Thursday, January 19, 2012

Piper PA-24-180 Comanche, N7648P: Fatal accident occurred January 15, 2012 in Brewster, Massachusetts

NTSB Identification: ERA12LA145 
14 CFR Part 91: General Aviation
Accident occurred Sunday, January 15, 2012 in Brewster, MA
Probable Cause Approval Date: 05/23/2013
Aircraft: PIPER PA-24-180, registration: N7648P
Injuries: 2 Fatal.

NTSB investigators may have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot was practicing instrument approaches with a flight instructor. While in a holding pattern, an air traffic controller contacted the pilot after observing his erratic altitude control. The pilot responded, “there’s smoke in the cabin.” About 24 seconds later, the pilot stated that “we’ve cleared the smoke” and that they would continue the flight. This was the last transmission received from the pilot, and it was cut off, and radar contact was then lost. The airplane subsequently crashed into Cape Cod Bay. General fragmentation of the wreckage indicated a high-energy impact with the water. Examination of the wreckage did not reveal any evidence of an in-flight fire or other anomaly or malfunction that would have precluded normal operation. Examinations of several electrical components, including avionics, wires, and circuit breakers revealed no evidence of overheating or fire.

A study of weather data revealed that, at the time of the accident, the airplane was in instrument meteorological conditions with snow. The National Weather Service Current Icing Product indicated a greater than 50 percent chance of icing at 2,000 feet, which was near the altitude of the airplane before the accident. However, the pilot did not mention icing conditions to the controller.

The pilot tested positive for several medications during postaccident specimen analysis, including diazepam, nordiazepam, tramadol, and warfarin. Since the blood samples obtained were collected from a body cavity, the assessment of pilot impairment was not reliable due to concerns with postmortem redistribution of drugs. The pilot had not reported these medications on his latest third-class medical certificate application. The pilot and flight instructor both tested negative for carbon monoxide and cyanide.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The flight crew’s loss of airplane control.


On January 15, 2012, about 1005 eastern standard time, a Piper PA-24-180, N7648P, crashed into Cape Cod Bay near Brewster, Massachusetts. The airplane was registered to a private individual and was operated by a private pilot. Instrument meteorological conditions prevailed at the time and an instrument flight rules flight plan was filed for the instructional flight from Vineyard Haven, Massachusetts (MVY) to Hyannis, Massachusetts (HYA). The flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. The airplane was substantially damaged. The private pilot and a flight instructor were fatally injured.

The pilot filed a flight plan and obtained a weather briefing through the Direct User Access Terminal System (DUATS) at 1459 on January 14, 2012, the day prior to the accident. The following remark was noted on the DUATS flight plan, “Practice Approaches - PIC: Robert Walker.”

According to his wife, the pilot was practicing instrument procedures as part of an instrument proficiency check. After performing two practice approaches, the pilot requested four turns in holding at MECEJ holding fix. After the pilot reported that he was established in the holding pattern at MEJEC, at 1504:01 (HHMM:SS), the controller queried the pilot on his altitude control, stating that the aircraft altitude was varying by 500 feet. The controller asked the pilot if he needed assistance, and the pilot replied, at 1504:09, “there’s smoke in the cabin.” At 1504:24, the pilot stated, “we’ve got to clear the smoke and uh…” At 1504:33, the last transmission was received from the pilot, “four eight pop I guess we’ll sit we’ll stay in the uh we’ve cleared the smoke we’ll stay in the uh…” Radar and radio contact was subsequently lost.

The pilot’s wife listened to the recorded ATC voice communications after the accident and reported that the voices from the aircraft related to smoke in the cabin were that of her husband, the pilot.

Recorded radar data indicated that, at 1504:05, the aircraft was proceeding in a westerly direction at 2,200 feet above mean sea level (msl). The last reliable radar return, at 1504:45, indicated that the airplane had commenced a right turn and descended to 1,300 feet msl. The wreckage was located about 0.3 nautical miles southeast of the last radar return.



