N4548S

HISTORY OF FLIGHTOn November 15, 2014, about 1606 eastern standard time, a Beech F33A, N4548S, was substantially damaged when it impacted trees during a forced landing, after a loss of power during cruise near Clinton, Connecticut. The pilot received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under Title 14 Code of Federal Regulations Part 91, which departed Groton-New London Airport (GON), Groton, Connecticut, destined for Orange County Airport (MGJ), Montgomery, New York.

According to the pilot, earlier in the day she had flown the airplane from MGJ to GON. She had approximately 20 gallons of fuel in each wing tank prior to departure. She did not refuel at GON.

At approximately 1555, she departed on her return flight to MGJ. After takeoff she made a left turn and established herself on course. She then climbed to 4,500 feet above mean sea level and trimmed for cruise flight, set 2,300 revolutions per minute (rpm), manifold pressure to 23 inches of mercury, and fuel flow to 13 gallons per hour.

Sometime later, air traffic control (ATC) pointed out traffic to the pilot however, the sun was directly ahead of her, and very bright, making it difficult for her to see. She then advised ATC that she was looking for traffic, and shortly afterwards, she heard "a loud explosive bang - like a gunshot." She immediately checked her instruments. The rpm had risen to "over 2,500 rpm – over redline." She then reduced the propeller control back with no effect. The airplane started to "shudder – physically shaking me." The rpm on her tachometer had now dropped to 2,000. Her airspeed had also dropped off and she began to lose altitude. She then checked her propeller setting and aggressively advanced the propeller, but there was no increase in rpm.

She contacted ATC and told them she had engine problems and declared an emergency. ATC advised her to land at Chester Airport (SNC), Chester, Connecticut, which was the nearest airport. She then requested vectors to SNC. They advised her to turn to a heading of 180° which she did. She advised ATC that she did not see the airport, nor did she see any other clearing or road. All she saw were trees, and she continued to lose altitude. She flew the airplane straight and level, as best she could, trying to maintain the airplane's best glide speed. She called ATC again requesting the location of the airport. They advised her that it was about 2 miles at her 12 o'clock position. However, she still could not see it. She realized at this point that she was not going to find the airport or any other open area before she hit the trees.

She continued to fly the airplane straight and level and decided not to put the landing gear down as she was aiming to land the airplane on top of the trees, hoping they would cushion the airplane as it descended to the ground. She reached down to shut the fuel selector off because she was afraid there might be a fire once she crashed. She knew there was still plenty of fuel on board. However, since she did it as she was approaching the tree tops, she could not look at the fuel selector handle to check its setting. She knew she turned the handle, but she was not sure if she had fully turned it to the left to the "OFF" position from the right tank before the airplane then collided with the trees. PERSONNEL INFORMATIONThe pilot held a Federal Aviation Administration (FAA) commercial pilot certificate with ratings for airplane single-engine land, and instrument airplane. Her most recent FAA second-class medical certificate was issued on August 25, 2014. She reported that she had accrued approximately 1,549 total flight hours, 827 of which, were in the accident airplane make and model. AIRCRAFT INFORMATIONOn November 4, 1999, in accordance with FAA Supplemental Type Certificate SA2200SW, the installed Continental IO-550-BA engine was replaced with a 300 horsepower, air cooled, 6-cylinder, horizontally opposed, Continental IO-550-B equipped with a Hartzell 3-bladed, variable pitch, constant speed propeller.

Its most recent annual inspection was completed on February 22, 2014. At the time of the accident, the airplane had accrued 3,016.02 total hours of operation, and the engine had accrued 866.72 total hours of operation since major overhaul. METEOROLOGICAL INFORMATIONThe recorded weather at Chester Airport (SNC), Chester, Connecticut, located 3.7 nautical miles north of the accident site, at 1555, included: winds 320° at 7 knots, 10 miles visibility, sky clear, temperature 3° C, dew point -11° C, and an altimeter setting of 30.27 inches of mercury. AIRPORT INFORMATIONOn November 4, 1999, in accordance with FAA Supplemental Type Certificate SA2200SW, the installed Continental IO-550-BA engine was replaced with a 300 horsepower, air cooled, 6-cylinder, horizontally opposed, Continental IO-550-B equipped with a Hartzell 3-bladed, variable pitch, constant speed propeller.

