Aerial Dispersant Operations in the Deepwater Horizon Spill Response - A Framework for Safely Mounting a Large Scale Complex Dispersant Operation Open Access

When an oil spill occurs fifty miles offshore, spill response professionals turn to aerial application of dispersants as the only immediate and effective response. An oil slick from a large spill in open water can spread out over 10 square miles overnight, as was the case in the Deepwater Horizon spill. Airborne Support, Inc (ASI) is an organization dedicated to aerial dispersant application located in Houma Louisiana, with three spray aircraft and two spotter/surveillance aircraft. On April 22 ASI began the first spray operation having been activated immediately by BP. Another organization with smaller spray and spotter/surveillance aircraft, Dynamic Aviation, had a base at Stennis Airport, Kiln Mississippi, through an arrangement with Marine Spill Response Corp. (MSRC) and was also activated. Meanwhile, the MSRC C-130 spray aircraft, and the Clean Caribbean & Americas (CCA) ADDS Pack and C-130, the largest aircraft systems, were activated from distant bases, all to begin intensive spray operations April 25 as the enormity of the spill was realized. Within one week, special spray operation C-130's from the United States Air Force Reserve would join in. Eventually, ADDS from Alyeska Servs (Alaska), and Oil Spill Response (OSR, England) would be brought to the operation, as well as smaller agriculture spray aircraft for nearshore use.

Each of these components have their own standardized procedures for flight operations and dispersant spraying. Each has its own training and safety programs. The pilots are certified to operate in visual and instrument conditions, within and outside US air traffic control space.

None had ever worked together as integral components of a joint, twenty aircraft operation, that functioned 14 hours per day, seven days a week, over an area of 18,000 square miles, in congested airspace, within the most complex oil spill response of this era. There were no standard operating procedures for this size of operation, where safety is paramount. The evolution of those procedures began out of necessity.

In the early hours of the response, the RP/QI selected the head the Aerial Dispersant Group. From the first moment that he was enroute to Houma, Louisiana and for the next week, the Group Supervisor was building the organization and assembling a team of aviation and dispersant experts as well as spray and spotter aircraft and crews. Many tasks had to be satisfied in order for the operation to grow from the single aircraft operation that performed the first spray on April 22^nd into a structured mission capable team. The result:

Operating Base Houma, Louisiana

Airborne Support Inc. 1 BT-67, 2 DC-3, 1 Piper Aztec, 1 Turbo Commander.

Lane Aviation 2 AT-802

Dynamic Aviation 1 Beechcraft King Air

ASI has operated since 1991 providing aerial dispersant application services in the Gulf of Mexico. As such it was uniquely positioned to be the first on scene and the last to detach. Its pilots, and crews have worked together to provide both spraying, surveillance and spotting in the Gulf, for both exercises and actual spills.

NOTE: Spotting by “spotter” aircraft is the term that describes the directions given to the spray pilots to adjust their flight paths over the optimum portions of the oil slick, and the command “spray on” and “spray off”. It is a rare and unique form of aviation that only extensive experience can provide. Most of the spotter pilots have experience from fighting forest fires, directing fire retardant and water drops on fires. The spotter/sprayers fly different patterns for fires than for oil spills. A typical aerial dispersant mission requires one spotter aircraft and one or two spray aircraft.

Lane Aviation operates agricultural spray aircraft across the Gulf and single engine tankers as fire bombers on forest fires around the country. Although most of their pilots are highly experienced in fighting forest fires from the air, a few of their pilots had previously practiced oil spill dispersant application using water only. This was the first time that an AT-802 was used to spray dispersant on an oil spill flying over water in North America even though AT-802's have been used in other countries around the world to apply dispersant to oil spills for more than 15 years.

Operating Base Stennis, Mississippi

MSRC/International Air Response (IAR) 1 C-130 Hercules

Clean Caribbean & Americas (CCA)/Lynden Air Cargo 1 L-382 Hercules

United States Air Force (USAF) 3 C-130 Hercules

Dynamic Aviation 7 Beechcraft King Air (2 configured for spraying)

MSRC, IAR, and Dynamic Aviation had recently formed an aerial dispersant capability to meet impending US requirements for their oil industry clients. Ironically, they were preparing for an exercise the very week of their mobilization for the DWH spill. Their pilots and crews had worked together over the last five years and had used the Stennis Airport as their home base of operation.

CCA and Lynden Air Cargo train and operate together. Annual training in the ADDS operation, including spotter training was recent.

