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Kick the tires.

We were scheduled for a flight with a full mission crew and enough gas for nine hours. We expected good weather the entire flight. The mission included a planned wire-out in an op area over the water.

The copilot was in the left seat and I was in the right seat. We had a third pilot, but he was not qualified to participate in a critical phase of flight. At about 100 knots on the takeoff roll, the copilot felt unusual control forces that required rudder inputs. The aircraft began to pull to the left. The copilot gradually increased right rudder input until he had slightly overcompensated. After he took out some rudder input, the aircraft again slightly pulled to the left. With winds negligible, using 80- to 90-percent rudder input was not only out of the norm, but also was uncomfortable.


The decision to initiate an abort was 50/50. With a maximum abort speed of 122 knots, the time between recognition and a potential abort decision occurs within seconds. Even with the odd inputs, we still maintained centerline. As the aircraft commander, the rudder inputs felt as if the copilot was dancing with the pedals, but because we were on centerline, I decided to continue the takeoff. I noticed the aircraft felt jerky, but my decision-making process was hampered because I didn't have direct control of the aircraft.

As we rotated and started to clean up the aircraft, our communications crew was the first to notice an acrid odor. As the fumes intensified, they smelled like burnt rubber. Seconds after the call was made to the flight deck, we picked up the smell. We were passing through 2,500 feet on our climb-out, and had just received clearance to climb to 15,000 feet.

I immediately directed everyone to get on oxygen and initiated our Fire, Smoke, or Fumes in Aircraft Interior checklist. I called ATC and told them we'd level off at 4,000 feet because of the fumes in the aircraft. I requested a vector to a radar downwind in case we needed to make a quick landing. ATC complied and gave us a downwind vector. We engaged the autopilot to help with our situational awareness.

As we leveled off, the checklist was activated. The cabin sweeps yielded no indications of overheating, smoke or fire. Our flight engineer began working the outflow valves to help dissipate the fumes. Within a minute all indications of fumes had vanished. I secured from the checklist even though we still had not identified the source. I gave instructions to stay vigilant in case the fumes returned.

The copilot and I thought we'd had a tire issue because of poor aircraft controllability and a smell that resembled burnt rubber. Because we already had oriented our aircraft for an emergency return, we asked tower for a low approach to inspect our gear. Tower said that runway 30 would be best for their view and cleared us for the visual approach. We completed our low approach. Tower reported that all indications looked normal. We determined that we had no inflight problems and continued.

Because we suspected a potential flat-tire issue, we immediately scratched the idea of any touch-and-goes. However, we could not find a reason why not to continue with the mission; we still had 8.5 hours of fuel onboard. Landing heavy was the least practical option and would only compound the issue. Dumping fuel appeared to be needlessly rash and unnecessary, as our situation did not indicate we needed to land immediately. We had 3.5 hours of fuel to burn down to reach landing weight, so we didn't think flying over the local area had any safety advantage over flying our intended mission profile. We decided to fly the mission, RTB, and full stop at our normal landing weight.

After completing work in the op area, we headed back to base and read the Landing with Flat Tires and Ground Evacuation checklists. The Landing with Flat Tires had one sentence that immediately stuck out, and it also happened to be the first one: "If any or all tires are flat, land the aircraft normally with the gear down. Reduce gross weight and landing speed by performing FUEL DUMP checklist."

There is no further guidance provided in NATOPS. It just tells you to reduce weight by dumping. At first glance, I did not think dumping would be necessary. We would land with normal procedures (which happened to go with my original logic to not dump). However, the more the copilot, the flight engineer, and I talked about it, the more uncomfortable we got. We did not know the problem with the aircraft.

In addition to tower's report that our gear looked normal, our flight engineers also inspected the gear through the landing-gear-inspection windows. They found nothing out of the ordinary. Although our gut feeling had told us the takeoff did not feel right, we simply had to assume that something was wrong. Generally, you can't go wrong by erring on the side of caution.

One visual inspection that could not be made by us was of the nosewheel tires. The viewing window only indicates the alignment stripes, not the gear itself. I decided to treat the aircraft as if we had a flat nosegear tire. Even though the copilot had right rudder in, we did not want to try and "game" it by thinking we had a left main tire out, and try land to the right of centerline. For all we knew, the aircraft might veer to the right on landing. With only the visuals on the mains, we needed to increase our odds by preparing for a flat nosegear tire. This decision assumed that tower could identify a shredded or blown tire. However, not all flat-tire conditions can be visible from that distance. We went with the safe bet: aim for centerline, keep the nosegear off-deck as long as possible, and anticipate the original tendency to veer back to the left.

We had discussed several times whether to dump fuel. It was possible we could go off the runway, maybe not a great chance, but enough to make sure we were in the best possible configuration. We had no reason to compromise on such a huge safety concern. The lighter we are, the slower we can get, and it's less fuel to turn us into a fireball screaming off the runway. The checklist said to dump, but not how much. I interpreted that as aircraft-commander discretion, and chose 25,000 pounds of total fuel remaining, which is one hour of flight time. This would make the jet light enough, but also give us options if the situation changed. If we didn't reduce weight, we would land just below maximum landing weight. We already had extended our crew day past 12 hours, and I believed flying another three hours to burn gas was not smart. I felt fatigued and knew it was time to get on deck while we still were reasonably fresh behind the controls.

WE DECIDED TO RUN the Fuel Dump checklist, get vectors to the ILS and set up for a full stop. The crew prepared for a possible ground evacuation. After an uneventful approach, I landed using normal procedures with the exception of holding the nose tire off the ground, as stated in the Nose Gear Tire Flat procedures. After applying max braking, the control forces felt normal. We came to a full stop, and were instructed to stay on the runway. The fire fighters inspected the jet, along with our flight engineers. Everything was found to be safe, and we taxied to our line.

During postflight, we found damage to the right nosegear tire. There appeared to be burn marks and abrasion lines on the right side of the tire, and also a quarter-sized chunk of rubber missing. We still do not know why the control forces acted the way they did. Our best guess is that the nosegear was somehow cocked to the side and created friction. We don't know why that much rudder was needed.

The copilot and I are the senior qualified guys in the squadron. Things could have gone differently had there been less qualified pilots in the seats. We were not even past 3,000 feet on climb-out when we had everyone on oxygen, a handful of jet, ATC constantly yammering at us, and were trying to run an emergency checklist. Events happened fast and furious, and we had our hands full.

Another key point to understand is that an actual situation does not always go like our simulated emergencies do. Fortunately, we were in the takeoff phase and everyone was fresh and alert, which made running the checklists more efficient.

The decision to abort is another critical part of this scenario. The time between 100 and 122 knots comes quick. We simulate aborts all the time, but normally you have an obvious failure or secondary indication. I don't recall ever having to abort for unusual rudder inputs. Not everything is going to happen like in the simulator. We kept centerline, and a couple potatoes later we were airborne. Had we felt a problem at 60 knots, we probably would have aborted the takeoff. There was no clear reason necessitating an abort, which made the decision that much more difficult.

I want to emphasize is the importance of CRM. The decision to dump fuel wasn't our original plan. Don't be afraid to change your way of thinking or logic. Most pilots may be uncomfortable with that idea. At face value, the decision seems odd considering that we elected to do a mission flight and then dump rather than dump and land immediately.

We scrutinized the meaning of that checklist during the remainder of the flight and put safety ahead of everything else. I signed for the jet and was responsible for the crew's safety. As the flight went on, I felt this was the safest decision.

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Title Annotation:ORM corner
Author:Cook, Dan
Date:Sep 1, 2012
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