N4507S – Beechcraft (Textron Aviation) A36 – 1998-05-25 NTSB Accident Report

HISTORY OF FLIGHT

On May 25, 1998, at 1501 Eastern Daylight Time, a Beech A36 Bonanza, N4507S, was destroyed during a forced landing about 1/2 mile north of the Newport State Airport (UUU), Newport, Rhode Island. The instrument rated private pilot and one passenger were fatally injured. Two additional passengers were seriously injured. Visual meteorological conditions prevailed at the accident site, however, the pilot had to fly through an overcast layer during the emergency descent. An instrument flight rules flight plan had been filed for the flight between Nantucket Memorial Airport (ACK), Nantucket, Massachusetts, and Danbury (DXR), Connecticut. The personal flight was conducted under 14 CFR Part 91.

The airplane departed Nantucket at 1432, and climbed to 6,000 feet. At 1448, the pilot contacted Providence Air Traffic Control Tower, East Low Radar position. At 1456:01, he told the controller he had "an in-flight problem," and then reported "we've got an engine failure." The controller acknowledged, and advised the pilot that Newport State Airport was at his 9 o'clock position, 6 miles, and that Quonset State Airport was at his 10 o'clock position, about 8 miles. After giving the pilot the option of either airport, the controller told him to "fly a heading two three zero, the Newport Airport will be at twelve o'clock and five miles." The pilot acknowledged the heading. At 1457:06, the controller advised the pilot that Newport State had a Runway 22, that he would line the airplane up for that runway, that it was at 12 o'clock and 5 miles, and that the pilot was cleared to descend to and maintain 2,000 feet. The pilot acknowledged: "two thousand, zero seven."

At 1457:51, the controller requested "...when you have a chance, souls on board and fuel remaining please." The pilot responded with 30 gallons of fuel and four people. At 1458:17, the controller repeated the descent instructions, and said the airport was at 12 o'clock and 3 1/2 miles.

At 1458:58, the controller stated: "The overcast layer's at twenty three hundred feet. There's a few clouds at nine hundred. You should be able to see the airport shortly - it's twelve o'clock and four miles, correction, ah, three miles." The pilot responded with "twelve o'clock, three miles."

At 1459:17, the controller advised the pilot that the length of Runway 22 was 3,000 feet, and that it was at 12 o'clock and 2 miles. This was acknowledged by the pilot.

At 1459:46, the controller stated: "At pilot's discretion, you can maintain fifteen hundred. Airport's twelve o'clock and a mile and a half." At 1459:51 the pilot responded: "Roger, I'm just coming into the overcast now."

At 1459:54, the controller stated: "Okay, should be coming out of it shortly, the airport will be twelve o'clock and a mile and a half. Runway is straight ahead."

At 1500:19, the pilot stated: "Airport's in sight," and the controller responded with: "Roger, you can remain with me until you land." The pilot responded: "Zero seven."

There were no further transmissions from the pilot. During this time, there was a Piper Navajo on the ground and on a different radio frequency at Newport State Airport. At 1500:53, the Navajo pilot stated he had the Bonanza in sight, and at 1501:18 said: "I'm not sure he's going to make it - he's going pretty low." At 1501:25, the Navajo pilot stated "I believe that plane has crashed...." He then reported smoke and fire and: "That plane has crashed, sir... about one-half mile off the end of Runway two two."

Passengers

The two surviving passengers were sitting in the main cabin of the airplane, in the rearward facing seats. Both were initially wearing headsets.

One passenger, who was sitting behind the pilot, remembered that the pilot did a preflight inspection and an engine run-up prior to departure. He also remembered that the takeoff and climb were normal, except for a whistling noise, which the pilot attributed to "water caught in something." It was raining at the time.

The passenger remembered that while the airplane was in level cruise flight, it suddenly and rapidly decelerated. He could not hear anything abnormal from the engine at this point because he still had his headset on. He then heard the pilot "messing with the engine; working the throttle." It sounded like something was clogging the engine, "like choking a non-starting engine; the rpm was going up and down." He didn't hear any alarms go off. He did hear the radios, and the pilot talking to both air traffic control and his daughter.