The pilot held a private pilot certificate with ratings for airplane single-engine land and instrument airplane. On an insurance application dated January 9, 2012, he reported 676 hours total time, including 111 in the PA-24. His latest document flight review occurred on October 22, 2011.

Flight Instructor

The flight instructor held a commercial pilot certificate with ratings for airplane single-engine land, airplane multiengine land, airplane single engine sea, instrument airplane, ground instructor, and flight instructor (airplane single-engine and multiengine, instrument airplane). He reported 7,384 hours of total flight experience on his latest Federal Aviation Administration (FAA) second class medical certificate, dated March 30, 2011.


The airplane was a single-engine, low wing, retractable gear airplane, serial number 24-2862. It was powered by a Lycoming O-360-A1D engine rated at 180 horsepower at 2,700 rpm. The tachometer (tach) time observed in the wreckage was 5,049.3 hours.

The aircraft was equipped with an electrically-heated pitot tube. The aircraft was not equipped with ice protection on the wings, stabilator, or vertical stabilizer and was not certificated for flight in icing conditions.

According to the aircraft maintenance records, the last recorded maintenance on the airplane occurred on December 16, 2011, at tach time 5,032.1 hours. The following entry was noted, “Checked for inoperative charging system, alternator circuit breaker found tripped, checked all alternator wiring from firewall forward, found that a 50 amp alternator circuit installed did not match 60-amp breaker called for in InterAv wiring diagram, 50-amp breaker previously approved by FAA form 337 dated 1/20/03, checked alternator brushes, adjusted alternator belt tension, ran engine several times and found charging system working properly, could not duplicate circuit breaker tripping. Replaced both wing tip navigation lamps P/N A7512-12.” The 50-amp circuit breaker was not replaced during the maintenance on December 16.

The last annual inspection on the airplane occurred on July 2, 2011, at tach time 4,983.9 hours.

On June 11, 2008, during an annual inspection, the master circuit breaker was removed and replaced with another 50 amp circuit breaker, part number W23X1A1G50.

The pilot’s wife reported the following maintenance discrepancies during an interview following the accident. In November, 2011, the landing gear would not extend and the alternate extension system was required to lower the gear. On January 4, 2012, the volt meter and amp meter were discharging. She stated that the airplane flew several times after that with no issues. There were no aircraft logbook entries to document the events.

According to the FAA, on December 27, 2011, the pilot was involved in an ATC deviation, and the pilot cited radio problems in his explanation of the event. ATC reported that the pilot did not respond to radio calls and deviated from his last assigned heading and altitude. The aircraft logbook did not include an entry related to a radio repair for the flight of December 27.


The closest weather reporting facility to the accident site was Chatham Municipal Airport (CQX), Chatham, Massachusetts, located about 8 miles southeast of the accident site at an elevation of 63 feet. The CQX weather observation at 0952 reported wind from 320 degrees at 10 knots gusting to 16 knots, visibility 7 miles in light snow, ceiling overcast at 1,600 feet above ground level (agl), temperature 9 degrees Celsius (C), dew point minus 13 degrees C, and altimeter setting 30.20 inches of mercury (Hg). Remarks included hourly precipitation less than 0.01 inch or trace and 6-hour precipitation total less than 0.01 inch.

The CQX special weather observation at 1012 included wind from 300 degrees at 11 knots gusting to 19 knots, visibility 1 3/4 miles in light snow, ceiling overcast at 1,800 feet, temperature minus 8 degrees C, dew point temperature minus 13 degrees C, and altimeter setting 30.21 inches of Hg. Remarks included hourly precipitation less than 0.01 inch.

A review of the observations indicated that snow first began at Chatham at 0645 EST and continued through the time of the accident with a few periods of brief instrument flight rules (IFR) conditions in a few heavier snow showers.

The next closest weather reporting facility to the accident site was from Barnstate Municipal Airport – Boardman/Polando Field (HYA), Hyannis, Massachusetts, which was the destination of where the practice instrument approach was planned and was located approximately 10 miles southwest of the accident site at an elevation of 54 feet.

