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We are often asked to compare the hourly cost of manned flights with the equivalent cost of unmanned aircraft systems (UAS).  This is not an easy question to answer because there is not a standardized and accepted protocol for calculating costs per flight hour.  Further, there are numerous ways that costs per flight hour may be calculated because of the varying metrics that may be included in such a calculation. And, most importantly, when upgrading operations, it is often not just the platform that is upgraded but the entire operation is overhauled and the UAS is used differently than its manned predecessor.

          Nonetheless, this is an important question because as more and more UAS are utilized domestically, the price per hour will drop dramatically and serve as a valued metric when supporting future customers.  Further, it is likely that customers may be more interested in leasing services by the hour and not in buying the platforms themselves.  

Why is Comparing Cost per Hour so Hard?

There are a variety of reasons as to why unmanned operations are difficult to compare to manned operations:

• Mission Profile
  • Different Altitude/Distance – Manned systems are generally required to fly at higher altitudes and farther from whatever they are looking at due to regulations or safety factors.
  • Different Sensors – A sensor on a UAS is likely smaller than its manned equivalent, especially because it can fly slower and lower or closer than its manned equivalent.
• Logistics – Taking a UAS from one area to another may only require ground shipping, whereas a manned aircraft often must be flown.
• Maintenance – Needs of a UAS are generally much less than manned aircraft as equipment is generally commercial-off-the-shelf (COTS) and can fly without stringent safety requirements.
• Operator/Pilot – The capabilities and risk to pilots in the air are greater and different than UAS pilots.
• Post Processing – A pilot in the air can visually process information as he/she sees it whereas data from a UAS may need to be post processed. Different communications and sensors compound this issue.
• Weather and Time of Operation – Weather, regulatory, and sensor restrictions may limit either manned or unmanned operations
• Impact on Data – Sound from the aircraft and ability to fly at night and in different weather conditions will change the quality of data recorded. Quantifying this difference can be very difficult.

Some sales tips when comparing manned and unmanned operations:

• Look at Heilmeier’s Catechism (http://en.wikipedia.org/wiki/George_H._Heilmeier): Quantifying answers to these questions with your potential customer and using visuals creates the necessary and compelling case to invest in an alternative method.
• Of Note:

• Understand and relay total cost to customer in as-is condition (see below and here https://www.conklindd.com/CDALibrary/ACCostSummary.aspx for some cost per hour data on manned aircraft and here https://www.conklindd.com/Page.aspx?cid=1115 for additional analysis metrics);
• Quantify the impact of new data on operations;
• Detail total cost of UAS; and
• Quantify any known deficiencies.

Case Study: Bureau of Land Management Use of UAS

          The data presented here are from a presentation at AUVSI’s Unmanned Systems 2013 by Jeff Safran and Lance Brady, Department of the Interior, Bureau of Land Management (BLM) ¹, as part of their close-range photogrammetric mission.  The BLM is the largest land management agency in the U.S. with over 245 million surface acres (700 million subsurface acres) representing 1/8 the land mass of the U.S.

          The BLM Aviation Program is a large manned program focused on safety, dispatch and mission support and is centered at the National Interagency Fire Center in Boise, Idaho.  Overall guidance of the program falls at the DOI – Office of Aviation Services.  The BLM Aviation Plan includes the use of unmanned aircraft (see http://www.blm.gov/style/medialib/blm/nifc/aviation/administration.Par.39484.File.dat/NAP.pdf for details) and the DOI unmanned pilot training and safety inspections programs have been approved by the Federal Aviation Administration (FAA).  An unmanned systems project takes approximately 1 year from initiation to final approval.

          The BLM first became involved in UAS not because of cost factors but because data gaps existed in their remote sensing program.  Landsat 7 ETM+ satellites provide coarse resolution data (30 meter) over BLM lands which is acceptable for regional assessments.  Manned aerial-based (1,500-2,000 feet altitude) imagery yields 1 meter data collected at 3-year intervals.  But for some missions even 1 meter resolution is not sufficient.  UAS imagery at 400 feet yields 5 cm resolution and at 200 feet yields 2.5 cm resolution.  At this resolution, BLM staff can identify invading plants, erosion patterns, animal tracks and collect much more accurate wildlife population surveys.

