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[Wreckage of F-117A #793.(USAF Photo)]

Aircraft Losses

Maj. Bryan "B.K." Knight (USAF)
Bandit #437 (Jan 11, 1994)
Sept. 14, 1997
F-117A #81-793
Cause: Missing wing stiffener bolts

[Wreckage of #803 burning.()] On Sept. 14, 1997 at about 3 p.m. F-117A #81-793 with approximately 11,000 pounds of fuel aboard crashed into A house about 100 feet from the water of the Chesapeake Bay, near the Glenn Martin State Airport near Middle River, Md., about 13 miles east of Baltimore.

It was making its third and final pass of the airfield at the Chesapeake Air Show in front of 12,000 people and was preparing to return to its base when the crash occurred. First the pilot did a straight and level pass at 400 kts and 500 feet. Next, a straight and level pass at 300 kts and 500 feet to give those attending the airshow a better look at the F-117A Nighthawk. The final pass was a 45-degree arcing pass at 380 kts and 600-700 feet, providing a plan-form view of the aircraft, optimum for pictures.

[F-117A #793 one week before the accident.()]

The aircraft was being piloted by Maj. Bryan Knight, who safely ejected and was taken to Malcolm Grow Medical Center at Andrews Air Force Base, Md., for treatment of minor injuries to his neck and back and for observation. He was released the next day. Knight is an instructor pilot in the 7th FS with more than 2,770 flying hours, including 500 in the F-117A. The F-117A had left Hancock International Airport at Syracuse, N.Y., and was performing at the airshow while en route to Langley AFB, Va. It was one of two F-117As temporarily located at Langley to support community and military airshows in the eastern United States. Aircraft and personnel serve in 60-day rotations. This rotation for the mishap aircraft and Maj. Knight began the first week of September. The previous day, the pilot and aircraft participated in a flyby at Arlington National Cemetery before arriving at Syracuse.

[Maj. Knight waited until the leat instant to eject.()] The aircraft had started the 15-deg. climb from the 380 kt. flyby at 600-700 ft. when the left outboard elevon made several large deflections up and down. The oscillations deflected the left wing, which broke off 2.5 ft. inboard of the elevon. The aircraft rolled 90 degrees left within 0.8 seconds, then sharply pitched to a high angle of attack. A second later, the main landing gear was visible in the down position, probably due to the high loads or loss of hydraulic pressure. Under 3 seconds elapsed from the start of large elevon oscillations to the gear being down. After the F-117A pitched to the high angle of attack, it appeared unstable and out of control. The aircraft began to tumble, the pilot ejected, and the plane hit the ground in a fireball and large cloud of black smoke about 5 seconds after the ejection about one mile from the threshold of Runway 33 at Martin State, slightly south of the runway's extended centerline.

Andy Kunkowski said he was watching the show from a small boat near the shoreline and immediately went to the scene of the crash and spoke to the pilot. "He said he was truly sorry about what had happened and said he tried to pull it out," Kunkowski said. "He wanted to land this thing in the water, but couldn't."

"He said everything was fine until he started to make an incline, and at that point he realized the rear wasn't doing what it was supposed to," Kunkowski said.

Four people on the ground -- one man and three women -- sustained minor injuries, said Steve Gisriel, a captain with Baltimore County's fire department when the aircraft exploded on impact destroying a house, a garage and two motor vehicles, and damaging two other homes, Gisriel said.

The Recovery Efforts

Over 35 pieces of rescue and emergency equipment were sent to the scene and the fire was declared under control at 4:46 p.m. after firefighters smothered the fire with foam. Authorities declared the crash site a "national defense area". Military crews erected an 8-foot-high tarpaulin around the site and sprayed pieces of the plane with a wax like substance to prevent tiny pieces of the damaged aircraft from becoming airborne and drifting out of the containment area. The substance looked just like hair spray. It was packaged in cans about the same size and shape, and looked about the same when sprayed onto the surfaces. It put down a thin, slightly shiny coating that dried quickly. Such extreme measures were taken to preserve the military's secret RAM technology.

[Local residents were evacuted by the USAF. ()] "There was military everywhere. This road was full, the sky was loaded. I tell you it was something," said Paul Canatella, standing in his driveway less than a 100 yards from the jet's mangled canopy, which was watched by two armed military guards. "I've never seen anything like it," Canatella said. "You name it they were here."

Film was confiscated from members of the media who were detained for about 1 hour, including Associated Press photographer Roberto Borea, who had chartered a boat to take him to the neighborhood.