The HYA weather observation at 0956 included wind from 310 degrees at 14 knots gusting to 20 knots, visibility 1 1/2 miles in light snow, ceiling overcast at 1,900 feet, temperature minus 11 degrees C, dew point temperature minus 15 degrees C, and altimeter setting 30.21 inches of Hg. Remarks included that snow began at 0913 EST, hourly precipitation less than 0.01 of an inch, and 6-hour precipitation less than 0.01 of an inch.

The HYA weather observation at 1056 included wind from 320 degrees at 12 knots gusting to 21 knots, visibility 1 mile in light snow, ceiling broken at 1,700 feet, overcast at 2,600 feet, temperature minus 11 degrees C, dew point temperature minus 14° C, and altimeter setting 30.21 inches of Hg. Remarks included hourly precipitation less than 0.01 of an inch.

A review of the raw observations indicated that snow first started at HYA at 0913 and continued through the time of the accident.

The accident airplane departed from Martha’s Vineyard Airport (MVY), Vineyard Haven, Massachusetts, located approximately 32 miles southwest from the accident site at an elevation of 67 feet. The MVY weather observation at 0853 included wind from 340 degrees at 12 knots gusting to 19 knots, visibility 10 miles, sky clear below 12,000 feet, temperature minus 9 degrees C, dew point minus 17 degrees C, and altimeter 30.21 inches of Hg.

The closest upper air sounding or rawinsonde (ROAB) observation was from the National Weather Service (NWS) site number 74494, located at Chatham, Massachusetts, about 8 miles southeast of the accident site. The 0700 sounding indicated a layer of low stratocumulus type clouds with bases near 1,800 feet agl with tops near 4,300 feet. The entire sounding was below freezing, even with two low-level temperature inversions. The soundings supported a chance of light to moderate icing in the stratocumulus type clouds, with the highest probability near the cloud bases.

Two pilot reports in the vicinity reported light to moderate turbulence below 4,000 feet.

Immediately prior to the accident, at 0945, the NWS Aviation Weather Center (AWC) issued their series of Airmen’s Meteorological Information (AIRMET) for the northeast and the hourly Convective Significant Meteorological Information (SIGMET) advisories. The only weather hazard identified over the area was a threat of turbulence below 8,000 feet. No large scale areas of IFR or icing conditions were identified by the NWS outside of convective activity at that time, and no Convective SIGMETs were issued for the area surrounding the period.

The NWS Current Icing Product was issued by the AWC at 1000 on the day of the accident. The chart depicted a greater than 50 percent probability of icing conditions at 2,000 feet over eastern Cape Cod and over the accident site.


The wreckage was found submerged in Cape Cod Bay, at coordinates 41 46.600 north, 70 06.996 west. Inspectors with the FAA observed the recovery of the wreckage. Once recovered, the wreckage was sent to a storage facility at Clayton, Delaware for further examination.

Examination of the wreckage did not reveal evidence of in-flight or post-crash fire and no soot was observed on the recovered wreckage. The forward cabin section contained the instrument panel area, control wheels, rudder pedals, avionics and engine controls. The firewall was present and exhibited impact damage. The engine mount was attached to the firewall and the engine was attached to the mount. All side skins and top and bottom skins were missing as were all window enclosures.

The rudder pedals were in place and the control cables were attached. The engine controls were impact-damaged and could not be moved. The pilot’s control wheel was not present and the co-pilot’s control wheel exhibited impact damage. Both rudder and stabilator trim controls and primary controls were impact-damaged and could not be operated. The cables were traced aft to their separation points. All breaks in the cables showed evidence of overstress or cuts by recovery personnel. The pilot and co-pilot seats were not located.