The USAF C-130's are from the 910^th Airlift Wing, Youngstown Air Reserve Station, Ohio. They are multi-mission and have many spraying missions. Although they had exercised for an oil spill twice previously in the last 15 years with other operators, they had never actually sprayed dispersants on oil slicks. (NOTE: The AF was replaced in June by two ADDS/L-382 Hercules; one from Oil Spill Response, England, and another from Alyeska SERVS, Alaska).

None of these units had worked in a joint oil spill response operation of this magnitude and intensity. All had worked and trained as individual units under company management. This was to change when they all came under the direction of the Aerial Dispersant Group, Operations Section, Houma Incident Command for the DWH response.

Aerial Dispersant Group staff structure is explained in Table 1. Each position was filled by experts in their field, there were no rookies. The staff worked one shift only, starting as early as 0530 and extending to 1930 and often until 2130–2200.

All positions required contact reliefs to fill in for two to five days when the incumbents were ordered to take time off after every two to three weeks on the job. These reliefs had to be appropriately skilled, with overlapping on-the-job turnover.

Each operating base, and each operator had their own standard operating and safety procedures built from experience and Federal Air Regulations (FAR's). The key to the initial success and safety stems from this expertise. As the Aerial Dispersant Group grew, and the oil spill response itself grew, the need for command and control grew rapidly. Communication was the key. Within the Group staff, each base had a coordinator/liaison who passed information and tasking, received reports from the operators, and maintained two-way communication throughout the day. Standardization of procedures grew as the event grew. Each evening a teleconference joined the Group staff with the base operators to review events, procedures, and the next day's missions. We found the Houma Incident Command Chaplain as the willing lender of his office and telephone for the quiet privacy that we required.

Optimum flying weather consists of clear skies and unlimited visibility. Unfortunately, this is not always the case. The spill response occurred during transitional weather from winter to summer, from cold front weather, high pressure-blue sky, through mixed clouds, morning fog, and summer thunderstorms. It was important to standardize weather minimums for Aerial Dispersant Group spray operations. The weather criteria in Table 2 resulted from inputs from all of the operators, Air Operations, and staff and are more stringent than basic VFR. The Group and Air Ops did not desire “scud running” (flying beneath a low cloud layer to maintain visual conditions) in the congested airspace. Entry and exit points for IFR to VFR were established by the operating bases and made part of the overall airspace plan. There are numerous sources of National Weather Service aviation weather information, available even on I-phone applications that we used. Offshore buoys and platforms could relate wind and sea information along with temperatures and dew points. The extremely important information that was most difficult to obtain was the offshore cloud ceilings. The USCG cutters in the area did not have the equipment to measure ceilings. Direct telephone calls to persons on the Seacor Lee command ship provided only general cloud information. The only satisfactory report of cloud bases offshore could be made by aircraft in the air, and that meant that our first spotter launch would serve as our weather reconnaissance. Future large scale operations should include specially designed laser systems called ceilometers on board command vessels to provide this information.

While operating under the pre-approval procedures, the flight schedule required spotters to be airborne at daylight, sprayers to follow 30 minutes later based on spotters finding oil. Spray flights continued until 30 minutes prior to sunset when sun angles made oil colors and texture more difficult to discern as dispersable. Each base improved turnaround times with novel approaches to the setup and connections of storage tanks, pumps, and hoses. The Air Force with its own ground support equipment, could reload dispersants and get its C-130 back in the air after only 15 minutes on the ground if it did not need fuel for the next flight. On May 10^th for example, both of the AF C-130 aircraft each flew five sorties, the other C-130's with the larger payloads each flew four.

With an abundance of oil on the surface during the early days of the response, finding suitable oil to disperse was never an issue. There was no In-Situ Burning, and there were few oil spill response vessels concentrated near the source. The area was simply divided with a north/south line for the two operating bases. A six mile buffer zone was used to avoid conflicts. (See Illustration 1)

In addition to providing a daily flight schedule as part of the Daily Aerial Dispersant Application Plan or DADAP, basic instructions were issued. For example, the instructions for May 4^th were:

1. No dispersant spraying within 3 nm (nautical mile) radius of source.

2. Maintain buffer of 3 nm each side of division boundary.

3. Designate, brief, and use entry and exit points when applicable.

4. No dispersant spraying within the greater of 3 nm offshore or depths less than 10 meters as depicted on nautical charts.

5. Target black and brown oil as close to 3 nm “No Spray” area around the source as this is the freshest and most dispersible oil.

