NTSB Factual Report

HISTORY OF THE FLIGHT

On June 15, 1994, at 0805 central daylight time, a Bell BH 47G2, N4992G, piloted by the rotorcraft pilot/registered owner, was destroyed when it impacted terrain in a wooded area after a loss of engine power during cruise flight. The two rotorcraft pilots on board the helicopter received fatal injuries. Visual meteorological conditions prevailed for the flight, no flight plan was filed. The flight operated under 14 CFR Part 91, and originated from the helicopter's home base in Carbondale, Illinois, approximately 0730. The intended destination was Chesterfield, Missouri.

The pilot-in-command (PIC) and second pilot were en route to Metropolitan Helicopter, Inc. in Chesterfield, Missouri, to receive dual instruction in the helicopter. The Chief Pilot for Metropolitan Helicopter stated the PIC "...wanted everything...to be the very best, including himself... ." To that end, the PIC had scheduled refresher training for himself, and transition training (R-22 to Bell 47G2) for the second pilot the morning of the accident. The Chief Pilot stated both pilots had received flight training for helicopter certificates through his company. He described the pilots as "...good students...conscientious, very safety conscious... ." He also stated the pilots were well practiced at autorotations.

Records indicate at 0715 the morning of the accident, the pilots purchased 15 gallons of 100LL aviation fuel to top off the fuel tanks before their departure from Carbondale. Personnel at Southern Illinois Airport in Carbondale reported the PIC was meticulous about caring for his helicopter. They stated he was in the habit of refuelling his helicopter himself, and they observed while he did so the morning of the accident. Airport personnel estimated the helicopter departed about 0730.

Witnesses near Baldwin, Illinois, stated about 0805 on the morning of the accident, they observed the helicopter fly overhead at a low (estimated 200 feet above treetops) altitude. They reported they heard the helicopter engine sputter or backfire, then go quiet, before the helicopter pitched down and descended into a wooded area. Several witnesses reported when the engine sputtered, they saw something like smoke, haze, or condensation of some sort come from the back of the helicopter.

The local residents reported the downed helicopter to local authorities at 0813, and a search was initiated. After several hours, the unsuccessful official search was discontinued. Local farmers continued to look for the helicopter on their own, and eventually located the helicopter in a dried creek bed in a wooded area about 1645.

CREW INFORMATION

The commercial/instrument/flight instructor rated PIC held certificate number 344342329, with airplane single and multiengine land and rotorcraft/helicopter ratings. He started flying airplanes in 1990, and received his private pilot/airplane certificate in February, 1991. He received his private pilot/helicopter rating in January, 1993, his commercial pilot/helicopter rating in March, 1993, and his flight instructor/helicopter certificate in July, 1993. At the time of the accident, the PIC had an estimated 750 hours total flight time, including 285 hours in rotorcraft/helicopter, and 92 hours in the accident make and model. The PIC reportedly occupied the right seat at the time of the accident.

The commercial/instrument/flight instructor rated second pilot held certificate number 2052771, with airplane single and multiengine land and rotorcraft/helicopter ratings. He started flying fixed wing airplanes in 1969, and obtained his private pilot/airplane rating in October, 1970, his commercial pilot/airplane rating in December, 1991, and his flight instructor/airplane certificate in August, 1992. He received his private pilot/helicopter rating in March, 1993, his commercial pilot/helicopter rating in May, 1993, and his flight instructor/helicopter certificate in October, 1993. At the time of the accident, the second pilot had an estimated 506 hours total flight time, including 139 hours in rotorcraft/helicopter, and 7 hours in the accident make and model. The second pilot reportedly occupied the left seat at the time of the accident.

The PIC held a Second Class Medical Certificate, issued March 21, 1994, with the limitation: "Holder shall possess correcting glasses for near vision while exercising the privileges of his airman certificate." The second pilot held a Second Class Medical Certificate, issued September 15, 1993, with the limitation: "Holder shall wear correcting lenses while exercising the privileges of his airman certificate."

AIRCRAFT INFORMATION

Maintenance records indicate the helicopter (airframe) was operated about 8,198 hours since its manufacture date of January 26, 1960. The most recent airframe maintenance logbook entry was dated June 2, 1994, at a total airframe time of 8,183.1 hours, and stated: "Greased airframe per HMI, replaced GE 1683 tail lite bulb, complied with AD 74-08-02, serviced both (2) batteries."

