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On October 30, 1999, about 2210 eastern daylight time, a Cessna T310R, N4XZ, registered to Southern Aerial Photography Inc., impacted with the water about 10 miles north of Key West, Florida. Visual meteorological conditions prevailed at the time, and an IFR flight plan was filed for the 14 CFR Part 91 personal flight. The airplane sunk in about 20 feet of water, and was destroyed. The commercial-rated pilot and three passengers received fatal injuries. The flight had departed from the Key West, Florida Airport, en route to Fort Lauderdale, Florida, at 2200.
According to air traffic control (ATC) at Miami Center, at the time the airplane departed from Key West, the ATC tower was closed. The pilot made radio contact with Miami Center and was advised that he was in radar contact leaving an altitude of 5,500 feet msl. The controller at Miami Center observed the airplane in a turn and losing altitude. The controller radioed the pilot and asked if he needed assistance. The pilot answered "standby." Radar and radio contact were lost at 2210.
About 0200, a United States Coast Guard aircraft found debris in the water at 081.46 West and 24.41 North.
It was reported, by line personnel at Key West, that the airplane arrived about noon on October 30, 1999, and was topped off with fuel.
Radar data showed that the flight was about to intersect the V157 airway, and was at an altitude of 5,800 feet. The flight started drifting left of the airway and climbed from 5,800 feet to 7,400 feet, reaching 7,400 feet in 2 minutes and 01 second. The airplane turned about 180 degrees to the left, and descended 1,500 feet to an altitude of 5,900 feet, in 47 seconds. The flight continued to descend 4,200 feet, from 5,900 feet to 1,700 feet, in 2 minutes and 36 seconds. The last radar return was at 2209:40, and no altitude was recorded. In addition, the transcript of radio communication indicated that between 2203:04 and 2203:41, the pilot was receiving his IFR clearance. At 2203:41, the pilot read back the clearance incorrectly.
The calculated rate of climb from 5,800 feet to 7,400 feet was about 995 feet per minute. The calculated rate of descent from 7,400 feet to 5,900 feet was about 1,915 feet per minute. The calculated rate of descent from 5,900 feet to 1,700 feet was about 1,615 feet per minute.
Due to the ocean conditions and high winds the search for the airplane and victims took several weeks. The airplane was not recovered from the ocean until November 15-16, 1999.
The accident occurred during the hours of darkness about 24 degrees, 41 minutes north, and 081 degrees, 46 minutes west.
The pilot's personal logbook listing his flight hours was not recovered. Based on his last application for insurance, dated April 20, 1999, it was estimated that the pilot had about 1,207 hours of total flight time in all aircraft, and 36 hours in this make and model airplane, at the time of the application. In addition, at the time of the application the pilot listed 48 hours of night flight time.
The airplane's maintenance records showed that the last entry dated October 28, 1999, was, "Lubed waste gates, inspected left and right exhaust...CAV-AIR Inc."
The weather for Key West, Florida, about 10 miles south of the crash site at 2153 was; wind 040 at 9 knots; visibility 10 sm, lowest ceiling 15,000 broken; temperature 79 degrees F; dew point 73 degrees F; altimeter 30.08 in Hg.
The reported condition of the ocean, according to the United States Coast Guard station, Key West, Florida, about the time of the accident was; ocean swells (6 to 8 feet), and the winds were from the northeast at 15 to 20 knots.
Computerized sun and moon information revealed that about the time of the accident the altitude of the sun was minus 46.2 degrees below the horizon. The altitude of the moon was minus 28.5 degrees below the horizon. (See sun and moon information, an attachment to this report).
MEDICAL AND PATHOLOGICAL INFORMATION
Dr. Robert J. Nelms performed an autopsy on the pilot, on November 15, 1999, at the Monroe County Medical Examiner's Office, Marathon, Florida. According to the autopsy report, "...Cause of Death...blunt impact trauma caused by aircraft crash into water."
Toxicological tests were conducted at the Federal Aviation Administration, Research Laboratory, Oklahoma City, Oklahoma, and revealed, "No ethanol detected in Kidney... no drugs detected in Kidney...15 (mg/dl, mg/hg) Ethanol detected in muscle...Notes...the ethanol found in this case is from postmortem ethanol formation and not from the ingestion of ethanol."
