FTW01FA015
FTW01FA015

HISTORY OF FLIGHT

On October 30, 2000, at 1824 central standard time, a Beech BE-76 twin-engine airplane (also known as a Dutchess), N23823, was destroyed when it impacted terrain during a go-around near the Richard Lloyd Jones Jr. Airport near Tulsa, Oklahoma. The airplane was registered to and operated by Christiansen Aviation, Inc., of Tulsa, Oklahoma. The flight instructor and the pilot receiving instruction were fatally injured. Night visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 instructional flight. The local flight departed the Richard Lloyd Jones Jr. Airport approximately 1530.

Air traffic control (ATC) personnel reported that the pilot radioed Tulsa Approach Control and stated that they were 4 miles north of the Okmulgee Airport (approximately 18 miles south of Richard Lloyd Jones Jr. Airport, RVS), and they had an engine on fire. At that time, the pilot requested a straight in landing on runway 1L at RVS. The ATC personnel asked the pilot to describe the problem again and the pilot reported an engine fire. The approach controller asked the pilot to indicate how many people were on board, how much fuel was on board, and which engine was on fire, to which the pilot responded 2 people, 2 hours of fuel, and the right engine. According to RVS tower personnel, they observed the airplane approach "fast," and saw smoke coming from the right engine. One controller reported seeing flames coming from the right engine. The pilot reported to the control tower that "the gear [was] not operating" and that he had to go-around. He added that "one of the lights [was] not coming on." The controller reported to the pilot that the landing gear appeared to be extended and cleared him to land on either runway at his discretion. The pilot indicated that he was going to attempt to land on runway 19R. The controllers stated that the airplane initiated a climb then started to roll over to the right and pitch nose down. The airplane impacted the ground and a fire erupted upon impact.

Numerous witnesses, located at various areas on the airport, reported that the airplane approached to runway 1L with a tailwind, and was "very fast on approach." The witnesses then heard an application of engine power, and the airplane pitched nose up and started to climb. The witnesses stated that the airplane then slowed and rolled right inverted and pitched nose down until it impacted the ground. Some of the witnesses stated that the landing gear appeared to be in the extended position.

PERSONNEL INFORMATION

The flight instructor obtained his multiengine instructor rating on May 7, 2000. He was issued a first class medical certificate on July 11, 2000, with the limitation, "must wear corrective lenses." A review of the flight instructor's logbooks revealed that he had accumulated approximately 1,398 total flight hours, 473 total multiengine airplane hours, and 877 hours of instruction given.

The pilot receiving instruction held a German-issued private pilot certificate and received an FAA-issued instrument airplane rating on March 22, 1995. The pilot obtained an FAA-issued airplane single engine sea rating on May 3, 2000. According to the application for that rating, the pilot had accumulated 390 hours of flight time. A review of the pilot's logbook revealed that the pilot was receiving flight training for a commercial certificate with an airplane multiengine land rating at the time of the accident. The pilot had passed the commercial written test on September 18, 2000. Review of the pilot and instructor logbooks revealed that the pilot had received 26.3 hours of multiengine instruction prior to the accident flight, of which 21.1 hours were in the accident airplane. The pilot had practiced "engine out & recovery" procedures during his most recent flight on October 28, 2000.

AIRCRAFT INFORMATION

The twin-engine airplane was manufactured in 1978 by Beechcraft Corporation (now known as Raytheon Aircraft Company). Installed on the aircraft were two Lycoming O-360-A1G6D engines. A review of the aircraft maintenance records revealed that the airplane underwent its last annual inspection on September 29, 2000, at an aircraft total time of 5,827.79 hours. At the time of the last annual, the right engine had accumulated 5,745.19 total hours and 3,784.42 hours since its last overhaul, and the left engine had accumulated 5,827.79 hours and 3,829.39 hours since its last overhaul. At the time of the accident, the airplane had accumulated a total of 5,921.33 hours. There was no evidence of open discrepancies in the aircraft flight logs and the aircraft maintenance records.

METEOROLOGICAL INFORMATION

At 1825, the RVS weather observation facility reported the wind from 150 degrees at 8 knots, clear sky, visibility 10 statute miles, temperature 73 degrees Fahrenheit, dew point 66 degrees Fahrenheit, and an altimeter setting of 30.01 inches of Mercury.