6. Target reddish brown oil further away from the source.

7. Report takeoff and land times to assigned coordinators as they occur. Report areas sprayed.

8. At the direction of Aerial Dispersant Group Operations a double or triple test pass may be done to determine appropriate dosage. ASI assigned to conduct this spray test on 4 May and to coordinate with SMART for monitoring and photography of results.

9. Coordination Frequency 123.45 MHz (Spotter, SMART, Surveillance)

All aircraft were also instructed to use a dispersant application rate of five gallons per acre (5 gal/acre). Only Corexit 9527 and 9500 were used on the Mississippi Canyon 252 crude oil.

Communications on 123.45 MHz was initially adopted because that is the single coordinating frequency for helicopters supporting the offshore oil industry in the Gulf. This frequency soon became saturated. When airspace management was enhanced other frequencies were available. The spotter/sprayer teams used their own “company” frequencies for close coordination. The spotter pilots maintained a listening watch on guard and the common area frequency while the sprayer pilots only listen to the company frequency for all information due to the rigors of flight at such low altitudes (50 to 75 feet).

Targeting became dramatically refined when:

• The number of spray aircraft increased to nine.

• In-situ burning became a primary response tool and encompassed a very large area and safety zone of up to 400 square miles (20 × 20 mile box).

• The source control zone safety area was increased to a five nautical mile (nm) radius.

• Skimming vessel fleets occupied large areas.

• Leaking oil was being both recovered and dispersed at the source, allowing less oil to reach the surface.

• Beyond 50 nautical miles, the oil was usually heavily weathered and mixed with Sargasso, rendering it not amenable to dispersants.

Working with the airspace manager from Tyndall Air Force Base and the FAA representative, a new grid system was created. Each grid box was 30 degrees of longitude and 30 degrees of latitude, and so approximately 30 by 30 nautical miles, easy to depict on charts, and easy to compute in pilots and planners minds.

Based on reports of oil throughout the day, the operating bases were assigned grid zones. In Illustration 2, we used color coding for the assignments. The burn box is clearly visible and large, the black slicks represented actual sightings of oil. By this date, the AT-802 Air Tractors were fully operational and authorized to operate out to 15 nm offshore.

With integral spotter pilots/aircraft that can also perform surveillance, and due to the uniqueness of the constantly releasing oil spill, the Aerial Dispersant Group performed all of its own targeting including prioritizing. We did occasionally receive reports of slicks from the Planning Section and other Operations units. We investigated these slicks with our own aircraft and determined suitability for dispersant application. All pilots received aerial observation training from NOAA during a day of no flying due to weather to enhance standardization and ensure quality control.

Because the Air Tractors (ATs) are single engine, single pilot, there was a need to ensure the highest degree of safety before including these highly versatile aircraft into the spray group. A step-by-step program of training flights involving a two-seat trainer version of the AT led from the initial approval to an offshore limit of 15 miles eventually to 40 miles for the single pilot aircraft. One spotter aircraft always worked with a single AT. Written procedures were adopted and proved during the successful introduction and integration into the Aerial Dispersant Group. The AT's proved to be an excellent aircraft to spray near shore, especially due to their maneuverability and rapid turnaround.

The Aerial Dispersant Group rejected use of the Evergreen company Boeing 747. Although it complied with the ASTM standard for dispersant application, and was FAA Part 137 certified for spray operations, the aircraft was not versatile for the type of spray that was being conducted in constricted airspace. We questioned its ability to minimize overspray and to apply small quantities to small slicks. The aircraft turn radius is excessive and undermines its ability to perform agile movements under spotter direction. This and the fact that we always had 4 C-130's for large quantity application made the 747 unnecessary.

Due to the high volume of traffic in the area, both spill related and routine oil industry support, it was a high priority of the Incident Command and its Operations Section to make viable, safe procedures for best utilization of the airspace. An airspace coordinator from Tyndall Air Force Base was present early and soon joined by an FAA representative. Together they created the Temporary Flight Restriction, or TFR, from the surface to 3,000 feet to keep non involved air traffic out of the area. The TFR grew in lateral dimensions as the oil spill progressed to the Louisiana shores. Senior officials called on other national assets such as the Coast Guard, Air Force, Navy and others to provide real time air space management. A Coast Guard cutter was given duties to flight-follow aircraft involved in spill response, but it could not work due to radio reception ranges. A Navy carrier or Aegis cruiser was considered and rejected along with USAF AWACS. Finally the US Customs and Border Patrol provided a 12 hour on-station P3 aircraft (OMAHA 99) for flight following and traffic advisories. The communication frequencies were then split into two regions. Spotter and sprayer aircraft were required to check in and out with OMAHA 99 on their assigned IFF code and report their mission. This had better usefulness but still could not provide full service due to high traffic volumes. Had there been an emergency, the airborne P3 could have provided vital services. Thankfully there were none.