At 2158:22, the pilot made radio contact with the Miami ARTCC (air route traffic control center), Fort Myers Low Sector Radar Position (R24), and said, "...departing Key West." The controller gave the pilot a transponder code of "four seven zero four."
The pilot called center several times because he did not get the transponder code, and made four attempts to reestablish radio contact.
At 2159:33, the pilot said, "...Miami Center this is uh twin Cessna 4XZ do you copy." The R24 controller answered, "...loud and clear, how me." The pilot of N4XZ said, "...loud and clear sir do you have our uh squawk uh four seven zero four." The controller said, "No sir I do not."
At 2203:04, the R24 controller said, "...radar contact one zero miles north of Key West leaving five thousand five hundred you're cleared to Fort Lauderdale Executive via join victor one fifty seven [V157 airway], Famin [intersection], radar vectors Executive, climb and maintain one one thousand, Key West altimeter zero zero eight."
At 2203:21, the pilot said, "roger uh did you say." The R24 answered at 2203:28, and repeated, "...you're radar contact cleared to the Fort Lauderdale Executive via join victor one five seven to Famin intersection expect radar vectors to Fort Lauderdale climb and maintain one one thousand."
At 2203:41, the pilot of N4XZ said, "roger cleared to Fort Lauderdale Executive via join victor one fifty seven uh maintain one one thousand...." [Note: The piloted omitted the Famin Intersection, and radar vectors on the read back of the clearance.]
At 2203:48, the R24 controller said, "...verify leaving five thousand uh seven hundred." The pilot said, "five thousand seven hundred leaving."
The R24 controller called the pilot 2 minutes 46 seconds later at 2206:38, and said, "...[N4XZ] Miami say heading...N4XZ Miami."
At 2206:50, the pilot of N4XZ said, "Miami stand by." The R24 controller said, "...are you having a problem." There was no response; radio and radar contact was lost.
The R24 controller had several other aircraft on the frequency attempt to make contact with N4XZ without successes.
After the airplane was recovered from the water it was taken to Air and Sea Recovery Inc., Fort Lauderdale, Florida, where the recovered parts were examined.
Examination of the airframe revealed that the components that were recovered included the wing main spar carry-through from the left engine to the right engine, the left aileron, the horizontal and vertical tail section, three seats, the cockpit area to include the power quadrant, center console, the left and right engines, right propeller including all three blades with the hub, two of the left propeller blades and a portion of the left propeller hub.
The fuselage and wing carry through area, out to the wing, displayed extensive impact damage. The leading edges of the wings were missing back to the main spar. The top surfaces of the airplane displayed more impact damage then did the bottom surfaces. Due to the destruction of the fuselage very little recoverable information was available.
The landing gear drive gearbox located on the floor of the fuselage was found in the landing gear retracted position. The flap drive actuator located in the cabin floor was found with the chain drive in an intermediate position about 15 degrees flaps extended.
The power quadrant revealed that the throttle, mixture and propeller were found near the full forward position. The right throttle arm was bent to the rear of the left throttle arm.
The flight controls that were recovered included the horizontal stabilizer, the vertical stabilizer, the right elevator, portions of the rudder, and the left aileron. Flight control continuity was established to a limited extent because of impact damage, and some flight controls were not recovered. The empennage cables and rigging revealed that they had extensive impact damage. No discrepancies were found with the attachments and riggings. The elevator trim tab was found in the 14-degree down position relative to horizontal. The rudder was found beyond limits to the right.
The cabin area was found destroyed. No meaningful information was obtained from the cabin area.
Examination of the fuel system revealed that neither the left nor right wing sections outboard of the engine nacelles were available for inspection to include the main fuel tanks and auxiliary tank. The fuel selector valves were not located. The cockpit fuel selector handles were found and revealed, the left selector handle was found to the Right tank. The right selector handle was found to the Right tank.
Both engines displayed impact damage and corrosion from the seawater. Both oil sumps were crushed upward. The engine exhaust system for both engines displayed impact damage, and parts of both exhaust system were missing. Both of the propellers had separated from the mounting flange. The left engine fuel pump was missing. The right engine-driven fuel was found still attached, and the drive coupler was found in place.
TEST AND RESEARCH
The left and right engines were taken to the facilities of Certified Engines, Opa Locka, Florida, for examination under the supervision of the NTSB, on December 3, 1999. Disassembly and inspection of the left and right engines revealed no discrepancies.
