1) was then marked and advertised for bidding on January 27, 1994. The sale contained 100 mbf of Chestnut Oak and 149 mbf of Northern Red Oak for a total tree measured volume of 249 mbf (International 1/4" scale). On February 25 bids were opened and Kaman Aerospace Corporation was the sole bidder. The contract rates were $31.50/mbf on the Chestnut Oak and $222.00/mbf on the Northern Red Oak, for a total bid of $36,228.00. The contract was executed that day, all payments were wire transferred in, and the payment unit was released for cutting. Kaman Corporation hired a consultant, Mr. Chris Croff, to be their purchaser representative on the sale. Mr. Croff is experienced in helilogging operations and was instrumental in all the coordination and arrangements that are essential to this successful helilogging show. That afternoon felling and bucking began and continued throughout the weekend. Log landing construction began, the service landing was arranged and move in of all support equipment was complete by February 28. Flying began on the afternoon of February 28 with some test lifts and the logging was completed on March 8, loosing two days March 2/3 where no flying occurred due to an ice storm.

All of the timber was felled and bucked for a target 5000 pound payload. Density of the timber was determined by weighing logs at a local sawmill and computing the volume of the logs using the average end area times the length, averaging 70lbs/ft3. The cutting crew, consisting of 4-5 faller/buckers, had never cut for a helicopter show. A piece size chart using log scale diameter and length was developed for the target 5000 pound load, and instructions given to the fallers. Due to the variations in form and density experienced in Appalachian hardwoods, and oak in particular, it is difficult to buck to a precise payload. This is a key area, turn building to payload, in which helilogging productivity gains can be made by improving the consistency of turn weights. However since an engineering evaluation of the ship was the primary objective, and not a demonstration in helilogging, load efficiency concerns were secondary in importance to the operation. Hooking was accomplished with 14 foot nylon double eyed straps. The hooking operation was alternated between two, two man crews. The subcontract hooking crew was from an experienced Montana helilogging operator. The KMAX ship ran a 150 foot tagline and the ship itself was heavily instrumented for the purpose of collecting engineering data which Kaman will use to refine and verify the ships' design. Experienced pilots for the operation were brought in from Erickson Skycrane and Skyline Helicopters, both helilogging contractors from the state of Washington. Flight distance from the 46 acre unit to the landing (elevation 2400') ranged from 500 to 2600 horizontal feet, with the average approximately 1900 feet. The cut volume per acre was 5.4 mbf. One of the main factors in a quick cycle time in helilogging is the ability of the pilot to see the hookers on the ground. For this reason, when logging Appalachian hardwoods, it is important to log in the leaf off season. Cut volume per acre must be such that the canopy is opened up enough to permit the drop hook to descend to ground level without getting hung in the standing trees. Visibility and drop hook hangups were not a problem. Total turn times ran from 2.2 to 3.0 minutes daily average, with a fuel cycle of from 60 to 75 minutes. Turn times included an average 90 ft vertical lift in winds from calm to 20 knots, temperatures ranging from 32 to 70 degrees (F), and hook point elevations from 2300 to 2900 ft. The service landing was located 3.2 miles away from the log landing on private property and consisted of a marked helispot and a fuel truck. The planned operating hours were from 9:30 to 11:30 am and from 1:30 to 3:30 pm. This schedule also included times for special shows, such as the longline lifting and placement of a 3.0 ton Army generator for a military group viewing the operations.

Once the turn hit the landing, C&N Logging from Natural Bridge, Virginia took over as the subcontractors responsible for all ground work exclusive of the hooking. Although C&N Logging had never worked with helicopter logging it is a very experienced production oriented logging company headed up by two brothers, Jack and Lester Campbell. They decided to run the landing hot, by taking all landed material directly to the knuckleboom loader for truck loading and haul. Their philosophy was, why handle the material twice (in and out of a cold deck) when their production rate of loading and hauling could keep up with the yarding. In addition they wanted to utilize a buck saw instead of manual bucking with chain saws. Back up plans were to extend the landing and allow for cold decking with manual bucking, as is more typical of a helilogging landing. A new Caterpillar 916 rubber-tired front end log loader, a new Peerless 2170B knuckleboom equipped with a CTR bucksaw and one chaser manned the log landing. The Campbells proved correct in their planned support operations, however on Saturday 3/5 they hot logged 13 trailer loads off the landing and Jack said that they were pushed pretty hard and probably could not have handled any more. The cold deck area did not have to be built, and the landing size was kept to a minimum (1/4 ac).

