For those interested....
One failure that occurred that day that had some major ramifications was a failure in one of the firefighting vehicles, the P-18 water tender (pictured below). The P-18 is a 2000 gallon ARFF water tender which is primarily used as a resupply truck for ARFF crash trucks, as well as having a secondary firefighting capability of its own with water only, as the P-18 doesn't possess a foam capability. Water tenders are exceptionally important vehicles for ARFF use since ARFF crash trucks pump at about 500 gpm, and carry anywhere from 1000 gals to 3000 gals of water. The two ARFF trucks of the 185th, a P-4 crash truck and a P-19 crash truck, contained 1500 gals and 1000 gals of water, respectively; so each only had about 2 minutes of fire suppression capability with the water at full discharge rate, and about another 45 seconds each of Halon 1211 (500 lbs) for the P-19 and 45 seconds or so of Purple-K powder dry chemical for the P-4. After that, the ARFF trucks are dependant on the P-18 to resupply them with water so they can get back to work. The other vehicles available to the 185th CFR dept that day were a P-13 ramp chemical truck with 450 lbs of Purple-K powder dry chemical, and 500 lbs of Halon 1211; and a P-10 rescue truck with 25 lbs of Purple-K dry chemical.
5 months prior to the accident of UA232, there had been a failure of one of the P-18 vehicles during a training operation at Tyndall AFB, FL. It was found that the tank-to-pump water line, a soft-hose, had become blocked by a PVC stiffener that had rotated 90 degrees within the line and in-essence, blocked the water line. The Tyndall AFB fire department determined it to be a failure of that particular vehicle, and they instituted a quick fix for it. However, unknown at the time, there was actually a design deficiency with that tank-to-pump hose and the internal stiffener which was of a small diameter than the hose itself. This problem didn't manifest itself when the truck was pumping at lower pressures, but only at its full 500gpm rate, which wasn't often done nor required, in order to not unduly stress the pump on the truck for just training operations.
Following the crash of 232 when the crash trucks arrived on scene, there were severely injured people strewn over the 1/2 mile of wreckage path that there was. The people who were thrown from the wreckage, as I discussed before, as well as many still trapped in the wreckage itself, were primarily in the wing centerbox section aft to the tail. This section of the wreckage was upside down and on fire, yet there were numerous survivors still trapped inside either hanging in their seats, or on what was now the ceiling of the interior of the upside down wreckage. As the P-4 and P-19 moved in, they began a mass-application of AFFF foam on this portion of the wreckage, knocking down the fire with the foam blanket but not fully being able to extinguish it before running out of foam. The P-19 ran out of foam first and began applying Halon, while the P-4 continued its foam attack while a firefighter from that truck deployed a 1-inch handline and began moving in to attack the portions of the deep-seated fuel fire that the trucks couldnt reach, as well as begin getting survivors out of the wreckage of the forward-center wingbox area; with 10-15 pax being rescued. At this time, the P-18 tender was ordered by Chief Hathaway to proceed forward and resupply the P-4 and P-19. The P-18 firefighter pulled in-between the two ARFF trucks and began hooking 2.5 inch supply lines from the tender to each ARFF truck, however when he opened the tank-to-pump valve and throttled-up the pump to the full 500gpm flow rate to transfer water, nothing happened. The PVC stiffener had rotated under the full pressure of the pump and blocked the tank water line, with the firefighters being unable to realize what was wrong. 8 minutes passed as they tried to rectify the problem.......7 minutes went by with no firefighting going on as the P-4 truck ran out of water and dry chemical (the exceptions being the small P-13 ramp chemical truck still firefighting, and the P-10 rescue truck still attempting rescue ops), and the balance of the time was spent unhooking the P-18 tender from the ARFF trucks, backing it out from the scene, and calling City structural fire trucks forward to transfer their water to the ARFF trucks as now ad-hoc water tenders. By this time, the fire that had been knocked down re-intensified as it cooked off the now-unsupported foam blanket and began to burn intensly, propogating rapidly into the fuselage area where the passengers were still trapped, as fuel began to run into the cabin area. It took a further 2 hours to fully extinguish the fires aboard UA232.
Unfortunately, it was found later that 35 people located in the center wingbox area had survived the accident, but died of smoke inhalation and thermal burns, 24 of them not even having any signs of blunt-force injuries of any type. The rest of the injuries being from blunt-force trauma from either the wreckage itself, or being thrown from the wreckage. Had the problem with the P-18 water tender been known, the ARFF trucks could've been resupplied in a timely manner and the foam blanket supported, keeping the fire knocked down and allowing rescue ops to continue. Unfortunately, this problem wasn't widely known, and weekly tests of the trucks were required to only test their ability to pump, not their ability to pump at full rate. The full rate test was done at the factory pre-delivery, but not done in the field in order to not stress or shorten the life of the water pumps on the trucks. Following investigation of the P-18 fire trucks, it was determined that the internal water-pipe stiffener was too short and of a smaller diameter, allowing it to rotate within the hose itself at very high pressures. Of the 210 P-18 fire trucks the USAF owned, 10 were found to already have this deficiency. Subsequently, the trucks were modified with an internal hose stiffener that was longer and of a 4-inch diameter much more closer to the hose size of the tank-to-pump hose, to prevent this anomaly from ever occurring again.
Pics below....top to bottom: Oshkosh P-4 1500 gal ARFF truck, Oshkosh P-19 1000 gal ARFF truck, Landoll P-10 rescue truck, Dodge P-13 ramp chemical truck, Kovach P-18 ARFF water tender
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