The primary electrical harness was in place. The circuit breakers were impact-damaged and separated from their mountings in the circuit breaker panel. Several electrical switches were impact-damaged. The pitot heat switch was found in the “on” position, as was the alternate pitot/static air source selector switch. The electrical harness was examined for pre-impact wiring integrity as were various associated components. All panel-mounted avionics were impact-damaged. The aircraft’s primary battery was not recovered. Several electrical and avionics components were removed for examination at the NTSB Materials Laboratory.

The center section of the fuselage had the left inboard wing root section attached. All top, bottom and side skins were breached. Two sets of seat belts were attached to the floor and side wall. One set had the shoulder restraint belt attached to the lap belt. The aft bench seat was located, but was not attached to the structure. The fuel valve was located and noted to be on the “right tank” position. The flap control lever was located and was impact-damaged.

The empennage was comprised of the attached vertical fin with rudder attached and the two stabilator halves. All were attached to the tail cone section in their normal positions.
The vertical fin was attached to the fuselage and exhibited leading edge impact damage and skin separation at its root areas.

The rudder was attached to the vertical fin at its hinge points. It exhibited impact damage and breaching of the skins. The balance weight was not located. Control continuity was traced forward to the aft cabin area separations, then to the forward cabin area separations. All separations exhibited overload signatures or were cut by recovery personnel.

The stabilator assembly was attached to its hinge points on the aft bulkhead. Impact damage was observed on the upper and lower surfaces. Both trim tabs were attached to the stabilator assembly and exhibited minor impact damage. The outboard 4.5 feet of each stabilator/trim tab was removed by recovery personnel. The balance weight was intact. Control cable continuity was traced forward to the forward cabin area. The trim cables were separated by recovery personnel and the trim setting was measured at 0.53 inches at the trim drum, which equated to a slight nose-up condition.

The left wing root section was attached to the fuselage. The main landing gear was damaged from impact and found in the up (retracted) position. The outboard section was breached and exhibited accordion type aft crushing of the leading edge. The fuel tank was not recovered. The upper spar cap was partially separated and bent upward approximately 45 degrees. The left aileron and its balance weight were separated. The weight was located. Aileron control continuity was established to its bellcrank. The aileron control cables were found in the instrument panel area and offered limited movement due to impact damage. The flap was segmented and partially attached.

The right wing was segmented and separated from the fuselage and had leading edge, accordion-type crushing aft. The wing skin was breached at the main fuel tank to inboard sections. The fuel tank was not recovered. The landing gear was attached and was in the up (retracted) position, with impact damage noted. The aileron was partially attached to its hinges and was bent from impact damage. Control cable continuity was established to the aileron bellcrank and then to cable separations. All separations exhibited overload signatures or were cut by recovery personnel.

The propeller hub was fractured and about 60 percent was missing. The propeller blades were not recovered.

An examination of the engine revealed that the right and left magnetos were secure and in position. When removed, both drive gears were intact. When rotated by hand, no internal binding or unusual noises were noted. There was no attempt to produce spark due to salt water and sand ingestion. The ignition wiring harness could not be tested due to impact and salt water damage.

The carburetor was broken away from the engine at its mount. A small piece of the carburetor body was recovered.

The oil pump rotated freely with no binding or unusual noises noted. No internal contamination was noted. The propeller governor drive was intact. When rotated by hand, no internal binding or unusual noises were noted.

The top spark plugs were removed for inspection. All electrodes were impacted with sand. After cleaning with water, the electrodes appeared normal in color and wear when compared to a Champion Check-A-Plug chart.

The vacuum pump was normal in appearance. The drive coupling was intact and was not sheared. The internal vanes and rotor were normal in appearance.

The numbers 2 and 4 cylinders were removed. The valves, rockers, and springs were normal in appearance. The numbers 2 and 4 pistons were removed and examined. The piston surfaces were normal appearance. No metal particulates were observed inside the oil sump. The sump contained sand. After the numbers 2 and 4 cylinders were removed, an attempt to rotate engine was made. When the propeller hub was rotated, engine continuity was established to all accessory drive gears.