The most useful of all the safe airspace actions was the dedication of the airspace from the surface to 1,500 feet for spray/spotter operations. (See Illustration 3.) This still included other surveillance aircraft at times, and spotter aircraft for in-situ burning teams and vessels skimming teams. But overall, by ordering the transiting helicopter aircraft to fly above 1,500 feet, the sky was safer. Our aircraft transited above the TFR (above 3,000 feet) whenever possible in order to minimize risks.

The assignment of zones to the respective airbases was also made with safe transit in mind. The goal was to never expose our own aircraft to the chance of a midair collision with each other. Each operating base practiced radio communications between arriving and departing aircraft.

The complexity is illustrated in Illustration 4, showing 128 sorties within the context of the spill response. Aviation Coordination Command airspace managers assumed complete control July 9, 2010, at the 601st Air & Space Operations Center at Tyndall AFB, Fla. Scheduling was ultimately taken over by the Tyndall Air Force Base Airspace Management unit. That there were no midair collisions, was a testament to the great efforts of all the pilots and operators.

The pilot's report of oil located and oil sprayed took several forms of transmission to the Aerial Dispersant Group:

1. Verbal over telephone to the base coordinator when immediate information was required.

2. E-mail of a written and picture format report. (See Illustration 5)

3. Electronically via the onboard aircraft tracking system.

All of these methods were important. The telephone and e-mail reports were vital for determining the disposition of dispersable oil during surveillance flights that preceded a request for spray authorization after May 26 when a new process was in effect. (See Joeckel et al) The electronic report was the most valuable for long term record keeping and for depicting the full day's events on one GIS map display. The ADDS systems did not have built in systems so personnel from CCA together with a technician from Heynsight developed a protocol for using a portable Garmin GPS to report the time/track of the spray runs back to the Aerial Dispersant Group for plotting and archiving.

The post flight reconstruction of spray runs was an important record of performance. Because we received complaints from persons on platforms and vessels alleging that dispersants were sprayed on them, we were able to reconstruct each event and prove in every case that these were false. The electronic reporting system became a mission essential item: no tracker, no spray.

Another form of reporting was real-time tracking. Several aircraft had the built-in Sky Connect system that used an internet based GIS to show aircraft location and data. Those that did not have this were issued a Blue Force Tracker, courtesy of the US Air Force. This small, fist size, battery operated device depicted the aircraft on a Google Earth internet screen through a system known as Automated Flight Following (AFF). The AF also provided layers for presentation that included: FAA Temporary Flight Restriction areas, the National Buoy Data System, real-time weather radar, and real-time vessel positions derived from AIS. The data was displayed on a 50-inch plasma TV in the Aerial Dispersant Group corner of the ICP, and was very useful to the coordinators and to the IC officials to get a constant picture of events.

Although no two days were ever the same, a routine gradually evolved:

• 0530

  • Weather reports

  • Automated Flight Following (AFF) display initiated

  • Flight Schedule open

  • Airspace assigned

• 0600

  • Dispersant Ops Group team meeting

• 0630

  • Air Ops meeting

  • Record oil locations and sizes from Spotter Aircraft; Provide input to FOSC for daily dispersant approval.

• Throughout day:

  • Coordinate with operating bases.

  • Coordinate targeting.

  • Coordinate with SMART team.

  • Record take off and land times, compile spray reports.

  • Coordinate with Air ops, aircraft positions, status.

  • Plan next day’s events.

  • Review standard operating procedures.

  • Trouble shoot problems.

• 1830

  • Initiate conference call with operating bases.

  • E-mail to entire group the next day’s airspace divisions, operational notes, and flight schedule.

  • Provide draft FOSC dispersant request to Group Chief.

• Issues:

  • Safety

  • Weather minimums for spray ops

  • Weather updates

  • Aircraft and airspace deconfliction

  • Air to Air communications

  • Air to Vessel communications

  • Air Crew rest

  • ADIZ penetration: assigned squawks

  • Safe separation from vessels, platforms, marine mammals, spill source zones, in situ burn zones, etc.

