Accident Details
Probable Cause and Findings
The failure of the pilot and company maintenance personnel during preflight and periodic inspections to identify the signs of fretting and looseness in the "red" main rotor blade pitch change horn to main rotor blade grip attachment, resulting in the helicopter continuing in service with a loose pitch change horn, separation of the pitch change horn from the blade grip, and inflight breakup of the helicopter due to the main rotor striking the tailboom. Contributing to the accident was the pilot's failure to respond to increased vibration in the main rotor system and land immediately.
Aircraft Information
Registered Owner (Historical)
Analysis
History of the Flight
On November 27, 1999, about 1445 central standard time, a Bell 212, N8144M, registered to Houston Helicopters, Inc., crashed near Philadelphia, Mississippi, while on a Title 14 CFR Part 91 positioning flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The helicopter was destroyed and the airline transport-rated pilot and one passenger were fatally injured. The flight last departed Tuscaloosa, Alabama, the same day, about 1408.
The helicopter was being positioned from Virginia, to Pearland, Texas, the home base for the helicopter operator. Transcript of communications from the FAA Air Traffic Control Tower, Tuscaloosa, Alabama, show the flight arrived at Tuscaloosa at 1329. The lineman at Dixie Air, Inc., Tuscaloosa, Alabama, who fueled the helicopter, stated he talked with the pilot and passenger when they arrived. They stated they were flying to Texas, and had been flying since early that morning. They stated that sometime that morning, the greenhouse window above the pilot had broken. They then requested that the fuel tanks be completely topped off with Jet-A fuel. The lineman stated that when he went to the helicopter to fuel it, he observed that the greenhouse window was cracked lengthwise. Transcripts show that at 1408, the pilot requested and was given a west departure from Tuscaloosa. No further contact with air traffic control facilities were made after this. (See transcript of communications and witness statement).
The transcript of communications recorded on the cockpit voice recorder showed that about 29 minutes before the accident, the passenger stated to the pilot "I think if I hadn't-a broke that off we wouldn't had any greenhouse by the time we got home". About 18 minutes before the accident, the passenger stated to the pilot "boy those catfish are going crazy down there aren't they". The pilot respond "yep", "must have been the vibrations from the helicopter". About 2 minutes later the passenger and pilot discuss sighting deer in a field. About 1 minute 30 seconds before the accident, the pilot asked the passenger "has this vertical just gotten in here or has it been here for a while?" The passenger replied "we haven't had any verticals at all." The pilot replied, "we do now." The passenger replied, "yeah well it started right after we left back there. I think it maybe ah that's why I was thinking it was the air." About 20 seconds later, the passenger stated that another person had tracked the helicopter's blades before they left and that he was commenting on how smooth it was. About 40 seconds later the pilot stated "this stuff is getting worse." The recording then ended. (See NTSB Cockpit Voice Recorder Factual Report of Group Chairman).
Witnesses in the area of the accident site stated that they observed the helicopter flying from east to west, just above the treetops. The helicopter began rolling back and forth. They then observed the main rotor blades contact the tail area, and the aft tail boom and tail rotor separate. Shortly after this, the main rotor separated and the helicopter descended and crashed to the ground. A fire erupted during ground impact. Witnesses did not observe any smoke come from the helicopter prior to the accident. (See Witness Group Chairman Factual Report).
Personnel Information
The pilot held a FAA airline transport pilot certificate with a helicopter rotorcraft rating, last issued on March 5, 1984. The pilot held a FAA second-class medical certificate, issued on December 1, 1998, with the limitation that holder shall wear lenses to correct for distant vision and possess glasses that correct for near vision. The pilot was hired by Houston Helicopters, Inc., in March 1999, and after attending ground training, received flight checks to act as pilot in command in the Bell 212, Bell 206, and Sikorsky S-76 helicopters. The Bell 212 flight check was conducted on March 27, 1999. At the time the pilot was hired, he reported he had accumulated 11,019 total flight hours, all in helicopters. He reported he had 2,356 total flight hours in the Bell 212. (See pilot records).
The passenger was employed by the helicopter operator as a mechanic. He held a FAA airframe and powerplant mechanic certificate, last issued on February 26, 1980. The passenger also held a FAA private pilot certificate with a airplane single engine land rating, issued on May 5, 1978.
Aircraft Information
The accident helicopter was a Bell Helicopter Textron Model 212, serial no. 30706, which was manufactured in May 1975. The helicopter was equipped with a Pratt and Whitney Canada PT6-3 engine, rated at 1,800 shaft horsepower, consisting of two 900 shaft horsepower power sections and a reduction gear box.