Overall the operation went quite smoothly considering the objectives of Kaman Aerospace, the fact that this was the first sale requiring helicopter logging on the Jefferson National Forest, and that the sale was ground supported by a logging company that had never worked with helilogging.


Actual yarding time for the sale was 42.1 productive hours to yard the 249 mbf (International 1/4" scale). This productive time, which includes the refueling time, was high due to the service landing being located an abnormally long 3.2 miles from the log landing. This yields a productive rate of 5.91 mbf/hr. John Tollenaere from Kaman Operations has estimated the cost of operating the KMAX to be $1,713/hr at an annual usage rate of 1000 hours and $1,324/hr at an annual usage rate of 1500 hours (See Appendix for cost detail). Since the KMAX has no service history, these operating costs have been estimated based on a conservative approach in consultation with helicopter logging contractors. These costs represent a reasonable model of what can be expected for acquisition, maintenance, insurance, fuel, office support, and crew support. The economies of scale are evident in higher annual usage, since a majority of the costs are fixed in relation to an independent contractor. Based upon the sale volume, the productive hours of flight, and the estimated hourly operating costs, the range of yarding costs actually experienced in this evaluation were between $290 and $224 per mbf to go from stump to landing. These actual unit costs are somewhat higher than those commonly experienced by helilogging contractors. Several factors played a role in these high unit costs. Table 1 summarizes the production data for the Hunting Creek Helicopter evaluation. The volume/day data is a summary of the mill scale tickets as trucked on a daily basis. Since the sale was hot logged, it is felt that the daily trucked volume is close to the daily yarded volume. The volumes have also been adjusted for conversion to International 1/4" scale and an estimated production of eight loads for which mill scale tickets were unavailable.

Table 1. Summary of KMAX Yarding the Hunting Creek Sale
Date Yarding Cycles Turns Flight Time, hrs Min/Turn Mbf Mbf/hr
3/1 4 85 4.2 3.0 17.6 4.2
3/4 5 157 6.7 2.6 26.2 3.9
3/5 7 219 7.9 2.2 53.4 6.8
3/6 6 191 7.4 2.3 40.5 5.5
3/7 6 177 7.6 2.6 48.5 6.4
3/8 7 n/a 8.3 n/a 62.8 7.6
Total/Avg 35 n/a 42.1 2.4 249.0 5.9

The operational factors which were particular to this engineering evaluation and lead to high unit rate yarding costs were:

1) poor load efficiency

2) extended distance to service landing

3) heavy instrumentation of prototype ship and associated data collection efforts

4) pilot inexperience with the KMAX (learning curve)

5) hooker/faller/bucker inexperience with the turn weight estimation leading to overweight aborts and skid turns to bunch for payload

6) inexperience by the Forest Service in laying out helicopter sales resulting in excessive time yarding scattered pieces

7) reduction in sale volume as a result of preservationists appeals which resulted in sparse areas of designated timber (361mbf originally marked reduced to 249mbf).

The impacts of these factors on the unit costs need to be evaluated in order to project what costs might be expected in a production logging situation. The load efficiency on this study was 3540# average weight per turn (range from 2000# to 6400#) divided by 6000# lift capacity, or 59%. Load efficiencies common in the helilogging industry are 80%. The distance to the service landing is normally within close proximity to the log landing. The estimated additional time spent in route was 6 minutes per fuel cycle over the 29 cycles resulted in 2.9 hours additional productive time due to excessive (>.5 mile) distance to the service landing. The instrument package which was on board the ship weighed 300# and required some time at the end of each fuel cycle to download data. It is uncertain how much time was spent, and the weight of the data package contributed to the poor load factor. While both the pilots were experienced in helilogging, the KMAX was a new ship for them to fly. Probably the most reliable factor with the pilot learning curve was the increasing fuel rate as the pilot got used to the ship. The last three days of productive logging were accomplished by the same pilot. During this time the fuel rate increased from 80 gallons/hr to 84 gallons/hr average. It is felt that this increase in fuel consumption is attributable to the pilot's comfort factor and learning how to work the ship harder. This would represent a 5% increase in productivity. Table 1 shows an increase in productivity over these last three days despite an increasing amount of scattered turns to clean up the sale to meet utilization requirements. This also indicates a learning curve effect. The rate of aborted/skid turns averaged 6.3% over a three day period towards the end of the evaluation period. It is felt that with a more experienced crew in turn building that this rate could be cut in half increasing productivity by 3%. Since this was the first helicopter sale on the Glenwood RD, there were some improvements in sale layout that could have been made. The most significant factor was the last minute reduction of sale volume to 70% of the original marked volume due to preservationist appeal concerns. This resulted in the marked volume being light in areas, and left no flexibility in the building of turns for payload. Additionally, there was very little thought put into the what minimum sawtimber tree specifications and piece sizes should be used to facilitate the economics of helicopter logging. These considerations in sale prep would have led to a higher load factor than that experienced.