          BLM has historically tried using sophisticated equipment on manned helicopters to obtain the resolution of interest.  But because of safety concerns, they don’t want a person in an aircraft flying at an altitude of 50-100 feet.  It is noted that the number one cause of death of a wildlife worker is an aviation-related incident (power line strikes—bird strikes—collision with terrain).  UAS can mitigate this danger.

          The first two platforms flown by the BLM was the RQ-11A Raven and the RQ-16 T-Hawk (both provided by the U.S. Army).  The T-Hawk is loud so it is not used for wildlife surveys except to move animals to a designated area.

The Sandhill Crane Population Survey

          The Sandhill Crane Population Survey was a joint project with the United States Geological Survey.  Previous surveys were ocular counts conducted in a Cessna 172 or 206 under daylight conditions above the U.S. Fish and Wildlife Refuge.  A manned Cessna ocular survey costs the BLM about $4,300.  And while the counts could be conducted in just a few flights, the main expense was getting the Cessna to the refuge.    

          At the time of this survey, the BLM also contracted out for a remote sensing contractor to do the same survey using a fixed-wing aircraft.  That contractor’s price for performing the work was $35,000.   

          During the day the birds are dispersed throughout the wildlife refuge so it is difficult to get an accurate count.  However, at night, these birds come back to their roost sites so it is easier to count the birds and with greater accuracy. 

          Ultimately, the UAS crew performed the population survey at night at about 300 feet using thermal imaging from the Raven at a cost of $2,600 for the imagery and about 2 hours to post-process the images.  The Raven is electric powered so the sound did not disturb the birds.  The data provided by the UAS was the most accurate Sandhill Crane count ever conducted. 

          As seen in the chart below, the BLM had a cost-effective reason for using the UAS and achieved the most accurate Sandhill Crane population count conducted to date. 

*Government manned aircraft only included direct costs

The Mesa County Landfill Project

          The Mesa County Landfill Project is collaboration between the BLM, USGS and the Colorado Mesa County Sheriffs’ Department.  The Department has a county-wide Certificate of Authorization (COA) for emergencies.  The County has to write an EPA report on a quarterly basis on the amount of material in their landfill (volumetric compliance inspection).  This is an expensive project as it costs the County about $10,000 for a contractor to fly the project.  Flying their Falcon and Dragonflyer under their COA, the BLM flew the project for about $300. 

The Mesa County Gravel Pit Project

          Similar to the landfill operation, Mesa County also has to perform compliance inspections for volumetrics on their gravel pit.  The county has the same contractor cost here as for the landfill project, about $10,000.  Again flying under the County’s COA, the BLM was able to provide photogrammetric expertise to the County for about $120. 

          The BLM is continuing to test and evaluate UAS systems but continue to face bureaucratic challenges. Since unmanned systems are part of the manned aircraft program, BLM staff have to provide the same justification to buy a $5,000 UAS as they do to buy a Beechcraft KingAir at >100x cost. 

          On the brighter side, the DOI has worked out an agreement with the FAA which will allow the BLM to fly over DOI lands without a COA in class G airspace: <1,200 feet at >10 miles from an airport and <400 feet between 5-10 miles from an airport.  This agreement was to be signed just before the government shutdown.

          While there has been much anecdotal evidence that UAS are more cost effective than manned flights, this is among the first direct evidence that this is, in fact, the case.  If any of our members have similar data comparing manned flights to UAS performing the same mission, we would appreciate hearing from you.   

Survey of Various Manned & Unmanned Aircraft Systems Unit and Per Hour Flight Cost

Although unmanned vs. manned per flight hour costs are not standardized and therefore cannot be utilized as a direct comparison, this section presents unit and per hour flight costs for manned and unmanned aircraft systems from various sources.  Operating price per hour and cost of maintenance are two of the many metrics that can be utilized to better understand where manned systems should be used and where unmanned systems can be more effective and efficient.  The following unit and flight hour operational costs were found in a quick review of the literature and are provided only for illustration purposes and not for direct comparison.

