AFDAU-T1 Aerial Firefighting
Data Acquisition Unit
Installation Manual
AMS-IM-1-01 Rev. 7
22 September 2021
6
1.3.5 Drop Start
In order to detect a Drop Start event the AFDAU-T1 must first detect an active Container Door Open discrete input
(refer Section 2.2.3). When the Container Door Open discrete input becomes active the AFDAU-T1 monitors the
container volume for a start of substantive flow of the contents to generate a Drop Start event.
A volume gauge input must be connected to the AFDAU-T1 and properly configured, refer Section 2.2.10
The following additional data will be sent with the Drop Start event message:
Drop Type
The drop type can be one of three attributes:
1. SPLIT
2. FULL
3. NOT APPLICABLE
In some tank and hopper configurations where the drop type can be pre-selected and this information is streamed to
the AFDAU-T1 via a data bus connection, this value will reflect either SPLIT or FULL.
In all other cases this value will be NOT APPLICABLE. Due to the advanced algorithms employed by the AFDAU-T1,
the drop type can be detected in real-time during the drop and will be reported as part of the Drop Stop event
message, see Section 1.3.6
Coverage
Currently transmits a 0. Please contact technical support if further details are required.
Height AGL
Currently transmits a 0. Provisional attribute for future interface to Radalt Systems. Please contact technical support if
further details are required.
Product Type
The product type message can be one of four attributes:
1. WATER
2. GEL
3. FOAM
4. RETARDANT
The drop product type defaults to the product type filled unless an active Additive Pump On (refer Section 2.2.7)
discrete input is detected before the drop occurs. If an Active Pump On is detected, the product type is set to either
FOAM or GEL depending on the state of the Additive Select (refer Section 2.2.6) discrete input. If no Additive Select
input is connected when the Additive Pump On is detected the product type defaults to FOAM.
Drop Pair ID
The ID of the drop pair. This value is unique to each Drop Start and Drop Stop pair to help agencies match each drop
start and stop event. This value is sequential for each drop and resets when the AFDAU-T1 is restarted.
