FB-111.net

The website dedicated to the FB-111A

Night time on the trim pad

It was a more or less typical night on the flightline at Plattsburgh Air Force Base, where during the early 80s I was an aircraft maintenance officer working the second (swing) shift. I was nominally in charge of making sure that our assigned lines aircraft that were scheduled to fly that night were ready to accept crews and go off to do their training. And after the airplanes had launched, there was always the cleanup work to do. Things such as checking on the aircraft in the phase, or inspection dock to see how they were coming along (since we were always short of airframes, this was of prime importance); looking in on the aircraft on the major maintenance dock called by the crew chiefs major malfunction, since this was the (sometimes) temporary home of the aircraft we used to cannibalize parts from to keep the others flying; and riding up and down the line, checking forms, getting out of the truck to stretch and walk around a bit, chatting with the guys as they went about their business, and maybe running an errand or two. Errands such as giving someone (or several people) a ride back to the branch, or to one of the docks, or to the inflight kitchen to (finally!) grab some food that is a polite use of the word! or whatever else came up.The radio crackled it was one of my bomber expediters, a maintenance guy assigned to drive a truck on the ramp to take the crew chiefs around to their aircraft. We usually had two trucks, one and two, for each flight of bombers and tankers, depending on the number of vehicles and people available (sometimes, we could run only one truck). The second vehicle was the gofer truck, which helped to take the load off one by freeing it to stay on the ramp while two ran the errands described above. Anyway, the flight was getting ready to do an engine run on the trim pad, and would I mind going down there and watching the airplane for a while? Of course, I wouldn't mind, and besides, it was regular policy for a supervisor to keep an eye on things while an operation with the chance of something going wrong, such as an aircraft tow, engine run, or putting an airplane in a hangar, was taking place. I gave the standard 'roger', copy over the radio and headed down to the trim pad. This promised to be fun. Trim pad meant afterburner, since we couldn't run a bomber in burner on the main parking ramp because of its proximity to the town. Plattsburgh and the base are virtually on top of one another. (Too much noise for the citizens!) But I loved afterburner engine runs anyway, lots of decibels and power!

The Plattsburgh ramp is in the shape of a long rectangle when looked at from above. When the 380th Bomb Wing was there, if you were looking straight down on the ramp, facing true south, the bomber and tanker alert force was parked on the extreme right, the FB-111s in the center, and the KC-135s on the left. There were about half a dozen rows at the extreme left, or true east, end of the ramp, right in front of Base Operations and the control tower, that were left empty to receive visiting aircraft. You followed the perimeter road that ran along the true north edge of the ramp down to Base Ops, made a sharp right turn, drove past the sound suppressor on the left, and followed the road to its end. Then you made a sharp left turn and followed the edge of the taxiway about an eighth of a mile down to an opening on the left. This was the entrance to the trim pad, a circular expanse of concrete surrounded by thick woods, with hooks embedded in the middle of the pad. These were for the tie-down chains to secure an aircraft, usually an FB-111. (We normally ran the tankers in their usual parking spots on the tanker ramp, since they didn't have afterburners, and their weight, plus standard wheel chocks and locked brakes, was enough to prevent forward movement). The bombers needed the extra precaution of being tied down due to the tremendous power of their twin turbofan Pratt and Whitney TF-30 engines, each of which in afterburner put out well over 20,000 pounds of thrust. The trim pad was a lonesome spot, especially at night. There were no lights down there, you had to bring a light cart, or carts, with you, plus flashlights. But because of the trim pad's isolation, we could run a bomber down there in AB as long as we needed to. I always wore my ear protection on the ramp in any event, but especially on the trim pad, and sometimes I even stuck a pair of the insertable ear plugs in my ears to wear under the ear defenders. Even minimal exposure to the something like 150+ decibels of roaring AB will melt your ear wax in seconds!The airplane was already there. Staff Sergeant James D. Murray (it was said that his middle initial, D, was for 'Dirty') was attending to the chores of getting the airplane ready to run. Jim Murray may not have been a poster child for an Air Force crew chief, but he was one of my best. He was a tough street kid from Queens, with the accent and the attitude to go with it, but he knew and loved the 111 like few others did. He was especially fond of his own airplane, 243, but any bomber under his care got essentially the same treatment. And Jim was not about to let this particular airframe run away from him on the trim pad that night. He was one of those guys that you always had to look out for, because he had a hard time staying out of trouble, but he was so good at what he did for a living that you did your best to keep him around. He was the type you'd like to have with you in a shooting war, because he knew his job and what we were there for. Jim greeted me with a half-wave and his trademark toothy grin. As we walked around the airplane we exchanged pleasantries about the usual stuff. It was a beautiful night, temperatures in the 40s, about 11 pm or so, a great time to cut loose and make some big noise with a powerful airplane,enough to wake the dead if there were any around!