At this point, the engine was still operating, and the airplane turned. The passenger thought the airplane was going back toward an airport he had seen. The turn happened "relatively quickly after the problem started." The passenger said the weather was "relatively clear," and he could see the ground. He didn't remember passing through any cloud layers during the descent, but wasn't sure. He was alternately looking both forward, "at peoples' faces," and aft.

The passenger remembered three distinct phases of the event. The first started when the engine began to exhibit a problem, and included the initial steps taken toward trying to solve the problem, as well as the initial turn made by the pilot. The second phase consisted of "time passed" while the airplane was in a descent, and the passenger looking alternately forward and aft. The last phase began when the engine became silent.

When the engine became silent, the passenger looked forward, and heard the pilot's daughter tell her father to restart the engine, to which he responded: "I can't." The passenger then looked toward the intended runway, just over the trees, and thought there was "no way we can make it that far." Just after that, he heard an alarm going off. He then turned back in the seat, faced aft, and buried himself down into the seat until he felt the impact.

The passenger also recalled that in the last phase, the airplane made a left turn, "like a last ditch effort - plan 'B'." He thought one wing went up and one wing went down, perhaps to a 45 degree angle, but was just guessing. He thought that the left wing went down, but could not remember if the pilot held the turn or not.

The passenger remembered hitting the ground, then bouncing. It was a "pretty hard" hit and his eyes were closed. After the airplane stopped, he opened his eyes, and remembered being in smoke and fire. For a few seconds, he might have blacked out.

The passenger got out the plane via the right, aft passenger access door with the other passenger. He did not hear any sounds from the people in the front seats.

When asked, he did not recall if or when the pilot lowered the landing gear prior to impact.

The other passenger was sitting behind the right, front seat passenger. He stated that there was nothing unusual about the airplane, or the startup or takeoff, except for the new headsets. After takeoff, the passenger heard a whistling sound, "like blowing in a bottle." He said that the pilot explained that it was "water or something" and it had just been looked at by maintenance personnel. Aside from the sound, the climbout and level off were uneventful. Everything was "status quo" until the sound of the engine changed, from "humming along" to what it normally sounded like when an engine shut down.

The passenger had unplugged his headset, and didn't hear many conversations from the front seats or any from air traffic control. He said that during the emergency descent, he and the other back seat passenger tried to reassure each other, and that at one time, he did hear the pilot's daughter suggest another engine restart attempt. The passenger did not remember entering any cloud layers, but remembered that when the airplane exited the last layer of clouds, he heard a horn go off. It was originally intermittent, then transitioned to a solid "wahhh" sound, and remained on until ground impact.

The passenger remembered turning around in his seat at one point, and looking forward. He saw trees, and had a funny feeling that the runway was on the other side of them. He then knew "there was no shot of getting to the runway," and that the airplane was going to crash. He turned back around to face aft, and remembered the airplane "banked left and came around. He did not remember the actual impact, but did remember being on fire, screaming, and looking at the door and not knowing how to open it. He said the other passenger got up and opened the door, then doesn't remember anything else until he was out of the airplane and in the bushes.

The passenger did not remember if or when the pilot lowered the landing gear.

Witnesses

Three witnesses were interviewed, two of whom were in an airplane waiting to take off from Newport State Airport.

One witness was at his cottage in Tiverton, Rhode Island, about 12 nautical miles northeast of Newport State. He was inside the house, and heard "routine engine noise" which abruptly stopped. A few seconds later, the sound returned, then stopped again. The witness said he couldn't imagine a throttle being intentionally brought up and back at that rate. It was like there was no noise, then full throttle, then no noise again. The witness than ran outside and noted the time, which was around 3:00 p.m.

The two witnesses who were in the Piper Navajo were waiting to takeoff from Runway 22 at Newport State, where the accident airplane was being vectored.