  • Oil location updates and priority targeting

  • Dispersant stockpiles

  • Dispersant transfers

A requirement to use dispersants is that SMART (Special Monitoring of Applied Response Technologies) is available and used to confirm that dispersants are working. The USCG Strike Teams initially provided SMART and were augmented by Oil Spill Response, Ltd. later in the response. A separate paper addresses the coordination issues and the data provided by SMART. See Levine et al. For this paper it should be noted that this is an important element and a key to a successful dispersant operation. Great efforts were made to schedule events closely, position Tier 2 SMART vessels in areas of forecast spray operations, and provide joint briefings and periodic training reviews with spotter, sprayer, and SMART personnel.

It is obvious to any observer that the aircraft operations, dispersant transfers, and large number of moving people and machines combined into one operation could be hazardous. There are indeed many hazards that had to be addressed. The aircraft operators were all FAA certified and visited repeatedly by OSHA and other safety agencies. All personnel were constantly looking for hazards and safety issues in every plan that we proposed and every system that we operated. Pilot duty cycles were addressed by company policy and met FAA requirements of no more than 10 flight hours in a 14 hour duty period (See Reference FAR 91). Staff fatigue was addressed by the Incident Command that ordered all to take days off after two to three weeks. Pre-flight briefings included safety items, flight restrictions, weather, and emergency procedures. Daily conference calls addressed every issue that could present a hazard to the operation and to individuals. Each operating base had a leader who was charged with safety. These persons had the authority to cease operations if they thought things were unsafe, and they did when weather or other circumstances occurred. The Group operations staff constantly raised issues for the operators to address in the form of “what if?” such as maximum surveillance range, feasibilities of additional aircraft, last plane on deck time, first launch times. Each incident shown in Table 3 was fully investigated, with remedial actions carried out.

Except for the false reports, none of the incidents were repeated from the same causes. The four visits to a physician were minor and next day returned to duty. Spray flights ceased in July, however the operation was maintained in standby until August 7^th. The fact that the Aerial Dispersant Group flew 412 sorties, spraying nearly one million gallons of dispersants (Table 4) shows that this type of operation can be safely accomplished on a grand scale.

• Annual or more frequent training and realistic management exercises are paramount in ensuring experienced, knowledgably responders are available to manage a spray operation and to build the command/control structure as soon as possible for an actual response.

• Conduct spray training and spray exercises for crew and aircraft readiness. Training between different dispersant operators on a joint exercise would prove particularly useful to maintain the capability that was created during this event.

• In the early days of a spill response, and as soon as possible, the Aerial Dispersant Group must set procedures for scheduling, airspace management, communications, targeting, reporting, SMART integration, safety reviews. This is simple for a single spray aircraft operation; the complexity increases with the number of aircraft systems that are required for the size of the spill.

• Maintain and build new experienced personnel. Aerial observation training is a key element for surveillance and spotter functions. Despite technology, there will always be reliance on Mark 1 Eyeball (human observation) for locating dispersible oil and the effectiveness of the application.

• Industry should develop and use common tracking and reporting hardware/software.

• Air-to-surface and air-to-staging base communications are always necessary during spill responses and especially for SMART coordination. Although handheld marine radios were provided, they detract from overall flight effectiveness and safety. There is a need for a marine band radio to be built into spotter aircraft.

• Dual engine, dual piloted fixed wing aircraft are necessary to perform spotter missions for fixed wing spray aircraft. Most helicopters do not have the transit speed or endurance for offshore spraying as was the case in DWH.

• The lessons learned from this response for mounting a large scale aerial dispersant operation could be applied throughout the world for a response to a continuous release offshore.

ADDS

aerial dispersant delivery system

ADIZ

air defense identification zone

AF

Air Force

AFB

air force base

AFF

automated flight following

AGL

above ground level

AIS

automatic identification system

ASI

Airborne Support, Inc.

AT

air tractor

CCA

Clean Caribbean & Americas

DADAP

daily dispersant application plan

DHASS

Deepwater Horizon aviation support schedule

FAA

Federal Aviation Administration

FAR

federal air regulations

GIS

geographic information system

IAR

International Air Response

IC

incident command

ICP

incident command post

IFF

identification friend or foe

IFR

instrument flight rules

MSRC

Marine Spill Response Corporation

OSR

Oil Spill Response

RP/QI

responsible party/qualified individual

SFC

surface

SMART

special monitoring of applied response technologies

TFR

temporary flight restriction

USAF-R

United States Air Force Reserve

USCG

United States Coast Guard

VFR

visual flight rules