The engine had 1,194 hours total time in service, but zero time since major overhaul (TSMOH), when it was installed on the airframe at the most recent annual inspection, on October 27, 1993. The helicopter had operated about 84 hours since that date. The most recent engine logbook entry stated: "Drained and added 10 quarts fresh Aeroshell 100 mineral oil, cleaned oil screen, resafetied #2 and #4 engine LH cooling panel bolts, complied with AD-62-23-02." The entry was dated May 7, 1994.

The helicopter has a useable fuel capacity of 41 gallons, and was reportedly topped off prior to the accident flight. The helicopter manuals indicate on a standard day, the helicopter should have a range of 176 nautical miles (NM), or 3 hours and 18 minutes. The helicopter accident occurred about 37 NM (and 35 minutes) from the departure airport. There was no evidence of useable fuel in the helicopter, and no apparent spilled fuel at the accident site.

WRECKAGE/IMPACT INFORMATION

Witnesses stated the helicopter engine sputtered, then quit completely, before the helicopter disappeared from sight behind trees. After many hours of search, the helicopter wreckage was located in a dried creek bed within a stand of 70 to 80 foot tall trees. The winding creek bed was 12 to 15 feet wide and about 6 feet deep near the accident site. The helicopter impacted trees and the creek bed embankment in a steep nose down attitude, with slight right bank. There was evidence of impact damage to a 75 foot tall tree located 31 feet northeast of the point where the helicopter wreckage impacted.

The main helicopter wreckage came to rest aligned on an approximate heading of 220 degrees. All helicopter debris was located within 85 feet of the main wreckage. The debris located furthest from the main wreckage were pieces of the main rotor blades. Sections of main rotor blade were discovered in many directions from the main wreckage (see wreckage diagram.)

The main cabin structure was crushed and the bubble window shattered on impact. The seat structure was crushed and the firewall was bent forward, contacting the seat. The skid support legs were fractured, and skid tubes separated from the airframe. Both main rotor blades were heavily damaged and one was broken into many pieces during the accident sequence. All main rotor blade pieces were recovered. The tail boom tubing was bent and buckled, but still attached to the main structure. Oil preservative was observed dripping from fractured tubes. The 90 degree gear box, stabilizer, and both tail rotor blades were separated and impact damaged.

The two saddle type fuel tanks were separated from the airframe and were ruptured. One news helicopter pilot reported when he arrived he saw a small pool (3" around, and 1" deep) of liquid under one fuel tank. He indicated the liquid appeared to be fuel. There was no other evidence of fuel spilled at the accident site. First responders reported there was no smell of fuel when they located the wreckage. There was no sign of useable fuel in the fuel tanks or fuel lines.

The helicopter was recovered from the accident site, and moved to a local towing facility yard for further examination. Examination of the airframe confirmed flight control continuity. Examination of the engine and its accessories revealed there was no evidence of rotational damage to the engine cooling fan or cage. The engine rotated smoothly from the hydraulic pump drive, and compression and continuity were confirmed. The magnetos rotated freely, and the left magneto sparked. The right magneto was damaged and did not produce spark.

The carburetor was partially separated from the mount, and impact damaged. Approximately 1 ounce of fuel was drained from the carburetor bowl. There was no evidence of fuel in the fuel lines or the fuel filter. Examination of the fuel filter revealed the bowl was loose to touch, and there was no evidence of safety wire on the lock screw. According to the helicopter maintenance manual, the fuel filter bowl lock screw is required to be safety wired.

MEDICAL/PATHOLOGICAL INFORMATION

On June 16, 1994, autopsy examinations were performed on both pilots at St. Clement's Hospital in Red Bud, Illinois. The autopsy reports indicated no evidence of preimpact anomaly in either pilot. Autopsy reports RACO-16-94 and RACO-17-94 are available through Neil V. Birchler of the Randolph County Coroner's Office, Randolph County Courthouse, Chester, Illinois, 62233, (618) 826-5000.

Toxicological examinations were also performed on both pilots. Examination of the PIC revealed evidence of ethanol in blood and urine (14.00 mg/dl and 30.00 mg/dl, respectively) and acetaldehyde in blood (1.00 mg/dl.) FAA medical personnel did not consider these findings significant to the accident. No other anomalies were noted in the PIC. The second pilot's examination revealed no evidence of toxicological anomaly.

NTSB Probable Cause

The inadequate maintenance (inspection of aircraft) by maintenance personnel, which resulted in a loss of engine power due to fuel exhaustion. Related factors are the unsafetied fuel filter, and low altitude at which the helicopter operated.