One witness was sitting in the back of the Navajo. She stated that she saw the accident airplane come out of the clouds, and based on its position, was surprised it didn't make it to the airfield. She said that she thought the pilot lowered the landing gear too soon, but she did not actually see the landing gear come down. Still, she wondered: "How come he came down so fast?"

The witness did not see the accident airplane make any turns once it came out of the clouds. She saw it lined up with the airport, and then it disappeared below a tree line. She also noted that there were several open fields in the vicinity of the accident.

Another witness was the pilot of the Navajo. He saw the accident airplane come out of the clouds, then level off. It appeared to be 1/2 to 1/4 mile from the runway at the time. It then dropped fast, and disappeared below a tree line. The witness further described the accident airplane as being on a reasonable glideslope before it leveled off. Then it "went up slightly, then right down, forward."

The witness said he thought the accident airplane may have lowered its landing gear too soon, but also said he did not actually see the landing gear come down. He noted that the accident airplane came in straight, without making any turns during the approach.

The witness also stated that when his airplane took off approximately 15 to 20 minutes after the accident, it entered the cloud layer about 2,000 feet.

The accident occurred during the hours of daylight. The accident site was located at 41 degrees, 32.54 minutes north latitude, and 071 degrees, 16.47 minutes west longitude.

PERSONEL INFORMATION

The certificated private pilot was single-engine, multi-engine, and instrument rated. His logbook was destroyed in the post-crash fire. His most recent Federal Aviation Administration (FAA) Third Class Medical Certificate was issued on November 11, 1996, and on his application he reported that he had 400 hours total flight time. He purchased the accident airplane in November, 1996, and it flew an estimated 375 hours prior to the accident.

Both surviving passengers had flown with the pilot before. One stated that he did not normally feel safe in smaller airplanes, but felt safe with this pilot, who was very detail-oriented. The other passenger said he had no concerns about flying with the pilot, and "felt fine," in fact, "loved it."

AIRCRAFT INFORMATION

The airplane was a 1975 Beech A36, serial number E-722. It was powered by a single Continental IO-520-BA(12) engine, which developed 285 horsepower. The engine, serial number 249251-R, was rebuilt by Teledyne Continental Motors on March 21, 1985. It was installed in the airplane on April 17, 1985.

The airplane had been maintained by Master Aviation, Incorporated, Danbury, Connecticut, since December, 1986. On December 20, 1989, the number 2 and number 3 engine cylinders were removed and replaced by Hangar One Incorporated, Orlando, Florida. On October 30, 1996, a prepurchase inspection was done on the airplane, on behalf of the accident pilot, by a New York maintenance facility, Curtiss Aero. At that time, the airplane tachometer registered 2099.1 hours. On October 3, 1997, Master Aviation personnel removed the propeller for overhaul. According to an invoice from an independent propeller shop, the propeller was "not economical to repair." The propeller shop manager stated that the propeller could not be brought into tolerances economically, and that there had been no indication of a prop strike.

On February 20, 1998, all six engine cylinders were replaced with factory new cylinders at Master Aviation during an annual inspection. At that time, the aircraft logbook indicated 2,441.8 tachometer hours.

An Airframe and Powerplant (A&P) mechanic with Inspection Authorization (IA), signed off the annual inspection. He supervised another A&P who actually changed the cylinders. The supervising IA stated that the work was performed in accordance with the maintenance manual provided on micro fiche by Aircraft Technical Publishers, Brisbane, California. Torque settings were verified with a calibrated torque wrench, which was calibrated with an on-site torque wrench tester before being used on the airplane. When asked if he remembered how, to what degree, and whether the torque's were set using wet or dry bolts and threads, the IA stated that he could not do so offhand, that he would have to have the a maintenance book in front of him to be exact, and that he would do whatever the book said to do.

When asked if the engine had been split at any time during the maintenance, the IA was emphatic in that it was not.