According to the U.S. Naval Observatory, sunset at Tulsa on October 30, 2000, occurred at 1730, and the end of civil twilight occurred at 1756.

WRECKAGE AND IMPACT INFORMATION

The airplane came to rest intact within one mile northeast of the approach end of runway 19L in open and uneven terrain, adjacent to a 15-foot ditch. The airplane was upright and facing a 094-degree magnetic heading. The cockpit area, left side of the vertical stabilizer and horizontal stabilizer, and left wing sustained fire damage. Sections of the right wing also sustained fire damage. The left wing's leading edge was accordion crushed aft and its spar was bent aft. The right wing sustained upward compression damage from the bottom side.

The cockpit's engine controls for both engines were found in the full forward position and the landing gear handle was in the extended position. The vertical speed indicator was depicting a 1,250 foot/minute descent rate. The manifold pressure gauge depicted the left engine at 25 inches and the right engine at 29 inches. The left engine's tachometer was indicating 2,500 rpm and the right engine's tachometer was indicating 400 rpm.

Flight control continuity was confirmed from the cockpit area to the respective flight control surfaces. Both control yokes were found separated from their control columns. The airplane fuselage was lifted and the landing gear were found extended and bent aft. The landing gear indication lights were removed for further examination. The flap jack screw was extended 6 inches, which corresponds to a flaps retracted position.

The left engine's propeller was separated from the engine's crankshaft aft of the propeller hub. Both blades displayed leading edge rubbing and gouges.

The right engine propeller remained attached to the engine crankshaft. One blade was positioned in the 12 o'clock position, did not appear to be feathered, and did not display any leading edge damage or blade twisting. The other blade was found in the 6 o'clock position, did not appear to be feathered, was bent 90 degrees aft at the root, and displayed no leading edge damage.

The right engine cowling displayed dark black soot that streaked aft, initiating at the nose of the cowling and its firewall attachment areas. After removing the right engine cowling, it was noted that the right engine compartment was coated in dark black soot. Examination of the engine compartment revealed that the oil line connecting the oil cooler and oil filter adapter on the accessory case was separated at the oil filter adapter's fitting. The oil line and fitting were removed and sent to the NTSB Materials Laboratory in Washington, D.C., for further examination.

The throttle, mixture, and propeller controls on each engine were found in the mid power range, mid mixture range, and high RPM setting respectively. The fuel selectors for the left and right engines were found in the on and off position, respectively.

The engines were removed from their respective firewalls and mounts and taken to an airport maintenance facility. The right engine's (serial number L-110-71A) crankshaft was rotated by manually rotating the propeller. Crankshaft continuity was confirmed to the accessory case, and rocker arm movement and thumb compression were noted on all 4 cylinders. The magneto and ignition harness sustained fire damage, which precluded a functional test. Crankshaft continuity and thumb compression was confirmed on all 4 cylinders of the left engine (serial number L-24061-36A). The wreckage was relocated to Air Salvage of Dallas for further examination.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed on the flight instructor at the Office of the Chief Medical Examiner in Tulsa, Oklahoma. There was no evidence of any pre-existing conditions that would have contributed to the accident. A toxicology test on the flight instructor for carbon monoxide, cyanide, ethanol, and drugs revealed the following results: An unquantified amount of azacyclonol detected in the blood and urine, an unquantified amount of ephedrine detected in the urine, and an unquantified amount of phenylpropanolamine detected in the urine. According to the Toxicology and Accident Research Laboratory in Oklahoma City, Oklahoma, "Azacyclonol is a metabolite of Allegra. Phenylpropanolamine is a component of weight loss diet preparations and some cold medications. These findings are not considered to be of significance in contributing to the cause of the accident."

TESTS AND RESEARCH

On November 1, 2000, the NTSB IIC and a representative from the aircraft manufacturer examined the left and right engines, and the right engine firewall at Air Salvage of Dallas. The propeller governor oil line, which is routed from the propeller governor on the accessory case to the forward right half of the crankcase (aft of the propeller flange), was separated at its governor end fitting. The attachment fitting was found fractured and displayed a 45 degree shear lip, which is consistent with an overload failure. The governor line was removed and pressurized with 80 pounds of air pressure; no leaks were noted.

