The 747 Supertanker is an aerial firefighting aircraft based on a Boeing 747 widebody aircraft. Initially developed by Evergreen International Aviation, the first Supertanker was based on a 747-200 (N470EV, tanker/tail number 947), and never entered service.
First flight was May 2, 1974. Delivery date was June 10, 1974. Other serials – N470EV with Evergreen Int’l Als, & Southern Air Transport, and also N749WA with World Airways, VIASA – Venezolana Internacional de Aviacion, Braniff Int’l Airways, American Als, Lufthansa, Korean Air Lines, & Evergreen Int’l Als. Wears FN 749 with Flying Tigers. Converted to Supertanker 947 water-bomber in 2004. Stored at MZJ (Marana) on February 25, 2012 as N470EV, & was broken-up after February 2012 at MZJ
Development started after the 2002 fire season, which saw the fatal crashes of two air tankers in the USA. The accidents, involving a Lockheed C-130A Hercules and a Consolidated PB4Y-2, prompted the U.S. Department of Interior to issue an official Request for Information on next-generation airtankers.
Evergreen proposed to convert up to four of its Boeing 747-200 Freighters into massive ‘Supertankers’. The first converted Boeing 747 (N470EV) made its maiden flight on February 19, 2004. The current Supertanker is N479EV, a 747-100.
By June 2006, Evergreen had spent $40 million on the project and was hopeful of both FAA certification, and an evaluation contract from the US Forest Service. In October 2006 the FAA issued Evergreen a supplementary type certificate for the installation and removal of internal tanks, associated systems and support structure for the aerial dispersant of liquids.
An issue that impacted usage by the Forest Service was the USFS requirement for using fire retardant rather than water. When Evergreen attempted to convert the system from water dispensing to retardant, they encountered objections from the FAA. The FAA’s issue related to the much greater density of fire retardant and the corresponding increased stress on the airframe thus delaying the FAA certification. The FAA determined that the Supertanker’s service life would be diminished and also raised concerns about the dangers of additional stress on the airframe during firefighting operations and heavy weight maneuvering.
Oh yeah, let us understand the life of this aircraft!
All images are sourced from Google Images, Airliners.net, jetphotos.com, Wikimedia Commons, flickr.com, planespotters.net, airplane-pictures.net
Music: Katie Sky – Monsters
Note: This modified Boeing 747-273C freighter, named Supertanker 947 and registered as N470EV, actually the first modified Supertanker.