The IA said he didn't have any ideas of what might have happened to the engine because he did not have all the facts. He did say that the airplane had been in "terrific shape." He said that he wouldn't have expected problems with either the accident airplane or the accident pilot. He also noted that the owner of the maintenance facility, himself an A&P with IA, had flown the airplane on numerous occasions.

The A&P mechanic who changed the cylinders said that during the maintenance, he used Continental engine overhaul manuals and backed them up with service bulletins. He said that the IA's role was to inspect and overlook his work. "The way we work it; very professional; nothing gets overlooked; everything checked, rechecked; engine run several times; torques checked per manual with a calibrated torque wrench." The torque wrench was calibrated on the day of the maintenance with a torque wrench tester.

When asked if the torques were set "wet" or "dry," the A&P stated he could not remember which was done. "We work on several different aircraft; do top overhauls on a regular basis and always go back to the manuals because there are so many different manuals and installation procedures."

When asked if he split the engine casing during the cylinder change, the A&P said: "No, we don't have the equipment. If it's that extreme, it goes to the manufacturer."

The A&P stated that he didn't remember any problems occurring during the change of the cylinders. It was a "flawless installation; the aircraft ran like a top; [the pilot] was ecstatic with how it ran."

The Continental engine overhaul manual required the use of castor oil to set wet torques, while Service Bulletin SB96-7B stated that torques should have been set using 50 weight aviation oil. The owner of Master Aviation said that 50 weight aviation oil was used and that castor oil was not on the premises.

The engine's oil had been analyzed at various times between 1990 and 1997 by Cleveland Technical Center, Cleveland, Ohio. Spectrochemical analysis performed on May 31, 1990, resulted in an iron level reading of 55 parts per million (ppm) by weight, and an advisory that: "Iron level appears to be high." Testing on March 4, 1992, resulted in an iron level reading of 73 ppm, but no advisory. Testing on June 2, 1992, resulted in an iron level reading of 48 ppm, and a .25 percent volume of water, with an advisory that "Test results indicate the presence of water." Testing on July 30, 1993, resulted in an iron level reading of 138 ppm and an aluminum level reading of 22 ppm. The advisory read: "Wear metals high - indicating possible cylinder wear and piston scuffing." Testing on September 21, 1994, resulted in an iron level reading of 114 ppm, and an advisory that: "Iron level appears high." The last known testing, on July 19, 1997, resulted in an iron reading of 22 ppm, and the statement that "...No corrective action [was] required." Contact with Cleveland Technical Center revealed that there were no other test results on file.

On April 29, 1998, the airplane was repainted and the cabin reupholstered at Hawk Aircraft Painting, Tampa, Florida. At that time, tachometer hours were listed as 2,467.0.

METEORLOGICAL INFORMATION

Visual meteorological conditions prevailed near the crash site. Newport State Airport was served by an Automatic Surface Observation System (ASOS) facility, which recorded the following weather at 1453: winds from 180 degrees magnetic at 10 knots, visibility 4 statute miles in light rain and mist, a few clouds at 900 feet, overcast at 2,300 feet, temperature 12 degrees Celsius, dewpoint 12 degrees Celsius, and altimeter 29.90 inches of mercury.

WRECKAGE AND IMPACT INFORMATION

The wreckage was located approximately 1/2 mile northeast of the approach end of Runway 22 at Newport State. All major airplane components were found at the scene.

The surrounding area consisted of pastureland and fields, bordered by stone walls, some housing, and some wooded areas. Northeast of Runway 22 was one of the wooded areas. It was bordered on the north by a stone wall, which was oriented approximately east-west. The main wreckage was located just south of, and next to the stone wall, slightly to the right of the Runway 22 extended centerline. Scrape marks and displaced stones were found on, and next to the stone wall, perpendicular to its axis.

The airplane came to rest with its longitudinal axis almost parallel to the stone wall. Three feet in front of the right wing was a large, charred tree. Scrape marks were found on the tree at 3 feet, 7 inches, and 7 feet, 2 inches above the ground. A smaller tree was located 5 feet south of the wall, 18 feet east of the large tree, behind the right wing. Bark was peeled away about 6 feet above the ground, but the tree was not charred.

