One of the recommendations from the first report on the Yarnell Hill Fire that killed 19 members of the Granite Mountain Hotshots on June 30, 2013, was:
The Team recommends that the State of Arizona request the WFLC/NWCG to develop a brief technical tip for fire supervisors/agency administrators on the effective use of
[Very Large Air Tankers] VLATs. These are new, emerging fire suppression tools that the ground-based fire supervisors may be utilizing regularly in the future.
Before that report was made public, the state of Arizona released information on July 16, 2013 about the resources deployed on the Yarnell Hill Fire, saying in part, that a DC-10 Very Large Air Tanker (VLAT) was in Albuquerque and available on June 29 (the day before the fatalities), but was not ordered then due to Air Attack’s concern about its effectiveness in steep terrain and inability to deliver retardant before cut-off time. Dispatch offered the VLAT, a DC-10, to air attack at 5:43 p.m. Few people with knowledge of the terrain on the fire and the capabilities of the DC-10 VLAT would conclude that the terrain was too steep for the DC-10. In fact the next day both DC-10s were used on the fire, making 8 sorties and dropping over 88,000 gallons.
Albuquerque is 308 nautical miles away from the fire, and sunset that day was at 7:47 p.m. The DC-10 cruises at around 370 knots (TAS), so it seems likely that the VLAT could have easily made one drop, 11,600 gallons, before cutoff time of 8:17 p.m., 30 minutes after sunset. The Yarnell fire was not doing too much that day, so a VLAT load of retardant might have made a difference. At 5:30 p.m., before a slopover occurred, there were 13 firefighters working on the fire and only six acres had burned. The fire was not staffed that night, so taking advantage of the drop by ground personnel may have been problematic.
In response to the suggestion in the report about “a brief technical tip” for the use of VLATs, the U.S. Forest Service and the National Wildfire Coordinating Group distributed the below information to the Geographic Area Coordinating Groups on March 27, 2014. One interesting fact that the USFS developed — for a 100 nm dispatch it costs more than twice as much per gallon (the “user cost”) for four P2V air tankers to deliver 8,320 gallons of retardant than it does for a DC-10 to deliver 11,600 gallons.
“US Forest Service
Fire & Aviation Management
DC-10 Briefing Paper
Updated May 1, 2014
Topic: Follow up – DC-10 Very Large Airtanker (VLAT) Operational Considerations
Issue: The DC-10 has unique operational considerations including low level supervision, terrain, facilities, and cost.
Background: 10 Tanker Air Carrier was awarded a line item for a DC-10 on the Next Generation Large Airtanker Exclusive Use contract and a line item on the Very Large Airtanker (VLAT) Call When Needed contract. These aircraft remain a VLAT in category and require special considerations for use.
Low Level Supervision: Aerial supervision is required for this aircraft while dispensing.
- The 10 Tanker flight crews will not be issued an initial attack (IA) approval card, so a Leadplane or Aerial Supervision Module must be on scene to direct the resource to the intended dispensing locations.
- The cruising speed of the DC-10 is around 370 knots (TAS) which is greater than Large Airtankers (LATs) and leadplanes. Users/ dispatchers need to insure that a LP/ASM will arrive in time to provide aerial supervision.
- Trainee Leadplane Pilots (LP) under the supervision of an onboard Leadplane Pilot Instructors (LPI) may conduct VLAT operations. All LPIs are now qualified for VLAT operations and will supervise the trainee during these missions.
Terrain: VLATs are less maneuverable than LATs and should be used in less challenging terrain that affords better maneuverability for dispensing.
- The DC-10 is relatively agile for its size; however the momentum is greater and requires planning by the supervising aircraft to provide a stabilized path for delivery.
- The VLATs minimum drop height is 200 feet above the top of the vegetation with a target height of 250 feet.
Facilities: The DC-10 weighs between 340,000 and 400,000 lbs. in contract configuration. It has a Dual Tandem wheel configuration.
- Tanker Base and parking ramps must have a weight bearing capacity sufficient to support the DC-10. Local bases need to insure both the airport and agency engineering have information indicating ramp capacity. Letters documentation and drawings of the ramp structure must be on file at the airtanker base.
- Congestion at a base may preclude operations due to conflicts with other aircraft types.
- Air stairs are needed for the crew to enter/exit the aircraft. 10 Tanker is responsible for the payment of the stairs and airtanker personnel are not to operate the equipment.
- Loading the aircraft will take anywhere from 12-15 minutes with a three pump/hose configuration or 25 minutes with a one pump/hose setup.
- Simultaneous Loading and Fueling and/or Hot Retardant Loading (HRL) is acceptable only after approval of the corresponding Regional Aviation Officer and the local line officer and being added to the base operations plan. The local airtanker base manager (ATBM) is delegated the decision authority once this is in the base plan.
- Facilities that accept the DC-10 will need to provide offload capacity of at least 10,000 gallons.
Cost: The FS funds the availability of $27,285 per day. The rate is on par with Next Gen LATs awarded under this contract.
- The dry flight rate is $12,750/hour when the aircraft is fully loaded with retardant to 11,600 gallons. When the aircraft is carrying 5500 gallons or less the rate drops to $4598/hour. After 150 hours of use, a further price adjustment occurs.
- The DC-10 has an hourly fuel consumption of 2275 gallons when carrying 5500 gallons or less and 2550 gallons per hour when fully loaded. The Forest Service utilizes the Aviation Into-plane Reimbursement (AIR) cards sponsored by the Defense Logistics Agency (DLA) for purchasing fuel. This provides the government a cost savings of about $1.50 per gallon from the retail rate.
Contact: Scott Fisher, WO-FAM National Airtanker Program Manager (208) 387-5968.”