The left and right McCauley propellers were removed for examination, and were taken to Aviation Propellers Inc. facilities, Opa Locka, Florida, on December 8, 1999, under the supervision of the NTSB investigator-in-charge (IIC).
Both propellers displayed impact damage, rotational damage, blade bending, and twisting. The feather stop mechanisms of each propeller were found undamaged, indicating that the mechanisms were not engaged at impact. Neither propeller was at or near the feather position. Impact signature markings to include counterweight impact marks and actuating pin marks indicated that the blade angle of each propeller was found near the low pitch position. No discrepancies were found on either propeller.
The left and right AlliedSignal Model TE0659 turbochargers were removed for examination at Aviation Propellers Inc., facilities, Opa Locka, Florida, on December 8, 1999, under the supervision of the NTSB IIC.
Examination of the left turbocharger part number and serial number unknown revealed that the turbocharger turbine wheel shaft had fractured at the base of the turbine wheel. The turbine wheel shaft, center section, bearings and compressor impeller were not with the turbocharger and not examined.
The turbocharger turbine wheel could not be rotated freely within the turbine housing.
The compressor section, including the V-band compressor housing, compressor impeller, and compressor back plate assembly were not with the turbocharger, and were not examined.
The center section, including the center housing and bearing was not with the turbocharger and was not examined.
The turbine wheel shroud was still attached in the turbine housing by the center section retaining plate. A substance that appeared to be sand was found on all surfaces of the turbine wheel shroud. The shroud was cleaned, and oxidation was observed on the internal surfaces of the turbine wheel shroud. The center bore of the turbine wheel shroud was found elongated. Oxidation was found adjacent to the elongated edges of the center bore. There was a rotational score mark, through about 120 degrees, on the turbine wheel shroud surface adjacent to the turbine wheel, with corresponding rotational score marks on the turbine wheel.
The turbine housing revealed no discrepancies. There appeared to be sand on the internal surfaces of the turbine housing. The housing was cleaned, and oxidation was observed on the internal surface. A rotational score mark was observed, through about 180 degrees, on the turbine-housing shroud surface adjacent to the turbine wheel.
The turbine wheel shaft was found fractured at the piston ring location at the base of the turbine wheel. The separated turbine wheel shaft was not available for examination. Sand was found on all surfaces of the turbine wheel. After cleaning, oxidation and what appeared to be lead deposits were observed on all surfaces.
All turbine wheel blade tips were deformed opposite the direction of rotation. Three turbine wheel tips were found fractured. Two of the three fractured blade tip surfaces were deflected opposite the direction of rotation. A section of the third fractured turbine blade tip was separated from the turbine wheel. There were rotational score marks on the surfaces of the turbine wheel adjacent to the turbine wheel shroud, with corresponding rotational score marks on the turbine wheel shroud.
The wastegate and pressure relief valve were not available for examination.
The V-band clamp and compressor housing appeared to have no discrepancies. A substance that appeared to be sand was found inside the compressor housing. Corrosion was observed on all surfaces of the compressor housing.
Examination of the right turbocharger part number 406610-9025, and serial number XJ028690, revealed that the turbocharger rotor was not free to rotate. The overpressure relief valve and components of the airplane's induction system were still attached to the turbocharger compressor housing.
The compressor section V-band clamp was found attached. The compressor housing did not display any discrepancies, and sand was found inside the housing. After the housing was cleaned, a rotational score mark was observed over 60 percent of the compressor housing shroud surface adjacent to the transition portion of the compressor impeller blades.
The compressor impeller did not display any discrepancies. Corrosion and sand were found on all the surfaces of the impeller. Two of the impeller blade tips were found bent. One was bent in the direction of travel, and the other blade tip was bent opposite the direction of rotation.
The compressor backplate assembly was found in place. Oxidation was found on both the internal and external surfaces of the compressor backplate assembly. The compressor backplate assembly did not display any other damage.
The center section revealed no discrepancies with the center housing, however, corrosion was observed on all surfaces of the housing. Scoring was found on the compressor-bearing surface of the center housing, with corresponding score marks on the compressor bearing. No obstructions were found on the center housing oil passages.
Examination of the bearings did not reveal any discrepancies. Operational discoloration was observed on both bearings. Scoring was observed on the compressor bearing outer diameter, with corresponding score marks on the center-housing compressor bearing surface. The inner diameter and outer diameter of both bearings were measured with a calibrated micrometer. All diameters measured were within service limits. (See the excerpts of Honeywell's teardown report, Table I, page No. 6, an attachment to this report).
