NTSB Factual Report

HISTORY OF FLIGHT

On April 22, 2000, about 1241 Eastern Daylight Time, a Beech N35, N1253Z, was destroyed during an in-flight breakup, and subsequent collision with terrain near Conicville, Virginia. The certificated private pilot and passenger were fatally injured. Visual meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed for the flight that originated at the Caro Municipal Airport, Caro, Michigan, destined for the Newport News/Williamsburg International Airport, Newport News, Virginia. The personal flight was conducted under 14 CFR Part 91.

According to Federal Aviation Administration (FAA) transcripts of communications, the airplane was in cruise flight at 9,000 feet, when the pilot radioed air traffic control (ATC) that he had an electrical failure. The pilot then radioed ATC again and stated that he had experienced a gyro failure. The ATC controller then observed the airplane enter into a high rate of decent on the radar screen.

Review of communications between the pilot and ATC, revealed that the pilot reported a loss of gyro suction at 1623:59.

At 1624:50, the pilot stated, "...I guess my gyro is uh uh going right round and round"

At 1625:07, the pilot stated, "as long as we stay on top we can what's the uh has anybody got any uh broken conditions uh south ah here"

At 1626:33, the controller stated, "five three zulu the closest airport I'm showing with uh a broken layer is charlottesville Shenandoah and petersburg uh are both showing a overcast layer"

At 1626:51, the pilot stated, "uh yeah uh gimme um ah heading to somebody's that broken then that's what I'm gonna have to do"

At 1629:23, the controller stated, "so uh five three zulu you do have your uh gyro back you just wanna go to the closest airport with a broken ceiling is that the way I understand it"

At 1629:31, the pilot stated, "I do not have my artificial horizon my gyro uh I got the compass and the airspeed indicator"

At 1630:03, the pilot stated, "I uh I have to stay on top cause I haven't got my artificial horizon"

For the next 2 minutes, the controller issued heading instructions to the pilot for the Charlottesville Airport, Charlottesville, Virginia.

At 1632:36, the pilot stated, "alright just stay on this heading and uh so till something shows up uh long as I can stay on top I can uh uh keep the darn thing right side up cause I lost my artificial horizon"

At 1632:56, the pilot stated, "what are you showing me for altitude"

The controller replied, "I'm showing you at uh nine thousand eight hundred I don't have any traffic in that area if you can't uh hold an altitude that's fine uh just do the best you can"

At 1633:09, the pilot stated, "try to see what uh what I can rely on here and what I can't take it back to nine uh it's startin to open up here right now"

At 1634:28, the controller stated, "and uh five three zulu I'm showing you level at nine thousand now"

The pilot replied, "I'm trying to hold it at"

At 1634:52, the controller stated, "November uh five three zulu you havin any kind of electrical problems or was it just a failure of that particular uh piece of equipment"

The pilot replied, "looks like it's probably gonna be the gyro or the suction pump cause I've uh I don't have the artificial horizon I do not have directional gyro uh th the gps is working the airspeeds working altimeters working"

At 1635:44, the controller asked the pilot if he could descend to 7,000 feet and stay on top, or if he wanted to stay at 9,000 feet.

At 1636:05, the pilot stated, "right now I'm pre I'm almost I'm in the clouds right now"

The controller then asked if the pilot could climb the airplane, to which the pilot replied, "affirmative." The pilot was then instructed by the controller to climb and maintain 11,000 feet. The controller also declared "an emergency" for the pilot, and for the pilot to utilize any altitude needed to "maintain on top."

At 1639:03, the pilot stated, "...what altitude de you show five three zulu at"

The controller replied, "okay uh your mode c's comin and goin last I saw was nine thousand seven hundred I'm not picking up a mode c right now"

At 1639:17, the pilot stated, "I'm showing myself on an easterly heading all my instruments have gone haywire"

The controller replied, "okay uh I just showed ya at one zero thousand now it just popped up at one zero thousand are you on top now"

The pilot replied, "negative and uh my uh vertical speed is uh going"

At 1639:58, the controller stated, " five three zulu I'm showing you ah one zero thousand four hundred"

The pilot replied, "Washington center my airspeed indicator is going from oh man I'm gonna..."

No further transmissions were received from the airplane.

A witness, who was located about 15 feet from where the main wreckage impacted the ground, stated that he heard an "engine popping noise that became progressively slower." The witness then looked to the sky and noticed an airplane that had "pieces falling from it." The witness then heard at least two loud bangs and decided to run, as the airplane was heading to the ground toward him.

A second witness, who was located about 3/4 of a mile from the accident site, stated that he noticed a plane doing "air tricks," and making sputtering noises. The witness "focused" on the airplane and watched it break into pieces. The witness also recalled hearing three loud booms coming from the direction of the airplane.

The accident occurred during the hours of daylight. The wreckage was located 38 degrees, 49.201 minutes north latitude, 78 degrees 43.579 minutes west longitude, and at an elevation of 1,423 feet.

PILOT INFORMATION

The pilot held a private pilot certificate with a single engine land and instrument ratings. His most recent FAA third class medical was dated July 28, 1998.

Review of the pilot's logbook revealed he had accumulated about 1,554 hours of total flight experience, with 89 hours being conducted under actual instrument conditions. His last recorded entry for flight in actual instrument conditions was on September 7, 1997, which was for 1.3 hours.

The pilot's last endorsement for an instrument competency check was on April 15, 1995.