On November 9, 2000, the NTSB Materials Laboratory examined the oil line and fitting that was found separated at the accident site. The B-nut displayed no evidence of cross threading and the thread damage was consistent with overload failure.

On January 18, 2001, the NTSB IIC, along with representatives from the aircraft, engine, and propeller manufacturers, examined the right engine, firewall, and propeller. Examination of the right engine and firewall revealed that the engine driven fuel pump inlet line was void of any remnants of a fire sleeve. Examination of photographs taken at the accident site and subsequent examinations revealed that all of the fuel and oil lines in the engine compartment displayed burnt remnants of fire sleeves with the exception of the fuel pump inlet line. Closer examination of the line revealed a crack in the socket adjacent to the firewall attachment B-nut. The engine driven fuel pump inlet line was removed and sent the NTSB Materials Laboratory for further examination. The engine driven fuel pump was removed from the engine, disassembled, and examined. The fuel pump's internal components were found in place and intact with the exception of the seals, which were burnt and charred.

The right propeller (Hartzell HC-M2YR-2CLEUF, serial number FB1038) and spinner assembly were examined. This propeller model is a 2-bladed single acting, hydraulically operated constant speed, full feathering type. Oil pressure from the propeller governor is used to move the blades to the low pitch (high RPM) blade settings, and an air charge, counterweights, and a feathering spring are used to move the blades to a high pitch (low RPM) blade setting. The propeller incorporates a start lock mechanism that holds the blades in a low pitch position during engine start up. The right propeller rotated counter-clockwise as viewed from the rear. The examination of the right propeller revealed that the low pitch stop/air valve was missing. Black soot was noted on the aft side of the blades and the spinner bulkhead. Black soot was also noted on both the front and rear sides of the starter ring gear; however the alternator belt groove displayed a soot-free area around its circumference where the belt would have been statically positioned. The spinner dome was dented on one side and displayed impact damage on its nose. The dome displayed an impact mark, from the inside-out, similar in shape as the counterweight, which correlated with a low pitch blade angle setting. The propeller cylinder displayed two dents which correlated with the counterweight positions. The propeller cylinder and propeller piston change rod were cut in half to facilitate disassembly. The feathering spring, guides, and stops, and the start locks were intact and unremarkable. Examination of the preload plates displayed impact marks, which correlated with a low pitch blade angle at the time of impact, and there was a notable absence of witness marks in the area of the high pitch or feather position. No anomalies were noted that would have prevented the operation of the propeller.

The landing gear indication lights were examined under a microscope by the NTSB IIC. All of the indication lights displayed filament stretch with the exception of the transit light and the right main landing gear indication light. The right main landing gear's indication light filament was found separated.

On May 30, 2001, the NTSB Materials Laboratory examined the engine driven fuel pump's inlet line using optical microscopy. The fracture surface in the socket was irregular and rough with a granular appearance, which are features consistent with overstress fracture at high temperature. No evidence of a preexisting crack was observed.

ADDITIONAL INFORMATION

The Dutchess 76 Pilot Operating Handbook (POH) listed the emergency procedures for an ENGINE FIRE IN FLIGHT as follows:

"Shut down the affected engine according to the following procedure and land immediately. Follow the applicable single-engine procedures in this section. 1. Fuel Selector - OFF 2. Mixture Control - IDLE CUT-OFF 3. Propeller - FEATHER 4. Aux Fuel Pump - OFF 5. Magneto/Start Switch - OFF 6. Alternator Switch - OFF"

The POH continued to describe the emergency procedures for a ONE-ENGINE INOPERATIVE GO-AROUND as follows:

"WARNING Level flight may not be possible for certain combinations of weight, temperature and altitude. In any event, DO NOT attempt a one-engine inoperative go-around after flaps have been fully extended. 1. Power - MAXIMUM ALLOWABLE 2. Landing Gear - UP 3. Wing Flaps - UP 4. Airspeed - MAINTAIN 85 KNOTS MINIMUM"

The aircraft wreckage was released to the owner's representative on June 8, 2001.

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