The helicopter received a 100-hour and annual inspection on April 12, 1999, at aircraft total time 11,243.7. The helicopter received a 25 hour and 50 hour inspection on September 23, 1999, at aircraft total time 11,288.7. On November 5, 1999, the helicopter received a daily and preflight inspection, at aircraft total time 11,302.2. The following discrepancies and corrective actions were noted in the records for the daily and preflight inspection:
"Check M/R servo alignment" [action] "Realigned lateral servos"
"Track and Balance M/R [action] "Performed track & Bal. Check & adjust"
"adjust autorotation RPM" [action] "adjusted auto RPM per M&M"
The "Next Inspection Due, 100 Hr. A B [was entered as] 11,343.7" hours.
The helicopter operator stated that the records for the helicopter were retained on the helicopter after this inspection and were destroyed in the accident. They stated the helicopter would have received a daily inspection by a mechanic each morning. They estimated the helicopter flew about 19 flight hours from the time of this daily and preflight inspection on November 5, 1999, until the time of the accident.
Aircraft records show the "red" main rotor blade grip, part number 204-011-121-9, serial number GD-9312-6, was removed from main rotor hub serial number ADA-08684, in July 1985, after accumulating 4,334.1 total flight hours. The grip was sent to Bell Helicopter Textron by Houston Helicopters, Inc., at this time for overhaul. The grip was then placed in storage and was returned to Bell Helicopter Textron in April 1992 for installation of Rosan fittings in the pitch change horn mounting holes. The Rosan fittings had been left out during the 1985 overhaul at Bell Helicopter Textron. The "red" blade grip was installed on main rotor hub serial number FB-71829 in January 1993, at hub total time 2,500.0 hours and grip total time 4334.1. The hub assembly, including the "red" grip was installed on another helicopter. In February 1994, after 17.5 hours of operation, the hub was removed due to an overspeed occurrence and again overhauled. The "red" grip was inspected for overspeed at this time. In June 1995, the hub was removed for compliance with a service bulletin. On March 25, 1996, the main rotor hub and "red" blade grip was installed on the accident helicopter, N8144M, at helicopter total time 11,050.2. On March 25, 1998, the hub was removed for blade retention strap replacement and then reinstalled on N8144M, on April 3, 1998. At the time of the accident, the "red" grip had accumulated 162.2 flight hours since the March 1998 removal and reinstallation of the main rotor hub, 556.5 flight hours since overhaul in 1985, and 4,890.6 total flight hours since new.
The "red" main rotor blade pitch change horn, part number 204-011-120-005, serial number HT-834, was removed from service in 1985, after accumulating 1,634.9 total flight hours. On January 12, 1993, the horn was installed on main rotor hub serial number FB-71829. At the time of the accident the "red" pitch change horn had accumulated 2,191.4 total flight hours. The horn has a life limit of 3,000 total flight hours.
Meteorological Information
The Key Field Airport, Meridian, Mississippi, 1453 surface weather observation was, sky clear, visibility 10 miles, temperature 19 degrees centigrade, dew point temperature minus 1 degree centigrade, wind from 240 degrees at 3 knots, altimeter 30.16 inches hg. Key Field is located 30 nm southeast of the accident site.
A review of the weather in the area of the accident was performed by the NTSB, Operational Factors Division, Washington, D.C. The review showed that the winds in the area of the accident were light and variable and that the accident helicopter did not encounter any turbulence. (See NTSB, Operation Factors Division Report).
Communications
The pilot was not in radio contact with any FAA Air Traffic Control facility at the time of the accident. The transcript of communications recorded on the cockpit voice recorder showed that the pilot had the radio frequency for the FAA Jackson Approach Control, Jackson, Mississippi, set in the radio. Transmissions from flights approaching Jackson were recorded. One of these flights was Delta Airlines flight 1411. The last transmission recorded from Delta 1411 was about 11 minutes before the accident, when the pilot responded to his clearance to land on runway 6 left at Jackson International Airport.
The NTSB requested from the FAA Jackson Approach Control, a transcript of communications for the approach frequency around the time of the accident. When the transcript was received, it was determined the wrong time frame had been transcribed. When the approach control personnel went back to transcribe the correct time frame, they learned the recording tape had been reused and the recording was no longer available. Delta Airlines reported to the NTSB that flight 1411 arrived at the gate at Jackson International Airport about 1440.
Flight Recorders
The helicopter was equipped with a Universal Avionics CVR30 solid-state cockpit voice recorder (CVR). The CVR was recovered from the accident scene and taken to the NTSB Vehicle Recorders Laboratory, Wa...
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# MIA00FA030