When we were satisfied all was in order, Jim fired up the ground power unit, climbed into the cockpit, and settled into the left seat. I headed back to my truck, snugging my ear defenders tighter over my ears. I took my seat in the big '74 Chevy, parked in such a way that I was looking directly at the aircraft and able to see clearly out from both the nose and tail. Jim called the tower and advised them of the engine run, and I rolled the truck windows up tightly. I pulled my ear defenders aside so I could listen for at least a couple of minutes to that mesmerizing sound of those big fans spooling up. I always love to hear the sound of aircraft engines, as long as they aren't too loud, and now I could let myself relax and enjoy the show. Jim Murray was very much in charge, knew what he was doing, and as far as I was concerned, we were all as safe as we could be.The ground power start unit was actually a miniature jet engine that provided air under pressure via a rubberized canvas hose (a little less than a foot in diameter) to the engine that would be started first, usually the left (or number one) engine. The hose was hooked up with a fitting that securely held the hose in place so it wouldn't blow off when Jim allowed the air to go surging through it to the waiting engine. All it took to spin that big, heavy main compressor/turbine around was a mere 35 pounds of pressure. The engine's balance was that delicate and that smooth! 
The start cart was whistling along when Jim opened the valve to let the airflow go to the engine. As the air entered the aircraft it blew out of the bottom of the fuselage through an overboard vent. That air was very hot. You didn't want to be anywhere near that vent while this was happening, or you'd get burned quickly and easily. You could tell when the air was being ducted directly to the engine when the loud rushing noise caused by the venting air would stop as the vent closed, the hose would jump a few inches, and the hot compressed air flowed directly onto the first stage compressor to start it turning. A blast of air through the engine, then the compressor would begin to spin slowly, with a deep, bass 'whoooomm', then faster and faster, and the sound would gradually change from bass to tenor as the revolutions built up. When the engine turns reached about 40% power the combustion cans surrounding the engine core would light off the fuel-air mixture inside, signifying ignition, and the hot exhaust gases would burble out the back of the tailpipe. Now the engine was on its own, and as the revs spun faster and faster a distinctive, chilling howl went up as the engine sucked in air to feed combustion and sustain itself. The revs had reached about 70%, which was idle speed, and Jim 'goosed' the throttle quickly forward, then back, causing a slight break in the sound of the engine. (He and a couple of the other guys liked to do that, just to test throttle response). Same procedure for the other engine, except that this time starting would be accomplished by means of a 'football' valve (so called because of its shape) located between the engines. Bleed air from the already running engine would flow to the other through the football valve, spinning the compressor and lighting off the engine in the same manner as the first. The right engine turned over smoothly and lit off the way it was supposed to, and then Jim shut down the compressed air from the start cart since it was no longer needed. Now the aircraft was running with that characteristic steady dull scream of engines at idle power. Only the TF-30 sounds like this, and if you listen to an earlier model F-14, which had essentially the same core engine, you'd hear the same thing. I set my ear defenders back on firmly again, because things were about to get very loud very quickly!Jim smoothly moved both throttles to full military power, or 100%, and the steady scream escalated to a louder, heavier roar as the engines strained to push the airplane forward, held back, of course, by the chains wrapped around the main landing gear assembly and secured to the pad hooks. He let the engines run at military for about ten seconds or so, then he lifted the throttles over the hump, the stop on the throttle quadrant that prevented accidental movement of the throttles to afterburner and now all hell broke loose! There was a momentary hesitation, no more than two seconds, as the spray bars in the tailpipes sprayed the hot gases flooding out the rear of each engine with fuel (and those gases literally caught fire), then a tremendous, booming thunder ripped the air. White-hot, bluish-pink tongues of flame poured out of the tailpipes, growing swiftly in length as each additional zone (or stage) of afterburner kicked in. With all five zones of AB now roaring full bore, those fiery tongues extended a good twenty feet in length!You have to hear and see this for yourself to gain a full appreciation of it, words do not do justice to this singular display of raw power. The heavy thunder of the engines tore through the night and blasted everything behind the tailpipes for at least 100 feet with searing, 1200 degree air. The inside of the truck had become a miniature sound chamber. I felt the concussion of the afterburners pressing perceptibly on my chest. If it weren't for the ear defenders tightly clasping my head, I would've been deaf in a matter of seconds. The truck vibrated, buffeted, and shook as if caught in a hurricane. Inside the aircraft, Jim scanned the cockpit instruments, checking for anything unusual, any red lights that told of impending trouble, found none, and eased the throttles back out of AB. The pounding, shattering, thunderous roar dropped noticeably and smoothly with an audible sigh, kind of a long 'huuuuhhhhhhhhhh' as the engines returned to idle. It sounded as if the airplane was letting out a mechanical sigh of relief! The truck stopped shaking, the pressure on my chest let up, and it seemed almost quiet as the dull scream of idle returned. But not for long! The heavy roar, the booming blast, those Bunsen burner-like tongues of fire, and we were back in AB again. More shaking, more buffeting, more concussion, the airplane's wings and tail assembly vibrated and shook with the power of the engines. Forty thousand-plus pounds of thrust thundered their chorus over the pad ramp, into the woods, and around the dark countryside. Good thing those engines were pointed towards Lake Champlain instead of towards town. As well as we got along with the good citizens of Plattsburgh, the switchboards would've lit up like Christmas trees with the complaints!

