Sideslip

muk_yan_jong · Nov 20, 2015

I remember seeing one of those HxChannel Plane crash shows where a jetliner pilot (who was also a glider enthusiast) was able to salvage a powerless descent with a masterful sideslip...

but THIS must've been a true pants-filling moment.

Air Force loses $115 million gunship to a 'sideslip' - CNNPolitics.com

My father is a pilot and talked of a LOT of fun maneuvers in his Piper Cub, but something this big and radically inverting???

Bob Parks · Nov 20, 2015

muk_yan_jong said: ↑

I remember seeing one of those HxChannel Plane crash shows where a jetliner pilot (who was also a glider enthusiast) was able to salvage a powerless descent with a masterful sideslip...

but THIS must've been a true pants-filling moment.

Air Force loses $115 million gunship to a 'sideslip' - CNNPolitics.com

My father is a pilot and talked of a LOT of fun maneuvers in his Piper Cub, but something this big and radically inverting???
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There are two kinds of slips, a side slip and a forward slip. The side slip can be dangerous if speed gets too low and the airplane stalls. It is accomplished by lowering a wing and applying opposite rudder, keeping the nose level or slightly high. A forward slip is started the same way with one wing down and opposite rudder fed in but the nose is lowered, not held level or pointed up. I can remember the movements with the stick going towards the corner the lowered wing and gently feeding in top rudder. I used it many times landing at short or unfamiliar strips or where the approach had tall trees at the end. I always preferred the forward slip to shorten the approach instead of flaps.
Once after landing at our old field a young flight instructor wanted to know what"that maneuver" was when I landed. I told him that it was a slip and he responded that he had never heard of it and it looked dangerous. I'm saying it more and more now..."Times change."

MarkPDX · Nov 20, 2015

There have been a few incidents where the C-130 has gotten all upside down.... A friend was on a plane where (for unknown reasons) the other pilot yanked the throttles back and tired to get the props into reverse while in flight. There was a brief departure from controlled flight before things recovered but the crew was kinda pissed. Another incident which comes to mind is below.... Pretty crazy situation.

Wednesday, September 28, 2005
Crew comes together to save aircraft, each other

The world turned upside down April 12 for the 11 occupants of a KC-130T from Air Test and Evaluation Squadron 20 (VX-20) when, at 24,000 feet on a cross-country flight, a 200-pound life raft deployed from inside the left wing and snagged on the tail. With the raft functioning like a lopsided drag chute, the aircraft rolled inverted and began a spiraling dive toward earth.

Maj. Nathan Neblett worked to get the plane righted while dealing with a failure of the instrument that provided his primary reference for which way was up. In the back of the aircraft, loadmaster Sandy Hartkemeyer and five aircraft maintainers were turned into projectiles in the open tube of the fuselage, along with a storm of potentially deadly gear and supplies.

The operating procedures for the burly C-130 Hercules strictly prohibit "aerobatics of any kind (including those that produce a negative-G condition), intentional spins, excessively nose-high stalls, steep dives, and any other maneuvers resulting in excessive accelerations." Such deviations, it warns, can stress the airframe to failure, lead to unrecoverable loss of control, or both. In a matter of seconds, the plane had involuntarily broken every rule in the book.

In the cockpit, pilot Neblett was fighting for control; he had immediately disengaged the autopilot and was now making control inputs that his experience as a test pilot told him should arrest the spin. Copilot Dan Sanders, who had pulled the throttles back to idle, was scanning the instruments and fighting his instinct to reach for the yoke himself.

"It was a conscious effort; I had to throw my hands up," said Sanders, who accumulated 4,600 hours as a Marine Corps C-130 Hercules pilot before retiring as a major a year ago.

"Out of 11 people onboard, only two could do anything about it, and one of them had to let go," Neblett said.

Behind the pilots, flight engineer Wray Emrich had flown out of his seat and slammed off the ceiling of the cockpit; he later found wounds in his scalp that conformed to the arrangement of switches over his head. He managed to grab hold of his seatbelt and drag himself back down, then held on with all his strength during the violent ride, like a rodeo cowboy trying to stay on a bucking bull. Flight test engineer Ray Bacorn and navigator Craig Homer were hanging on as best they could, while everything that wasn't nailed down became airborne.

"The only thing that didn't move," Neblett said, "was our instrument panel."

Throughout the airframe, the noise was tremendous.

In the cockpit, everyone was shouting to be heard, Sanders said; his intercom switch was on the control yoke, which he could not risk grabbing.

Other occupants reported hearing the airframe groan under the strain of all the G-forces.