Its most recent annual inspection was completed on February 22, 2014. At the time of the accident, the airplane had accrued 3,016.02 total hours of operation, and the engine had accrued 866.72 total hours of operation since major overhaul. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site and wreckage revealed that the airplane came to rest inverted, in a nose and left wing down position, wedged between trees, about 6 feet above ground level.

Airplane Examination

Examination of the airplane revealed that the wings, fuselage, engine, and empennage were impact damaged. Control continuity was established to the ailerons, elevators, and rudder. The wing flaps were retracted, and the flap selector switch was in the up (retracted) position. The elevator trim position indicator displayed about a 6° nose up trim position.

The landing gear was retracted, the landing gear selector was in the up (retracted) position, and the emergency gear extension handle was stowed. The magnetos switch was in the left magneto position. The battery master and alternator switches were on, the auxiliary instrument air switch was in the on position, the pitot heat switch was in the off position. The strobes, electronic flight instrumentation, and navigation lights switches, were in the on position.

The throttle control was in the full open position, the mixture control was in the full rich position, and the propeller was in the high rpm position. The auxiliary fuel pump was off, and the cowl flaps were open.

First responders did not report an evidence of a fuel spill though both the left, and right, wing tip tanks, and the left, and right, wing fuel bladders were breached. The tip tanks were totally devoid of fuel, but fuel was discovered to be trapped in the undamaged portion of each of the wing tank's fuel bladders. About 17 gallons of fuel was recovered from the right-wing tank. Less than 1 gallon of fuel was recovered from the left-wing tank. The fuel selector was in the "LEFT TANK" position. The fuel strainer was clean, free of debris, and devoid of fuel. No fuel was recovered from the fuel supply line to the engine driven fuel pump.

Propeller Examination

The propeller had remained attached to the engine; and the blades had remained secured in the hub.

On January 27, 2015, the propeller was examined at Hartzell Propeller Incorporated.

During the examination it was discovered that the spinner dome was crushed on one side and was still attached to the spinner bulkhead, which was intact, but was bent around the edges. The engine to the propeller mounting was intact and unremarkable.

One propeller blade was unremarkable, the tip of the other two propeller blades were bent aft. None of the blades displayed leading edge impact damage.

The cylinder, piston, pitch change rod, fork, spring, and low and high pitch stops, were all intact and unremarkable. The hub assembly was also intact and unremarkable, and the preload plates displayed normal wear.

The blade bearings were all intact and unremarkable. Two of the pitch change knobs were fractured off. Metallurgical examination indicated that they had failed by ductile overload under shear or tearing stresses, with no indication of fatigue cracking.

Engine Examination

On March 24, 2015 the engine was examined at Continental Motors Incorporated (CMI).

Examination revealed that the engine had sustained impact damage during the accident sequence, and all the fuel lines going to the fuel metering assembly had broken free from the assembly. The fuel inlet fitting going to the engine driven fuel pump had broken free from the fuel pump. The ignition harness displayed tearing in several locations; however, none of the ignition lines were severed. All four engine mounts were broken consistent with impact damage. The right-side exhaust displayed bending deformation consistent with impact damage and the intake balance tube was crushed.

The fuel pump was disassembled, and the internal components were inspected. There were no anomalies noted with the engine driven fuel pump. The cylinders were examined using a lighted borescope and the pistons, cylinder bore, and valve heads displayed normal operating and combustion signatures.

The magneto-to-engine timing was then checked and compared to the specified magneto to engine timing of 22° before top dead center (BTDC) with the following results:

Left Magneto: 25° BTDC

Right Magneto: 23° BTDC

A cylinder leakage test was then performed in accordance with the latest revision of CMI Service Bulletin SB03-3 with the engine at room temperature with the following results (master orifice reading – 39 PSI):

Cylinder No.1 - 26/80 PSI

Cylinder No.3 - 6/80 PSI

Cylinder No.5 - 10/80 PSI

Cylinder No.2 - 36/80 PSI

Cylinder No.4 - 39/80 PSI

Cylinder No.6 - 50/80 PSI

The leakage source for all 6 cylinders were the exhaust valves and piston rings.

Engine Run

After the examination, the engine was prepared for an engine run by removing the propeller gove...