AIRCRAFT INFORMATION

According to maintenance logbooks, as of July 27, 1999, the airplane had accumulated about 4,589 hours of total time in service and the engine had about 1,524 hours total time in service.

There was no information in the maintenance logbooks regarding the installation of the vacuum pump.

METEOROLOGICAL INFORMATION

The weather reported at Shenandoah Valley Regional Airport, Staunton, Virginia, which was located about 35 miles to the south of the accident site, at 1244 was, winds from 340 degrees at 11 knots, gusts to 17 knots, 10 statute miles of visibility, scattered clouds at 4,400 feet, broken clouds at 8,000 and 10,000 feet.

WRECKAGE INFORMATION

The wreckage was examined at the accident site on April 23, 2000. The main wreckage consisted of the fuselage, engine, and propeller. It came to rest on private property, inverted on top of a power transformer. The power transformer was set in place on top of a concrete pad. The forward section of the fuselage was oriented on a magnetic heading of about 120 degrees.

The control yoke and column was found approximately 600 feet to the northwest of the main wreckage. Approximately 400 feet to the southwest of the main wreckage was the left wing inboard section. Approximately 550 feet to south of the main wreckage was the right wing. Sections of the left-hand elevator were found approximately 2,500 feet and 4,100 feet southwest of the main wreckage. The left and right hand horizontal stabilator and the right hand elevator were not located.

The fuselage was in one complete section, and crushed along its vertical axis. The nose landing gear was in the retracted position. The gear selector handle was in the retract position. Both the left and right wings were separated at their respective forward attach points. About 18 inches of the left aft spar and 5 inches of the right aft spar remained attached to the fuselage. All fractures displayed 45-degree shear planes. The left side of the carry-through spar was not deformed. Examination of the elevator control surface stops did not reveal evidence of damage.

The inboard section of the right wing displayed damage consistent with impact, and was severely deformed. The leading edge on the section also exhibited damage consistent with impact. The right main landing gear remained attached to the wing, and was extended. The wing fuel tank was compromised.

The inboard section of the left wing also displayed damage consistent with impact, and was severely deformed. Along the leading edge was a 12 inch wide by 9 inch deep dent, which displayed metal scratching consistent with aircraft skin rivets and white paint transfer marks. The left main landing gear was in the retracted position. The wing fuel tank was compromised.

Examination of the engine revealed that all four engine-mounting brackets were broken. The oil sump was fractured and about 5 quarts of oil was observed on the ground under the engine. When the wreckage was turned 180 degrees, about 2 additional quarts of oil drained from the engine. A film of oil was observed on the bottom skin of the fuselage. The film extended from the exhaust pipes onto the engine cowl covers then rearward along the remaining length of the fuselage.

When the engine's crankshaft was rotated, compression was obtained on all six cylinders, the accessory gear drive section rotated, and valve train continuity was confirmed. All spark plugs were removed, except for the number 1 cylinder bottom spark plug. The removed spark plugs electrodes were intact, bent, and light gray in color. The left and right magnetos were destroyed. The left and right mufflers were broken from the exhaust system, and did not reveal any abnormal wear.

The fuel manifold valve was damaged, and when removed from the engine, an odor of fuel was noted. The throttle body was broken from its mounts. The butterfly valve was in the full open position. The linkages from the throttle and mixture controls in the cockpit were broken from the throttle body. The fuel selector valve was found in the right tank position. The fuel selector valve sump contained about 1 cup of fuel similar in color and odor to aviation gasoline.

The propeller, which remained attached to the engine, was not damaged and was found in the low pitch position. Damage to the propeller spinner cap was limited to the upper half.

The alternator belt was found loose about the alternator housing and the pulley wheel attached to the engine accessory drive case.

Examination of the vacuum pump, which was removed from the engine, revealed the drive shaft had sheared.

MEDICAL AND PATHOLOGICAL INFORMATION

The Commonwealth of Virginia, Department of Health, Office of the Chief Medical Examiner, Fairfax, Virginia, performed an autopsy on the pilot, on April 24, 2000.

The FAA Toxicology and Accident Research Laboratory, Oklahoma City, Oklahoma conducted toxicological testing on the pilot.

TEST AND RESEARCH

The vacuum pump, attitude indicator gyro, directional gyro, and electric turn coordinator gyro, were retained and sent to the Safety Board's Materials Laboratory for examination.

According to the Metallurgist factual report, no evidence of rotational scoring was observed on either the inside housing or the rotor of the attitude indicator gyro or directional gyro. No evidence of rotational scoring was also observed on the surface of the electric turn coordinator.

Examination of the vacuum pump drive shaft with a binocular microscope revealed circular features consistent with torsional overstress. Higher magnification with a scanning electron microscope revealed elongated dimples, typical features of torsional overstress separations, on the fracture surface of the vacuum pump drive shaft. Directional orientation of the dimples were consistent with the shaft continuing its normal turn at the engine input end of the shaft, with the vacuum pump end of the shaft remaining stationary.

Disassembly of the vacuum pump revealed the rotor to be intact, but containing circumferential rubbing marks. After disassembly of the vanes from the rotor, the rotor could only be rotated very small amounts relative to the end plate. Examination of the pump vanes revealed two intact vanes, and two broken vanes.

ADDITIONAL INFORMATION

The airplane was released on April 25, 2000, to a representative of the owner's insurance company.

NTSB Probable Cause

The pilot's in-flight decision to continue flight into IMC conditions, and his failure to maintain control of the airplane. Factors related to the accident were the failure of the vacuum pump and the pilot's lack of recent instrument time.