Jim cycled the engines back and forth between military and AB a couple more times, let them return one final time to idle, pushed up the revs to about 90% to 'scavenge' the engines of any excess oil or other impurities, then he chopped the throttles to cutoff. The engines whined down, the big turbines quietly growling as they spun slower and slower, then the blades clattered to a stop. Only the whistle of the start cart remained. Jim climbed down from the cockpit, using the step peg as before, then shut down the cart. As the whistle faded away, the silence was practically deafening. Jim grinned again, he knew how much I appreciated the power display! and said that all checked good. We unchained the airplane and set it up for a tow back to the bomber ramp. I climbed again into the truck and called in the results of the run. Jim Murray would remain with the airplane to ride the brakes during the tow. I hung around for a while chatting with him until the expediter truck and tow tractor with an attached tow bar came around the bend in the taxiway and headed towards us. When all was done, I moved out ahead of the airplane and the vehicles and drove back to the branch to get ready for turning over the shift to the third shift crew. It was a little past midnight, and after the excitement of that engine run I was finally getting a bit tired. But we had one more airframe in commission, and we at least had some time for a little fun to go along with that ever-present work!. By Kevin McAndrew.

Back from the trim pad

It was a cool damp March morning on the Plattsburgh flight line. It was going on 04:00 and all was calm, the morning's flyers were about ready. I was driving Red 2 with three other crew chiefs that were taking a break. I had just come back from catching an F-106 that Job Control asked us to catch as we had no one else around to do it. Awesome jet, it was slightly foggy and the F-106 looked like a predator of the night cutting through the fog. When that jet shut down it's engine, it made the most awesome sound when it ran down to a stop.The guys wanted to see it so I said "What the hell!". We got down by it and got out to look around and what did we find? A drag chute. So one of my guys grabbed it for a keep sake and said "That jet don't need it for take-off!". We agreed about that but we didn't think about the landing. So we got back in the truck and went down to the trim pad as we had a jet down there and we were most of the way down that end anyway.We checked out the jet on thr trim pad and found out that it was Tango Uniform (Tit's Up- dead on it's back). That was 680249's norm. So we started our way back to teh flight line. I came up with a great idea. Let's play F-106! So I told my chute rigger to rig that bad boy to the tow hook in the back of Red 2. I asked the guys "How fast do you think we have to go to get a good chute?". We cam up with 40-45 mph so off I went and when we got up to 45 mph I gave the order to deploy the chute. "Boy did it deploy!". It opened with a crack and the trcuk kept going, we did not slow down at all. But the rear bumper sure came to a noisy halt about 150 feet behind us.We all said "Holly S#$%" at about the same time and teh things that went through my head like it was great to be a Sergeant. Nothing like an Article 15 to screw you out of stripes and money. So I came up with another great idea. I asked my chute rigger and safety wire specialist to get the bumper back on the mighty Red 2 for a mission. A mission to save the great F-106 combat team from a hard landing. So the bumper was on the truck and we were on our way.We got back to the line and parked by the AGE equipment between the two flight shacks that were used by Red Section and White Section. OMS Super was over there parked and facing us doing paper work. We had a plan and I hoped it would all work out. After about 10 minutes, we had our chance. White 1 called White 2 to get a mule and wouldn't you know it, we were right by one. I gave White 2 a call and said I was right by one and would help them out as they had a few broke jets and Red Section was sitting good. Teamwork! We backed up and hooked it up. Prior to moving, I called over to OMS Super to have him move back a little. He looked up just in time to see Red 2 get in the six by that mule with the stuck brakes. You can never trust that AGE equipment. That morning, we all learned one thing! We should have played a different game!  By Jim Murray,