The most ominous sound for Emrich was the howling of the engines, though; the incredible onset of airspeed had caused the props themselves to over-speed, reaching 106 percent of their correct RPM. Flameouts were very real and deadly possibilities. But the engines held, a fact that Sanders attributes in part to the excellent responsiveness of the new Electronic Propeller Control System that was installed on the plane for testing.

In the C-130, engine speed and propeller speed are supposed to stay constant throughout flight; the actual velocity of the aircraft is controlled by changing the pitch angle of the propeller blades. The EPCS replaces the old hydraulic and mechanical system that controls propeller pitch, instead using electronic sensors and actuators that should be more reliable and respond rapidly to inputs and changes. No one, however, had ever anticipated validating the new system's performance under such dire circumstances.

As the altitude wound away, Neblett managed to get the wings level for a moment, long enough for a glimmer of hope. Then, with the life raft still attached to the left half of the tail, the KC-130T went inverted again.

"I remember thinking, 'We're never going to come out of this," recalled Emrich.

"Twenty-two years flying in the Navy," thought Hartkemeyer, "and not even a year here at VX-20, and this is it."

Still, no one gave up. Neblett continued his work at the controls, applying the best of his test piloting expertise to regain control of the stricken tanker. At some point the raging airflow over the outside of the fuselage was enough to tear almost all of the life raft free. Neblett worked with Sanders, who had the benefit of a functional Attitude Direction Indicator, and somehow managed to get the wings level again. He pulled back on the yoke, and slowly the plane came out of its speeding dive.

When he leveled off, the altimeter read 15,000 feet. The entire episode had lasted less than half a minute, during which the aircraft's maximum rate of descent reached 29,000 feet per minute.

And still no one knew exactly what had happened or why, which meant no one knew if it was going to happen again.

Hartkemeyer tried to come up on the intercom, but her cord had been ripped apart at the connector.

"When everything stopped," said Emrich, "I couldn't hear anyone in the back. I needed to know the condition of the airplane and personnel, and no one answered."

Miraculously, though, none of the injuries were life-threatening. Despite having taken a terrible beating, Hartkemeyer assumed control of her part of the plane.

Neblett and Sanders concentrated on flying the aircraft and getting pointed toward the nearest airport, which actually involved turning the plane around. Focused on the task at hand on the flight deck, Sanders told Emrich, "I do not want to know if there's no plane behind us."

Sanders radioed the authorities at Tri-State Airport in Huntington, W. Va., to say that he had wounded aboard and would be making an emergency landing.

Later, Neblett would praise crew resource management - the right combination of good communication, situational awareness and sharing of the workload - for getting them all through the crisis. Landing checklists were lost somewhere in the wild snowdrifts of paper all over the floor of the cockpit, but procedures were nonetheless executed correctly.

A short time later, Neblett made an uneventful landing, taxied off the runway and shut down the aircraft.

"Once we hit the ground and cleared the aircraft you begin to come apart," said Emrich.

The day's work was far from over. In the aftermath of the mishap, various Navy and Marine Corps commands had to be contacted, the aircraft had to be secured for investigators, and the local and national media needed to be dealt with. Above all the crew and passengers - whose injuries included broken fingers and a variety of contusions and lacerations - needed medical care and lodging.

Neblett and the rest of the shaken survivors received a generous helping of West Virginia hospitality, particularly from airport officials and the local National Guard and Air National Guard.

It has been almost half a year since the incident, and today the same crew is flying the same KC-130T, which has been repaired and recertified, on test flights for VX-20. The mishap has become a learning opportunity, briefed to other aviators and maintainers, as well as a permanent piece of C-130 folklore. Neblett received his Air Medal in late August, for somehow writing a happy ending on a story that easily could have concluded with a memorial service.

"His aeronautical instinct, aggressiveness, and level head led to the remarkable recovery of a non-aerobatic aircraft from uncontrolled flight while sustaining absolutely minimum damage," his award citation reads. "Maj. Neblett's superb airmanship, decisive decision-making, perseverance, and loyal devotion to duty in the face of hazardous flying conditions reflected great credit upon himself and upheld the highest traditions of the Marine Corps and the United States Naval Service."
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Sideslip

muk_yan_jong Formula Junior

Bob Parks F1 Veteran
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MarkPDX F1 World Champ
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Sideslip

muk_yan_jong Formula Junior

Bob Parks F1 Veteran Consultant

MarkPDX F1 World Champ Lifetime Rossa

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Bob Parks F1 Veteran
Consultant

MarkPDX F1 World Champ
Lifetime Rossa