When a drop from an air tanker is needed on a large wildfire, the drop point is usually described to the pilot verbally over the radio, or a lead plane says follow me and then flies over the area identifying the target area either verbally, such as “drop here”, or releasing smoke to visually mark the drop area, or both. The verbal description can be imprecise, and the use of a lead plane requires that the aircraft be committed to that purpose when the air tanker is making the drop.
Matt Richardson, an Avionics Systems Engineer with Canaan Avionics LLC, has designed a system called Multi-Link Drop Computer that would electronically record and then transmit to air tanker pilots detailed information about the desired drop, including navigation data to the drop point, inbound radial, drop point, outbound radial, wind speed, and wind vector. When building line, multiple drop points could be recorded and transmitted to incoming air tankers which would each be assigned a drop point.
Besides the obvious benefit of giving pilots detailed navigation information to the drop point, another advantage we can see is for incidents where the Air Tactical Group Supervisor (ATGS) and the Lead Plane duties are combined and performed by two people in one aircraft, known as an Aerial Supervision Module (ASM). There are times when the Lead Plane needs to be 150 feet above the ground leading air tankers to their targets, but it is also helpful to be thousands of feet up, gathering the big picture for the ATGS. As long as the drop points are not frequently changing due to a rapidly spreading fire, several of them could be recorded and saved, allowing the ASM to go upstairs for a while, directing air traffic, observing the fire, and developing aviation tactics and strategies.
(UPDATE December 11, 2014: we posted three videos that demonstrate the system.)
Below are some excerpts from a white paper Mr. Richardson has developed.
“…Mission Example for LRN via Electronic Display: A Lead Plane identifies a fire ‘hotspot’ by flying over it and marking it with the MLDC. When the pilot presses the ‘MARK’ button, the MLDC instantly records the latitude, longitude, time, wind speed and wind vector at the drop point as received through the GPS data buss. If the pilot holds down the mark button, the MLDC will also record a desired drop length for the duration of the button press and aircraft track while the button is held will become the desired drop vector. The drop point data is given a unique waypoint identifier (FOX12 for example) and stored into a preset. The Lead Plane pilot can go into the MLDC menus and manually augment any of the drop point parameters if desired.
The Lead Plane sends the drop point, FOX12 through a TCP/IP connection by selecting an aerial assent in a list of preprogrammed tail numbers. The drop point data is sent through the onboard AFF Iridium connection to a C-130 still enroute and to a ground based mission coordinator.
The C-130 pilot receives the drop coordinates like an email in the cockpit and loads it into a preset. The C- 130 pilot radios the Lead Plane and aurally confirms that ‘FOX12” was received. The wind data attached to the drop point indicates that there is a heavy crosswind from the west so the pilot uses the MLDC menus to move the drop point 100’ due west.
The C-130 pilot selects the MLDC as the active NAV source using the EFIS controller and a flight plan is shown on the Multi-Function Display (MFD) from his present position to the FOX12 drop point. The drop point flight plan has an intercept vector that matches the drop vector attached to the waypoint. The pilot then selects ‘NAV’ on the flight guidance panel and the autopilot guides the aircraft towards the drop point. While flying to the drop point, the pilot monitors the flight plan and ensures that the predicted path of the aircraft does not impede with other aircraft or terrain. All data is displayed to the pilot on the existing MFD display.
Once the drop point is reached the MLDC sets a discrete which illuminates a ‘DROP’ annunciator to signal the beginning of the drop. The C-130 pilot initiates the drop sequence at that time. The MLDC extinguishes the annunciator once the drop length is reached and the C-130 ends the drop cycle. The MLDC monitors the drop sequence via discrete inputs and records the drop position, vector and length as received through the digital GPS buss.
The C-130 pilot confirms the drop aurally and sends an electronic drop confirmation to either the lead pilot and/or to the mission coordinator using the MLDC…”