To account for these factors the following adjustments are suggested in productivity to get a better look at what productivity and unit costs might be experienced in a commercial operation.

Load Factor to 80% 5.91 x 1.36 = 8.04 mbf/hr

Service Landing distance 8.04 x 1.07 = 8.60 mbf/hr

Learning Curve 8.60 x 1.05 = 9.03 mbf/hr

Abort/Skid Turn Rate 9.03 x 1.03 = 9.30 mbf/hr

If these adjustments are not made individually, then the adjusted production rate is 5.91 x 1.51 = 8.92 mbf/hr. Given these considerations, a reasonable adjusted productive rate should be between 9.0 and 9.3 mbf/hr for similar logging conditions.

Using the same hourly costs the range in unit rates would be from $1713/9.0 = $190/mbf to $1324/9.3 = $142/mbf. These costs would not include mobilization nor profit.

Table 2. Projected Production and Yarding Costs for KMAX Evaluation Hunting Creek Timber Sale
MBF/hr (Int 1/4)
$/MBF (Int 1/4)
1000 9.0 1713 190
1000 9.3 1713 184
1500 9.0 1324 147
1500 9.3 1324 142


Appalachian hardwoods are heavy and inconsistent as to their density. This is a major problem and needs to be dealt with much in advance of the ship arriving. It is inconsistent to estimate tree weights based upon board foot scale or scaling diameter due to the variations in density and the lack of consideration of piece taper. It has been suggested in the past that the midpoint diameter (area) of a piece times the piece length times a density is the best way to estimate tree weight (Dale Waddell, 1989). This method is recommended for future helilogging operations in Appalachian hardwoods. A range and mean of densities specific to tree species can be developed from core samples. The following represents an example of such a table.

Table 3. Estimated weight of Northern Red Oak logs.
Contact for details of Table 3

After observing the extreme importance of average load factor in determining unit costs, a system for improving this skill is being suggested. In developing turns for a specific payload, it is suggested that a two pass system be used. The first pass is to directionally fell the tree, limb, and top to merchantable height. The second pass is to develop the turns through bucking. In this manner, felling production would not be slowed by teaching a new technique, and turn building expertise could be concentrated where it will be most effective. During the second pass, the turn builder can estimate the density based upon an estimate of growth ring count and species. The turn builder then needs to estimate the probable hook drop point. From that point the turn builder then estimates the total number of turns from that point within single or double strap length, as the situation warrants. The bucking can then be done to make up pieces for each turn to get payload. The turn builder will need to acquire skill at estimating length and diameters. A Biltmore stick with the weights of pieces printed on it would be most helpful.

This same process of turn building needs to be accomplished during sale design and layout, except based upon Diameter Breast Height (DBH), form class, and merchantable height. The designation of timber to be cut should consider the opportunity to remove full payloads for the design helicopter. This consideration should be in the form of a minimum cut per acre and the minimum tree and piece specifications to be cut and removed.

Minimum cuts per acre on helilogging operations have been suggested in the past. (40-60m3/ha;J.C.Halkett, 1982). In logging with a KMAX the designed payload is 5000#. The idea would be to provide a minimum cut per acre which would allow for the opportunity to build full payload. Utilizing table 1 as a guide to weight, a 16' log with a 18" midpoint would run from 1900 to 2200 pounds. Given a standard taper allowance of 1/2" per 4' section yields a scaling diameter of 17" and 210 board feet (International 1/4" scale). This yields a 9 to 10.5 pounds per board foot density. If a given drop point would service a 50 foot radius area (.18 ac), then the marked volume should be as follows:

