IAD99GA013

The police helicopter was performing a police mission less than 500 above ground level when the engine lost power. The pilot was unable to reach a suitable landing area and maintain rotor rpm. The helicopter struck trees and a light pole, landed hard on a road, and slid into a fence. Examination revealed the #2 connecting rod had separated from the crankshaft. A torque check on the remaining connecting rod bolts found all below the minimum specified. A work action (strike) had been in effect at the engine manufacturer at the time of engine assembly, and production continued with management and replacement workers. During assembly the crankshaft had been replaced for an unknown reason. After the crankshaft was replaced, new connecting rods were attached, but not properly tightened. Replacement workers manned the two assembly stations identified as most probable for replacement of the crankshaft and failure to tighten the connecting rod bolts. Although long time employees knew the correct procedures for documentation of a replaced crankshaft, no specific written instructions were available for the replacement employees. The engine failed at 45.7 hours total time.

History of flight

On November 4, 1998, at 1428 Eastern Standard Time, a Schweizer 269C, N2100B, was destroyed when it impacted terrain during a forced landing in Baltimore, Maryland. The certificated commercial pilot/police officer was fatally injured and the aerial observer received serious injuries. The helicopter, owned by U.S. Leaseco Inc., maintained by Helicopter Transport Services, Inc., and operated by the Baltimore Police Department Helicopter Unit, was on an aerial observation flight at the time of the accident. Visual meteorological conditions prevailed, and no flight plan was filed for the public use flight conducted under 14 CFR Part 91.

According to records, the helicopter was flown that morning for 2 1/2 hours. No discrepancies were recorded for that flight. The observer reported the flight departed Martin State Airport about 1310. About 1420, a police ground unit requested assistance from the helicopter flight crew.

According to the aerial observer, the assist consisted of not flying below 500 feet mean sea level, and maintaining an airspeed of about 30 to 40 mph, while watching a vehicle. When released from their assignment, the pilot added power, climbed and turned left. At the same time the helicopter started shaking left and right very hard, and the aerial observer reported that he observed smoke in front of the helicopter. The pilot did not say anything. The helicopter was directly over an alley or small street. The pilot initiated an autorotation.

The helicopter continued to turn to the south, toward a row of houses. The pilot turned right to clear the houses and then back toward the south. The skids struck the tops of trees, and then a light pole, which folded up. The helicopter was coming down fast, which was not normal. The helicopter struck the middle of an east/west street traveling south. It momentarily became airborne as they bounced in front of a moving police car, and continued across the street, accompanied by a massive banging noise.

The helicopter slid through a fence and came to rest on its left side. The aerial observer reported that he was still conscious. Another police officer was at the site within seconds, and called to the pilot who was unconscious. The police officer then tried to remove their seat belts, but could not release them and cut them instead. They were subsequently pulled out of the helicopter.

The aerial observer further added, "When the engine failure occurred, there was no place to go."

A police officer, located about two city blocks west of the suspect vehicle, stated:

"...(I heard) something on the radio. I am not sure if it was a ground unit or Fox (the helicopter). Out of the corner of my eye I observed something, I glanced up and saw (the helicopter) coming down. It appeared that the rotor blade...wasn't spinning normally. It appeared to be slow."

Other witnesses reported hearing a loud pop and saw smoke trailing from the helicopter. A police officer reported that "the helicopter made a sharp hook through two buildings and hit the street approximately 5 feet in front of my car."

A small post crash fire developed behind the occupants, which was extinguished by police officers prior to the arrival of fire trucks.

The accident occurred during the hours of daylight at 39 degrees, 17.14 minutes north latitude, and 76 degrees, 37.87 minutes west longitude.

Personnel information

Pilot

The pilot held a commercial pilot certificate with ratings for airplane single and multi-engine land, rotorcraft-helicopter, and instrument helicopter. He was last issued a second class Federal Aviation Administration (FAA) airman medical certificate on September 29, 1998.

According to the NTSB Pilot/Operator Aircraft Accident Report form, filled out by the Baltimore Police Department, the pilot's total flight experience was 16,000 hours, with 14,000 in make and model. In the preceding 90 days and 30 days, he had flown 200 hours and 70 hours respectively.

According to the pilot's training file, he last received a flight check on March 27, 1998. The checkride included autorotations that were straight in, with turns, from a hover, and with a power recovery. The comment from the check airman was "Good Ride."

Aircraft information

The helicopter was a Schweizer 269C that had been modified with the installation of police radios and an external searchlight. No navigation radios were installed.

The maximum certificated gross weight of the helicopter was 2,050 pounds. A weight and balance for the accident flight was computed by Schweizer Aircraft Company at 1,954 pounds, and the weight at the time of the accident as 1,860 pounds.

Wreckage and impact information

Examination at the accident site revealed ground scarring and debris scattered in a southerly direction for 89 feet. The first contact with a ground object was at the top of a tree estimated to be 40 to 45 feet tall, and located 20 feet south of a dwelling. Thirty feet further along, a 20-foot-tall light pole was laying on the ground. Blue paint-transfer marks, similar in color to the helicopter, were found on the pole. About 17 feet beyond the pole, was a 3-foot-long scrape in the asphalt. Twelve feet beyond the scrape, there were two additional, parallel scrapes, 9 feet long, and 9 feet apart. The helicopter came to rest 21 feet beyond the parallel scrapes, lying on its left side. The landing skids were fragmented, and the tail boom was separated from the structure.

No evidence of a mechanical malfunction was found with the main rotor, tail rotor, drive system, or flight controls. According to a report from Schweizer aircraft:

"...There was minimum chordwise compression of the main rotor blade airfoils...There was flapwise bending of the blue and yellow blades...There was minor impact damage to the tips of the red and blue blades. The red blade had a down bend about mid span and tip impact deformation...Tail rotor drive continuity was established...The tail rotor blades exhibited side impact signatures with damage to the airfoil fiberglass...The tip caps were cracked and separated...All flight controls were verified to have been intact and functional prior to impact...All blades on the [engine] impeller were intact...."

Holes which measured 4 inches on the top, and 2 inches on the bottom, were found on the engine case near the number 2 cylinder. A visual examination through the holes revealed the number 2 connecting rod was not attached to the crankshaft.

The engine was taken to Textron Lycoming for disassembly. After the crankcase was split, the crankshaft was removed with the number 1, 3 and 4 connecting rods attached. Measurements were made of the stretch on the connecting rod bolts, and of the torque needed to tighten the bolts. All measurements taken were less than Textron Lycoming specified in their production documents.

Medical and pathological information

The pilot's toxicological testing report from the FAA Toxicology Accident Research Laboratory, Oklahoma City, Oklahoma was negative for drugs and alcohol.

The pilot's autopsy was conducted by the Medical Examiner's Office, City of Baltimore, Maryland.

Tests and research

The fractured connecting rod bolts from the number 2 connecting rod were examined at the Safety Board Materials Laboratory in Washington, DC. According to their factual report:

"...The fracture face on the [number 2 connecting rod] bolt piece...was typical of a tensile separation with a degree of bending evolved...[On the other bolt] Examination of the fracture face revealed a flat surface with an arced periphery, that was perpendicular to the bolt axis and a final separation lip at 45 degrees. Further examination in a scanning electron microscope (SEM)...revealed the banding confirming a fatigue separation. The fatigue initiation location was within the damaged area...

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