As soon as we stepped on shore, the military was there and that was it," Borea said. "Had I chosen not to surrender my equipment, I would have been taken into custody."

Capt. Drew Sullins, a Maryland National Guard spokesman said Monday the film and equipment would be returned and the seizure should never have taken place. He also allowed pool photographers on the scene for a few minutes under tight military supervision.

Authorities also ordered the evacuation of a three block area as a hazardous materials team scoured the crash site and searched for fragments of the plane. About 50 people were forced from their homes and were being sheltered at a local fire department. Hours after the crash, 22 rescue workers, including firemen and a police officer, had to be taken to the hospital complaining of breathing problems, mild nausea and headaches, Mark Hubbard a battalion chief of the Baltimore County Fire Department said Monday. None was admitted. They were part of an initial response group of 125 which raced to the crash site, Hubbard said. Authorities believe the rescue workers' breathing difficulties were related to smoke from carbon fibers which make up the fuselage of the top-secret F-117A, he said.

The Air Force allowed the residents to return to their homes on Sept. 17th (except for those that lived in the "National Security Area" which included several houses and yards - since the aircraft descended almost vertically at relatively low speed, the wreckage was confined to a pretty small area), the aircraft was cut in pieces for removal starting on Sept. 18th, and recovery operations were completed on Sept. 21. After seven days of sifting through the wreckage, civil engineers accomplished the site cleanup process Sept. 22. Cleanup involved raking out the area, picking up loose debris and testing the soil and water for contaminates. The next day, Air Force people removed their equipment and terminated the National Defense Area surrounding the crash site, effectively turning the area back over to the residents and local authorities. Since then, the Air Force has paid local residents somewhere close to $1 million in compensation.

"I felt it (the recovery operation) went outstanding," said Lt. Col. Jim Coleman, on-scene commander, Maryland Air National Guard. "It's a prime example of how total force works. You integrate people from various units and put them in an environment where they have a goal, and people step up to the challenge."
In addition to the initial emergency response forces, Coleman's team consisted of more than 300 people from units such as the Maryland Air National Guard, 89th Airlift Wing at Andrews AFB, Md., U.S. Navy, U.S. Coast Guard, Baltimore County Police, Marine Police and Fire Department, Bowley's Quarters and Middle River Volunteer Fire Departments, the American Red Cross, Department of Natural Resources, the National Safety and Transportation Board, the FBI and Air Force Office of Special Investigations.

"It was a learning experience for everyone that was involved," Coleman said. "We learned as a team. We were able to take advantage of all the skills available to get the job done."

Inside the Cockpit

In the October 13th, 1997 issue of the "Air Force Times" the following interview with Maj. Knight was published:

"In the instant before his F-117A Nighthawk began falling apart above thousands of people, Maj. Bryan Knight had no cause for worry. Having completed the last of three scheduled flybys above the crowded air show in Maryland, the 12-year Air Force pilot ascended into the blue sky, leveled out at 10,000 feet and turned south toward Langley Air Force Base, Va.
"It was a beautiful day to fly," Knight said in his first interview since the Sept. 14 crash. "I thought it was over and I'm on my way home."
Without warning the plane shuddered with "a pretty rapid vibration" and veered sharply to the left, he said. The violent acceleration jerked at Knight and "G-forces pinned my head down and forward," he said.
"All I could see was the lower part of the instrument panel. I thought maybe I had had a midair" collision, he said.
[The aerodynamic forces tore #793 apart.()] Knight had no way of knowing that his stealth fighter, one of the world's most sophisticated aircraft, was disintegrating around him.
"The aircraft was rolling right. The nose was pitching around. My impression was that the aircraft wasn't moving forward," he said.
Looking outside the cockpit, Knight saw only land and water, but he "knew where the people were," he said. "That was my concern. I realized there was a good chance the aircraft couldn't be flown out of this."
Working the stick and throttle, Knight fought the plane's motions. As the aircraft descended, he struggled to guide it toward water, he said. For that, some have called him a hero.
Defense Secretary William Cohen commended Knight in a speech for staying "with that aircraft until the very end."
In retrospect, Knight is unsure if his efforts accomplished anything.
"I don't think my control inputs had an effect," Knight said.
Five seconds before the plane crashed and exploded, he ejected.
"That was probably the hardest decision I ever made in my life," he said. "I dreaded having to pull those handles. I realized I had to get out right now or I may not survive."
As he parachuted to ground, Knight watched the plane descend through trees, land in the front yard of a residence and explode into a fireball.
"I felt I was headed for the fireball. As fate would have it, I got blown a little bit left of where the fire was," said Knight, who touched down about 150 feet from the burning wreckage.
Knight suffered only minor injuries from which he has recovered.
The 36-year-old pilot insists he in not a hero.
"Absolutely not," he said. "I was doing exactly what I was trained to do. Every member of my squadron would have done the same thing. In no way am I a hero."
The real heroes are the people who endangered themselves when they rushed to his aid, Knight said.
"They were concerned if I was all right even though I had just sat an airplane in their neighborhood," he said.
The crash has not dampened Knight's enthusiasm for flying or his faith in the F-117, he said.
"It's an outstanding airplane. I'd really like to be flying it right now," he said. "I have a lot of faith in the aircraft and the whole F-117 community."
Nor will the recent spate of military crashes unnerve other pilots, he predicted.
"No pilot gets in a jet and thinks about crashes. That's fatalistic. We're pretty positive people," he said. "I want to go back to flying and being an instructor.""

