
The 747 Supertanker arrived in Bolivia at 1:37 a.m. local time Friday August 23 at Viru Viru International Airport outside the capital city of Santa Cruz de la Sierra and began sorties on fires later in the day.
It appears from the photos above that the method of filling the 19,200-gallon tank may be similar to that used in 2017 when the 747 was working on fires in Chile. In that case there was no robust infrastructure for the distribution of water, so the Santiago Fire Department established a system of portable water tanks filled by water trucks. Fire engines then pumped water from the tanks to the aircraft.

Thank God for 😊❤️944. I was in Oakhurst 3018 CA when it assisted in putting out the Railroad fire.
Following T 944 (N744ST) in Bolivia on this web and Flight Aware, it appears that the operation is moving along smoothly. I was wondering if there is a water enhancement product being added to increase the extinguishment capability of the drops?
Good question. I’m trying to find out myself, without luck so far.
In 2017 when the Supertanker was in Chile it used a water enhancing product called PyroCool. The anecdotal reports at the time was that it was very effective, but the last I heard the product has not been approved by the US Forest Service for use on federal fires in the U.S.
Besides long term retardant, other alternatives that are approved by the USFS are FireIce and BlazeTamer.
I confirmed today with a representative of Global Supertanker that the aircraft has been dropping plain water in Bolivia without any enhancing product.
Neither has the 747 been approved by the Feds. It is rewarding to watch the enthusiasm, excitement and team effort by the Bolivians. As a student of chemicals for wildland fires since 1967 I continue to study the effectiveness of water enhancement products verses untreated water. Several of the water drops (discharged) treated with Pyro Cool from T944 while in Chile (2017) showed a significant change in the “water cloud” as compared to untreated water.