The turbine section examination revealed that the turbine housing was found in place. Sand was found on all surfaces of the turbine housing. The turbine housing displayed oxidation on the internal surfaces. The oxidation layer in the interior of the turbine housing was chipped adjacent to the turbine shroud. A rotational scoring mark was found about 0.25 inches in length on the turbine housing outlet adjacent to the turbine wheel blade tips with corresponding rotational score marks found on the turbine wheel blade tips.
The turbine wheel shroud was found with no discrepancies. Coked oil residue was found on the internal surface. Oxidation was observed on all surfaces of the turbine wheel shroud. A rotational score mark was found over about 60 degrees of the turbine wheel shroud adjacent to the backside of the turbine wheel.
The turbine wheel displayed no discrepancies. There was coked oil residue found at the base of turbine wheel. Sand was found on the turbine wheel. The turbine wheel was cleaned and oxidation was observed on all surfaces. Rotational scoring was found on the turbine wheel blade tips adjacent to the turbine housing outlet surface, with corresponding rotational score marks on the turbine-housing outlet.
The turbine rotor shaft displayed operational discoloration. The outer diameters of the bearing journals were measured with a calibrated micrometer. Both bearing journal diameters met service limits. (See the excerpts of Honeywell's teardown report, Table II, page No. 7, an attachment to this report).
Examination of the turbocharger control revealed that the right waste gate part number 470780-16, serial number HH010, was found still attached to sections of the airplane's exhaust system. The airplane's lubrication system fittings and lines were attached to the wastegate oil inlet, outlet and drain ports.
Corrosion and sand were found on the internal and external surfaces of the wastegate and airplane exhaust system parts. The exhaust system was separated from the wastegate, and the wastegate butterfly valve was found in the fully open position. The wastegate actuating linkage did not display any discrepancies. After cleaning, oxidation was observed on the internal surfaces of the wastegate butterfly valve housing.
The wastegate was functionally tested using compressed air. The wastegate operated without any discrepancies when 40-psig of compressed air was applied to the wastegate actuator oil inlet port, with the wastegate actuator oil outlet port blocked.
The pressure relief valve, part number 470930-1, serial number JH143, was found partially attached to the turbocharger compressor housing. The pressure relief valve housing was found dented and had fractured. Sand was found on the external and internal surfaces of the pressure relief valve. The internal pressure relief valve spring and seat displayed no discrepancies.
Two controllers were examined, however their position was not known. The controller identified as No. 1, part number 470948-1, serial number HD0126, did not display any discrepancies. Airplane fittings and lines were still attached to the controller oil and pneumatic ports. Water was present in the airplane's fittings and lines. The controller mounting surfaces did not display any discrepancies, and was still attached to a section of the airplane's structure. Sand was found on the external surfaces of the controller. The controller was not functionally tested.
The controller identified as No. 2, part number 470948-1, serial number IL0136, did not display any discrepancies. Airplane fittings and lines were still attached to the controller oil and pneumatic ports. Water was present in the airplane's fittings and lines. The controller mounting surfaces did not display any discrepancies, and were still attached to a section of the airplane's structure. Sand was found on the external surfaces of the controller. The controller was not functionally tested. (See the excerpts of Honeywell's teardown report, an attachment to this report). Laboratory Examination
Components of the left turbocharger turbine wheel, P/N 406828-9, and wheel shroud, P/N 407778, were sent to the NTSB Materials Laboratory, Washington, D.C. for a more detailed examination. An overview of the components revealed that the turbine wheel contained a 0.4 inches long portion of the separated shaft. The remaining portion of the shaft was not recovered. According to an engineering drawing for the wheel assembly, the shaft was inertia welded to the turbine wheel.
Examination of the turbine wheel shaft revealed that the portion of the shaft still attached to the turbine wheel was subject to corrosion damage. Further examination with a microscope revealed that the shaft separated through the inboard corner of a seal ring groove.
A section containing the fractured end on the shaft, and the adjacent portion of the turbine wheel were cut off from the remaining portion of the wheel for examination with a scanning electron microscope (SEM). After being cleaned the SEM examination revealed that post-separation corrosion damage obliterated most of the microscopic fracture features. The examination did reveal that the fracture surface contained remnants of ductile dimples, which according to the Materials Laboratory Factual Report, was "typical of overstress separation." There was no evidence of progressive fatigue cracking observed.