5000#/(9#/bf*.18ac) = 3.1 mbf/ac to

5000#/(10.5#/bf*.18ac) = 2.6 mbf/ac

Therefore it follows that a 2.5 to 3 mbf/ac International 1/4" should be the lowest volume per acre cut considered for the KMAX. As a practical guideline, some additional payload capacity should be available to assist in turn building. Marking guidelines should be developed to reach these minimum volumes. A simple method has been developed to estimate the volume per acre for Appalachian hardwoods and the prism. (Ashley,B.S.1991) Using a 10 factor prism, counting all the logs in the plot and multiplying by 650 yields Bf/Ac. Therefore, marking guidelines could be such that at least 4-6 merchantable logs in a 10 factor plot need to be marked. Similar guidelines could be developed for fixed radius plots. These logs must meet or exceed a minimum specification in order to be merchantable, which will vary primarily on the market value of the log.

In addition to the minimum volume per acre, serious evaluation of the minimum tree specifications to be marked, and the minimum piece specification for utilization needs to be considered. Due to the high operating costs of helicopters, there is very little opportunity to remove trees which do not bring a positive cash flow for the purchaser. It is suggested that price lists from probable open market sawmills in the sale area be obtained and that no timber marked or pieces required to be removed which do not cover estimated development costs. In this particular case, with total development costs estimated at $280 - $300/mbf Doyle, only Forest Service grade 1 and better Red Oak, Chestnut Oak, Ash, and Yellow Poplar should have been marked. The minimum piece size should have been 12" dib and 10 ft. These utilization factors need to be considered on a case by case basis, if a successful helicopter logging program is to be established. The National Forests of Virginia have the timber resource to support a modest program of timber sales meeting these requirements.

Since Appalachian hardwoods are heavy (65-70 #/ft3) there is a significant assignment of risk to the helilogging subcontractor to contract yard on a per mbf basis. Perhaps a more equitable arrangement could be made if the helilogging were to be contracted out on a per ton basis. This would place more risk on the manufacturer of the logs who is, with varying utilization and manufactured specifications, in a better position to assume this risk. The ship and all the supporting equipment do not perform on the variances in log scaling practices. They do however perform based upon tonnage flown. It is expected that very little difference would occur in unit costs of flying tons of Douglas Fir or flying tons of Northern Red Oak under similar sale conditions. This would permit the helilogging contractor to focus on the tonnage produced and ease the burden of carrying products that do not pay for themselves on the open market. Significant change would have to occur in order for this recommendation to happen, as no Appalachian hardwood mills are currently buying quality logs on a ton basis.




KMAX Estimated Operating Cost Detail (Cash Flow Basis)

Item 1000 hr/yr 1500 hr/yr


Ownership 3.5$mm @ 8% for 7yr 654.78 436.52

Maintenance & components 400.00 400.00

Fuel @ 85 gal/hr @ 1.00/gal 85.00 85.00

Insurance @ 5% 175.00 116.67

Unscheduled maint. 15,000/ 15.00

25,000 16.67

Support Vehicle

1000 miles/month @ 1.36/mi 1.36

2000 miles/month 1.82

Insurance @ 5,000/yr 5.00 3.33

maintenance 1,000/yr 1.00

2,000/yr 1.33

Office and Airport Parking

Telephone and Fax 1000/mth 12.00 8.00

Office Support 1000/mth 12.00 8.00

Airport 300/yr .30

600/yr .40

Staff Salaries

2 ea Pilots @ 36,000/yr 72.00 48.00

flight pay @ 35/hr 35.00 35.00

pilot overhead 36,000/yr 36.00 24.00

2 ea Mechanic @ 42,000/yr 84.00 56.00

Mechanic ovhd 35,000/yr 35.00 23.33

Driver/Assistant 18,000/yr 18.00 12.00

Per diem & Travel 72,000/yr 72.00 48.00

Total Cost per Productive Hour $1713.44 $1324.07

Note: The breakdown assumes the operator has an ongoing helicopter company providing office facilities, fuel/service truck and other field support.


Waddell, Dale. 1989. Estimating Load Weights with Huber's Cubic Volume Formula: A Field Trial. USDA Forest Service PNW-RN-484. pp 2-3.

Halkett, J.C. 1982. Helicopter Logging, A Review. N.Z. Logging Industry Research Assoc. Inc. PR #17 p.20.

Ashley, B.S. 1991. Simplified Point-Sample Cruising. USDA Forest Service NA-UP-01-91. p E-5.

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