The engine-driven fuel pump was removed and examined. The pump actuator was secure and there was freedom of movement. The odor of aviation fuel was evident when the pump was opened. The material between the fuel pump gaskets was extensively eroded.



The pilot reported, on his most recent FAA third class medical certificate application of December 9, 2010, the following medications: lovastatin (commercially known at Mevacor), which is a cholesterol-lowering medication used to treat elevated lipids, allopurinol (commercially known as Zyloprim), which is used to treat gout, and vitamins. During his most recent FAA examination, it was noted that the pilot was treated for elevated cholesterol with no side effects, and was treated with allopurinol for gout in remission. No other concerns were reported by the pilot and no significant issues were identified by the aviation medical examiner.

The pilot’s wife reported that he did not drink alcohol, and went to the gym for exercise. She also stated that he was working on getting off the medications he was on.

A postmortem examination of the pilot was performed at the Office of the Chief Medical Examiner, The Commonwealth of Massachusetts, on January 17, 2012. The autopsy report noted the cause of death as severe multiple injuries and the manner of death was “accident (plane crash).”

Forensic toxicology testing was performed on specimens of the pilot by the Federal Aviation Administration (FAA) Bioaeronautical Sciences Research Laboratory (CAMI), Oklahoma City, Oklahoma. The CAMI toxicology report indicated no carbon monoxide, cyanide, or ethanol in the blood. Testing of muscle specimens indicated 10 milligrams per deciliter (mg/dL) of ethanol. The CAMI report noted that the ethanol found in this case was from sources other than ingestion.

The following drugs were detected: 0.169 micrograms per milliliter (ug/ml) diazepam in the liver, 0.129 ug/ml diazepam in blood, 0.335 ug/ml nordiazepam in the liver, 0.17 ug/ml nordiazepam in blood, 1.019 ug/ml tramadol in the liver, 0.462 ug/ml tramadol in blood, and warfarin was detected in the liver and blood.

Diazepam (commercially known as Valium) is a prescription benzodiazepine derivative that has anxiolytic, sedative, muscle-relaxant, anticonvulsant, and amnestic effects. It is used to treat anxiety disorders, alcohol withdrawal, and muscle spasm. Nordiazepam is a metabolite of several different sedating benzodiazepines which are used as a treatment for anxiety. Tramadol (commercially known as Ultram) is a prescription medication that is a centrally acting sedating narcotic analgesic. The makers of this drug provide warnings that it may impair mental and/or physical ability required for the performance of potentially hazardous tasks (e.g. driving and operating heavy machinery). Warfarin (commercially known as Coumadin) is a prescription anticoagulant which acts by inhibiting vitamin K-dependent coagulation factors. The medicine is used to treat patients with deep vein thrombosis, pulmonary embolus, and atrial fibrillation.

The autopsy report noted that the blood used in the CAMI analysis was obtained from a body cavity. According to CAMI, the assessment of pilot impairment from cavity blood samples is not reliable due to concerns with postmortem redistribution of drugs.

Flight Instructor

Forensic toxicology testing was performed on specimens of the flight instructor by the Federal Aviation Administration (FAA) Bioaeronautical Sciences Research Laboratory (CAMI), Oklahoma City, Oklahoma. The CAMI toxicology report indicated no carbon monoxide, cyanide, ethanol, or drugs in the blood.


Following the wreckage examination of February 28, 2012, several components and parts from the wreckage were sent to the NTSB Materials Laboratory in Washington, DC for additional inspection. The items included a McCoy MAC 1700 comm/nav receiver, a King KNA-24 audio selector panel, two avionic cooling fans, a Davtron fuel flow indicator, an InterAv overvoltage control, a voltage regulator, power feed cables, a digital amp meter, and two 50-amp circuit breakers, including the 50-amp alternator circuit breaker, part number W23X1A1G50.

All components were x-rayed and visually examined for the presence of electrical arcing, soot, and other indicators of overheating and /or fire. There was no evidence of overheating or fire on any of the examined components.