LAX07TA051

The airplane sustained an in-flight loss of the right elevator during an in-flight upset while maneuvering. The pilot was flying the airplane from the left seat. The mishap airplane rendezvoused with another Learjet to begin a series of profiles for flight testing. The crew noted that the horizon was very difficult to discern. While maneuvering for the second set of data points, the pilot lost sight of the other airplane, and rolled right to remain clear. His vision was impaired by the glare from the sun, which delayed his recognition of the airplane entering an unusual attitude. The pilot initiated recovery with the airplane in an estimated 70-degree right bank, 50-degree nose down attitude, and an airspeed of 380 KIAS. During the dive, the crew noted that the airplane was definitely shuddering, but did not recall any rolling tendencies or vibration of the control yoke. The crew conducted a controllability check by slowing it to 150 KIAS and lowering the landing gear. Again the airplane exhibited no unusual flight characteristics. The remainder of the flight and landing were uneventful. During post flight inspection, the aircrew discovered that the right elevator was missing.

On December 1, 2006, about 1035 Pacific standard time, a Learjet 36, N26FN, sustained an in-flight loss of the right elevator while maneuvering off the coast of San Diego, California. L-3 Communications Flight Capital LLC was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. The airline transport pilot, the commercial rated second pilot, and one passenger were not injured; the airplane sustained substantial damage. The local public-use flight departed North Island Naval Air Station (NZY), San Diego, about 0930. Visual meteorological conditions prevailed, and no flight plan had been filed.

The operator submitted a written report.

The pilot was flying the airplane from the left seat. The airplane rendezvoused with another Learjet in W-291, approximately 100 nm west of NZY, to begin a series of flight profiles for the testing of a Common Aviation Command and Control System for the Department of Defense. Though visual meteorological conditions prevailed at the time of the accident, the crew noted that the horizon was very difficult to discern.

The first profile was flown with the airplane 1,000 feet below and slightly in trail of the other Learjet. The run was uneventful except for increasing communications difficulties with the test controllers as the flight proceeded down range. While attempting to reestablish communications with the test controllers, the high Learjet began a left-hand orbit. The pilot (of the mishap Learjet) maneuvered to a co-altitude in trail position to maintain sight of the other airplane and facilitate the setup for the next profile. During the maneuver, the pilot lost sight of the other airplane, and rolled right to what he perceived was 25,000 feet mean sea level (msl), 270 knots indicated airspeed (KIAS), and 90 percent N1, respectively. Unable to see the horizon or the other airplane, he attempted to transition to instrument references. But his vision was still impaired by the glare from the sun, delaying his recognition of the airplane's attitude. The copilot had been heads down in the cockpit, and when he ultimately noted the airplane's increasing bank, assumed that the pilot was maneuvering to avoid the other airplane. The pilot initiated recovery with the airplane in an estimated 70-degree right bank, 50-degree nose down attitude, and an airspeed of 380 KIAS.

The pilot moved the thrust levers rapidly to idle, rolled to a wings level attitude, and began the dive recovery. He noted that the airspeed seemed to stabilize at 380 KIAS, and the pull was not abrupt. Both crew members felt that the pull up was completed smoothly without excessive G force. During the dive, the crew noted that the airplane was definitely shuddering, but did not recall any rolling tendencies or vibration of the control yoke. The crew did not recall any unusual noises other than the loud wind noise.

The equipment operator seated at the midpoint of the cabin noted that the wind noise and the shudder continued to increase in intensity until partway through the dive recovery. At the end of this time, he heard a very loud bang and felt a large shudder, after which the airplane's shuddering almost immediately ceased. Everything seemed to return to normal "as if nothing happened."

The dive recovery was completed by 16,000 feet msl, and the aircrew noted no unusual handling qualities as the airplane slowed to 200 KIAS. The crew conducted a controllability check by slowing it to 150 KIAS and lowering the landing gear. Again the airplane exhibited no unusual flight characteristics. The remainder of the flight and landing at NZY were uneventful.

During post flight inspection, the aircrew discovered that the right elevator was missing.