To the north of the stone wall was a large pasture, about 400 feet in width and over 1,300 feet in length, also oriented east-west. A series of ground marks, approximately 31 feet in length, commenced about 50 feet northeast of the wreckage, and extended southwest along an axis of 210 degrees magnetic, toward the stone wall. At the beginning of the marks, the right main landing gear inboard door was found imbedded in the ground to a depth of 12 inches.

One propeller blade was bent back approximately 15 degrees, and there was very little bending or damage to the other. No chordwise scoring marks were found on either blade.

Both fuel tanks were ruptured. A small amount of residual fuel was found in the right tank, and was blue and clear. The engine fuel pump turned freely.

The cockpit and cabin areas were destroyed by fire. Control continuity was established in both wings and the tail section.

The engine was removed and examined at a nearby hangar. Examination revealed a 4-inch semi-circular crack on the top, left half of the crankcase near the centerline. It was between the number 2 and number 4 cylinders, just below the lifting lug. When the propeller was rotated by hand, movement was observed from the two most forward cylinders (5 and 6). No movement was observed from any of the other four cylinders, nor from any accessory gears on the aft part of the engine. When the accessory gears on the aft part of the engine were rotated by hand, only the two aft-most cylinders (1 and 2) moved.

The spark plugs were light gray to dark gray in color, except for two plugs, which were oily. Both magnetos produced spark. The engine-driven vacuum pump drive coupling was rotated, and the vanes were intact.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed on the pilot and the deceased passenger by the Rhode Island Department of Health, Office of Medical Examiners, Providence, Rhode Island.

Toxicological testing was performed on the pilot by the FAA Toxicology Accident Research Laboratory, Oklahoma City, Oklahoma.

TESTS AND RESEARCH

Radar

Radar tracking data was recovered, and the airplane's track plotted. Radar reflections (hits), varied in spacing from 4, to 5 seconds' interval. According to the data, the airplane was initially traveling on a northwest heading, about 310 degrees magnetic, with approximately 162 knots of groundspeed, at 6,000 feet. When the pilot first notified approach control of the engine problem, the airplane was decelerating. The airplane then began a descent, and was turned toward Newport State. Upon completion of the turn, the airplane was about 6 nautical miles, and 4,000 feet above the ground. During the descent, the airplane maintained a rate of descent of 1,300 to 1,400 feet per minute, and maintained a groundspeed of 111 to 116 knots. At 2,800 feet, the airplane's groundspeed was about 90 knots. Just after passing 1,800 feet, at 88 knots groundspeed, the pilot announced that he was entering an overcast. At 1500:19, with the airplane's altitude readout at 1,200 feet and the groundspeed at 81 knots, the pilot reported the airport in sight. During the next two radar hits, the airplane's altitude remained at 1,000 feet, and the groundspeed slowed to 77 knots. The following two hits showed the airplane at 900 feet, and the groundspeed at 74 knots. The next two hits were at 800 feet, with the groundspeed at 70 knots. One hit was made at 700 feet, then two more at 600 feet, with the groundspeed at 67 knots. The next two hits were at 500 feet, with a constant groundspeed of 65 knots. The following two hits were recorded at 400 feet, with the groundspeed down to 62 knots. The final hit was at 200 feet, with a groundspeed of 60 knots.

The elapsed time between the point where the pilot said he had the airport in sight, to the final radar hit at 200 feet, was about 1 minute, 7 seconds. According to computer analysis, the airplane's heading varied from 236 degrees magnetic at 1,200 feet, to 212 degrees magnetic at 600 feet. It then changed to 229 degrees magnetic at 400 feet, and 220 degrees magnetic at 200 feet.

Engine

The engine was shipped to Teledyne Continental Motors for teardown and inspection under Safety Board supervision. During disassembly, break-away torque was found on all cylinder bolts, ranging from a low of 30 foot-pounds to a high of 65 foot-pounds.