Examination of the turbine wheel revealed that all turbine wheel blades were bent in the area between the outlet tips and inlet tips. The direction of bending was opposite the direction of the wheel rotation. Two blades were fractured along the bend radii releasing portions containing shroudlines and two blades were cracked. Examination of the fractured faces on the broken and cracked blades revealed rough irregular features, and according to the Materials Laboratory Factual Report, was "typical of overstress separation."
The back face of the turbine wheel contained circumferential rub marks. Heavy rub marks were also noted on the shroudlines of both the intact and cracked blades. Some portions of the wheel were covered with light-colored deposits. The wheel was made from nickel base casting alloy. Energy dispersive X-ray spectroscopy, performed at the surface of a small piece of the blade, generated spectra that contained the peaks of nickel, chromium, iron, titanium, aluminum, and molybdenum, major elements of the wheel material, together with peaks of carbon, lead, and bromine, elements usually found in combustion deposits. The spectra also contained the characteristic peaks of calcium, phosphorous, and oxygen.
Examination of the shroud showed that the shroud was a bowl-shaped component. The back surface of the turbine wheel was assembled close to the bottom of the shroud with the shaft sticking up through the hole in the shroud. A portion of the shroud adjacent to the hole was broken off through an area that comprised approximately 45 percent of the whole circumference. Examination of the fracture surface on the shroud with a microscope revealed features "typical of an overstress separation."
According to a corresponding engineering drawing, the wheel shroud was a cast part and was made from high silicon ductile iron. A wedge-type section was cut from the outer edge of the shroud for metallographic examination. Examination of this section revealed nodules of graphite, typical of the specified material.
The top surface of the shroud contained circumferential rub marks. The pattern of these rub marks was similar to the pattern of rub marks on the mating back surface of the turbine wheel. The clearance between the back of the turbine wheel and the top of the shroud was between 0.97 mm and 1.50 mm.
An impact mark was found in the rim portion of the bowl of the shroud. This portion of the shroud contacts the center housing in the turbocharger assembly. The impact mark was positioned about 15 degrees counterclockwise from the centerline of the fracture. Analysis of the deposits collected from the outside diameter surface of the rim of the shroud, in the area where it meets with the turbine housing generated spectra containing the characteristic peaks of shroud and turbine housing material together with the peaks of light elements usually present in sea water.
The metallurgical examination indicated that the turbine wheel was rotating at the time of impact with the surface of the ocean. The turbine wheel separation, and the fractures of the turbine blades were the result of overstress from rubbing or impact against the turbine housing while rotating. The edge of the hole in the shroud was also the result of overstress due to impact with the rotating shaft. The deposits on the turbine wheel disclosed no abnormalities with combustion process. No abnormal deposits were found on the shroud. (See the NTSB Materials Laboratory Factual Report, an attachment to this report).
On October 26, 1999, the pilot requested that a certified flight instructor (CFI), from CAV-AIR Inc., located at the Fort Lauderdale Executive Airport, accompany him on a 3-hour cross-country flight to satisfy a certification requirement for the FAA Wings Program, Safety Wings Certification. Due to the pilot's schedule the flight took place at night.
According to the CFI's statement, "...[the pilot and the CFI] flew for .7 of an hour on the evening of Wednesday, October 27, 1999. The 3 hour scheduled flight was interrupted because the night altimeter light was inoperative and the right throttle was in the full power position, but the right engine was not generating full power for the altitude. [The pilot] as pilot in command, made the decision to return to [the airport] even though the aircraft had two full operative back altimeters. During the brief flight I observed [the pilot] to be very thorough and safety minded pilot...on the morning of October 28, 1999. [The pilot] telephoned to inform me he was bringing his airplane to the maintenance facility for repair of the night altimeter light and to have the right engine waste gate inspected...he would call me in the future to complete the 3 hour flight...I did not make a log book entry for the flight."
The airplane was released to Mr. Steve Smalley on behalf of Mr. Marshall Dean, insurance adjuster, for the owner's insurance company, on November 18, 1999. The engine turbo charger and propeller were released to Mr. Steve Smalley on December 9, 1999. The turbocharger turbine and shroud were shipped to Mr. Marshall Dean from the NTSB Materials Laboratory, on April 25, 2000, by Registered Mail R866 502 042.