  The Government Accountability Office (GAO), in a report on border security, (http://www.gao.gov/products/GAO-12-657T) stated that the Department of Defense (DOD) reported in fiscal year 2011 that the Predator UAS cost $859/flight hour and the Reaper $1,456/flight hour.  GAO further reported that DOD used maintenance costs, asset utilization costs, and military personnel costs in their calculations.  It is noted that many other factors may impact actual operating cost and there is not a standardized method for performing this calculation.  For example, direct operating costs may also include such items as maintenance, fuel and lubricants. However, these costs are dependent upon hours flown.  To this may be added hanger, maintenance and personnel costs (direct and indirect) including operators, mechanics and administrators of the program.  Some cost estimates may include depreciation and the present value of the costs per contract divided by the average contract length in order to estimate total operational costs.  Therefore, it is not surprising that one can find highly variable cost estimates for the same UAS (see Hiesterman, http://www.washingtoninstitute.net/ftpFiles/StudentFinalProjectReports/TFM24/WardHiesterman.pdf  for a detailed cost effectiveness analysis of helicopter contracting practices).     

Although not directly comparable, the GAO also reported that a manned Blackhawk helicopter cost $5,897/flight hour and a C-12 $1,370/flight hour.  These aircraft are similar to those used for border security.  To develop these per hour estimates, the DoD used maintenance, asset utilization, and military personnel costs. 

          Aviation International News (http://www.ainonline.com/aviation-news/ain-defense-perspective/2012-04-20/k-max-proves-unmanned-heli-lift-afghanistan) reports the logistics transport K-Max unmanned helicopters being used in Afghanistan by United States (U.S.) Marines have a cost of maintenance less than $1,200 per hour and 0.8 maintenance man-hours per flight hour.  

          Manned helicopters used by first responders (law enforcement, firefighters, emergency medical services, etc.) and ready for service can run from $1.5 - $4 million and average $1,000/flight hour to operate (http://www.wired.com/autopia/2011/09/tomball-police-autogyro). 

          The Bell Jet Ranger, typically used for traffic or news reporting, costs $700K - $1.2 million and $649/flight hour to operate (http://sanford.duke.edu/research/students/spring2004-01.pdf). 

          The Robinson R-44 Raven II, a two person helicopter, costs $434,000 and operates at $206/flight hour (manufacturer’s estimate) (http://www.robinsonheli.com/price_lists_eocs/r44_2_eoc.pdf). 

          The Sikorsky S-76, used by EMS and the Port Authority of New York and New Jersey (two S-76’s) for security, has cost the city $4 million/year at a cost of $15.5K/flight hour (http://blogs.law.harvard.edu/philg/2010/07/17/government-versus-private-industry-helicopter-operating-costs).

          According to the US Air Force a Predator B UAS has a unit cost of about $4.026 million (http://www.saffm.hq.af.mil/shared/media/document/AFD-100128-072.pdf) and an operating cost of approximately $3,234/flight hour.  A modified Predator B was utilized by NASA to assist firefighters in pinpointing hot spots and obtaining ground temperatures during the 2007 California Zaca and Mount Palomar Observatory (vicinity) fires (http://machinedesign.com/print/73728 and (http://machinedesign.com/article/newest-forest-firefighter-predator-uav-1121). 

          The UAS Bell Eagle Eye has a unit cost of about $8.3 million and an operating cost estimated at $1k/flight hour.  The Coast Guard’s HH-65 Dolphin manned helicopter has a unit cost of $9 million and an operating cost estimated at $6,253/flight hour (http://www.navyleague.org/sea_power/aug06-33.php).

          It is noted that a single Raven has a price estimate of from $35K (http://www.globalsecurity.org/intell/systems/raven.htm) to $250K - $439K for the entire system (http://www.robinsonheli.com/price_lists_eocs/r44_2_eoc.pdf).  This demonstrates the difficulty in assessing the true operational cost per flight hour of both manned and unmanned systems.  Such estimates should be from primary reference sources and reflect all assumptions and factors utilized in the calculations. 

          The below chart summarizes the platform, primary use, unit cost and cost per flight hour for several manned and unmanned aircraft systems but does not include the metrics utilized for estimating these costs.  It should be remembered that these costs are not directly comparable and should only be used as rough estimates to start a comparison.

¹Safran, Jeff and Brady, Lance.  Bureau of Land Management: Use of Unmanned Aerial Systems and Cose-Range Photogrammetry Techniques.  AUVSI’s Unmanned Systems 2013.  August 14, 2013, Washington, D.C.

(Update: 10/29) Found some more data from the US Air Force Comptroller (via Time):