Minor fretting was found on both crankcase halves, around the through-bolt holes at the number 2 bearing saddle, where the two crankcase surfaces met.

The crankshaft, serial number 316, was broken at the number 4 cheek, just forward of the number 2 main journal, and at the number 6 cheek at the aft portion of the number 3 main journal. The number 3 connecting rod was broken off the crankshaft journal.

Crankshaft main bearing number 2 was "pounded," and covered the oil feed hole. The number 3 main bearing exhibited bluish gray, and brown discoloration. Both crankcase halves exhibited similar damage signatures.

The oil sump and oil filter exhibited copious amounts of metal fragments.

The crankshaft and the numbers 2 and 3 bearings were boxed up, and shipped directly to the National Transportation Safety Board Metallurgy Laboratory for examination.

According to the Laboratory's factual report, almost all of the features of the fracture surface just forward of the number 2 main journal "had been obliterated by gross mechanical damage and associated overheating. Because of this damage, the examination was limited to the aft fracture face." The fracture face was cut from the remainder of the crankshaft, and "to remove loose deposits from the fracture surface...[it] was cleaned in an ultrasonically agitated acetone bath."

"The perimeter of the fracture face had also been damaged, apparently by post-separation rotational contact with the mating forward face. However, examination of the relatively undamaged central portion of the fracture revealed smooth fracture features and crack arrest positions indicative of high cycle fatigue cracking. The fatigue cracking emanated from three origin areas....Examination of the radius on both sides of the origin areas revealed the presence of bearing rub marks and associated ladder cracking...the fatigue cracking appeared to have initiated from one of these ladder cracks. Evidence of overheating and ladder cracking were found in other areas of the number 2 main bearing journal."

"Both bearing halves, reportedly removed from the number 2 main journal, contained gapping cracks along lubrication grooves. The entire edge on one bearing shell was lipped over and had the approximate shape of the radius between the journal and the crank cheek. A small area of the edge in the second bearing shell was also found lipped over. Both bearing halves appeared to have been flattened, as if by excessive compressive loads."

The fracture just forward of the number 3 main bearing journal "was relatively rough and was found to contain a small number of crack arrest positions. Features in fracture areas...were typical of fractures produced by an overload....The number 3 main bearing journal exhibited evidence of severe overheating. [A] set of bearing shells, reportedly removed from the number 3 main bearing journal, contained evidence of severe overheating. The lubrication grooves in both bearing halves were packed with solidified oil deposits and residue of bearing material."

ADDITIONAL INFORMATION

In the Beechcraft Bonanza 36, A36, E-1 thru E-926 Pilot's Operating Handbook and FAA Approved Airplane Flight Manual, the following was provided:

MAXIMUM GLIDE CONFIGURATION

1. Landing Gear - UP 2. Flaps - UP 3. Cowl Flaps - CLOSED 4. Propeller - PULL for LOW RPM 5. Airspeed - 110 kts/127 mph

"Glide distance is approximately 1.7 nautical miles (2 statute miles) per 1000 feet of altitude above the terrain."

STALL WARNING

"A stall warning horn on the forward side of the instrument panel sounds a warning signal as the airplane approaches a stall condition....Irregular and intermittent at first, the warning signal will become steady as the airplane approaches a complete stall."

EMERGENCY AIRSPEEDS

Emergency Descent ............................ 153 kts/176 mph Glide ............................................. 110 kts/127 mph Emergency Landing Approach .............. 81 kts/93 mph

CAUTION

"The approach airspeed is higher than normal to assure the availability of control during flare without power."

WRECKAGE RELEASE

The airplane wreckage, less the engine, was released to Ryan Insurance Services, Inc., Biddeford, Maine on May 27, 1998. The engine, with the exception of the crankshaft with one connecting rod, and the numbers 2 and 3 main bearings, was released to Ryan Insurance Services, Inc. from the Teledyne Continental facility on June 18, 1998. On October 20, 1998, the remaining engine parts were forwarded to Ryan Insurance Services, Inc. from the Safety Board.