The Cause

The December 22, 1997 issue of Aviation Week reported that "The final accident report stated that four missing fasteners caused the crash and required inspection of those fasteners was missed six months earlier. The report found that the maintenance records of the 49th FW were incomplete, that the fastener inspection was not accomplished due to "contractual and budgetary constraints," and that no group was tracking whether required "time compliance directives" were being completed by the due date. The missing fasteners helped attach the elevon hydraulic actuator to local wing structure. Their disappearance reduced actuator-to-elevon stiffness, which earlier had been found to cause elevon-wing flutter.

The actuator attaches to a spanwise "Brooklyn Bridge" I-beam that transfers load to the ribs. The actuator bay is accessed by removing an upper wing skin panel. The upper and lower caps attach to the ribs with L-brackets, and the vertical web attaches with T-brackets. The L-brackets are attached to the upper cap with one Taper-Lok and four Hi-Loks fasteners. The double hides the four Hi-Loks, and these were missing. Evidence showed that three L-brackets and both T-brackets were broken, allowing the assembly to move.

The wreckage indicates that the Hi-Loks were never installed in the January 1996 overhaul of the I-beam, which was prompted by the assembly flexing up and down. Original paper documentation was destroyed before being copied into computerized logs. To remove the actuator, the doubler, upper cap and other parts of the Brooklyn Bridge are disassembled. "The actuators have a high frequency of removal," said Col. Guy Vanderman, logistics group commander of the F-117A's 49th FW. "It's tedious and very awkward to reinstall all the fasteners."

Time Compliance Directives were issued in January 1996, requiring inspection of the fastener holes and support tees. For the accident aircraft, the required date was March 1997, the inspection was not accomplished. Post-accident fleet inspection found some loose fasteners but no missing ones. Lockheed Martin and the Air Force are discussing a redesign so the actuator can be removed while leaving the Brooklyn Bridge in place."

The first F-117A delivered with the Brooklyn Bridge assembly was #802 which was accepted on April 6, 1984. Apparently there was an engineering mistake which caused the earlier F-117A's to have "overly flexible wings". The Brooklyn Bridge was designed to patch up that flaw.

In the January 26, 1998 issue of Aviation Week the following letter was published:

"The noncritical inspection to look for and result in correction of loose fasteners is a depot task to be incorporated over four years. It was being tracked correctly by Lockheed Martin Skunk Works and 49th Fighter Wing managers, but the investigation turned up an incorrect compliance date normally used for smaller jobs, which can be done in the field. We plead guilty to minor paperwork confusion.
We also plead guilty to making a Brooklyn Bridge doubler plate that quickly fixed a potential flutter problem but which is tedious and awkward to replace. Funds for redesigning the bridge have been in the queue for some time.
The fasteners that were missing were not removed at the same time as the doubler plate. Their absence was due to a mistake made almost two years ago. The successes of the F-117A are in piloting and maintenance. Everyone in the program is making sure mistakes are not repeated." Signed: Robert M. McGregor, Chief F-117 Engineering and Reliability Specialized Management Directorate, McClellan AFB, Calif."

F-117A #81-793 Crash Footage
CNN footage #11.4 MBAnouncer/Spectators/JetFootage showing crash from airshow crowd
CNN footage #21.3 MBSpectators/JetFootage showing crash and parachute from adjoining lake
CNN footage #31.2 MBNoneFootage showing smoldering wreckage from above
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