NTSB Factual Report

HISTORY OF FLIGHT

On June 10, 2016, at 1710 Pacific daylight time, a Grumman American Aviation Corporation AA-1B, N4SU, was destroyed when it impacted a residence shortly after takeoff from Jack Northrop Field/Hawthorne Municipal Airport (HHR), Hawthorne, California. The private pilot and flight instructor were fatally injured. There were no ground injuries. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the instructional flight, and no flight plan was filed.

A mechanic at a fixed-base operator (FBO) at HHR stated that the pilot and the instructor met in the lobby of the FBO before proceeding to the airplane about 10 minutes later. He stated that the flight was part of a flight review. The mechanic stated that he was not familiar with the instructor and that the pilot typically flew alone. He observed the airplane take off and stated that he "knew something was wrong" when the airplane was about 3/4 of the way down the runway during the takeoff roll. As it neared the departure end of the runway, the airplane was "about at the roofline" of the surrounding buildings and in a nose-up attitude. He stated that the engine sounded "smooth" but like it was "at half power."

The tower controllers at HHR reported that the pilot phoned the tower to arrange for a no-radio departure using light gun signals. During this conversation, the pilot said that he had obtained the current automated weather information. The airplane taxied to runway 25, was issued a green light gun signal, and subsequently departed. The controllers observed the airplane become airborne, settle back onto the runway about 1,500 ft from its initial rotation point, and then become airborne again. The controllers stated that the airplane "remained low" as it climbed out.

A commercial pilot who was preparing to start his airplane at HHR stated that his attention was drawn to the accident airplane due to the "rough" sound of its engine, and he stated that its climb rate was "much lower" than that of a typical airplane on departure. He estimated its altitude at the departure end of the runway to be between 400 and 500 ft above the ground. He stated that the pilot appeared to be "trying to gain altitude by lowering the nose to gain airspeed and pitching up"; however, each time the airplane's nose rose, the airplane lost altitude. He then saw the airplane "steering around some palm trees to avoid a collision" before it disappeared from his view below trees and buildings.

PERSONNEL INFORMATION

The pilot, age 90, was the owner of the airplane. He held a private pilot certificate with ratings for airplane single- and multi-engine land, instrument airplane, and glider. His most recent Federal Aviation Administration (FAA) third-class medical certificate was issued on August 19, 2015, with a limitation for corrective lenses, and was not valid for any class after August 31, 2016. On the application for that certificate, the pilot reported 3,000 total hours of flight experience, of which 50 hours was flown in the previous 6 months.

The instructor, age 71, held an airline transport pilot certificate with ratings for airplane single- and multi-engine land, and a flight instructor certificate with a rating for airplane single-engine. His most recent FAA third-class medical certificate was issued in May 2016 with a limitation for corrective lenses. On the application for that certificate, he reported 18,000 total hours of flight experience, with 200 hours in the previous 6 months.

Personal flight logs were not recovered for either pilot.

AIRCRAFT INFORMATION

The airplane was manufactured in 1974 and registered to the pilot in December 2015. It was equipped with a 108-horsepower (hp) Lycoming O-235-C2C reciprocating engine. In June 2005, the airplane was equipped with a new propeller in accordance with a supplemental type certificate, which increased the engine power rating from 108 hp to 115 hp. The most recent annual inspection was completed in November 2015 at 1,724 hours total airframe time. At the time of the annual inspection, the engine had accumulated 1,724 hours since new and 611.6 hours since top overhaul. (At an unspecified time in 2001, the engine received 4 new cylinders, commonly referred to as a top overhaul.) The maintenance logbooks indicated that the airplane had accumulated about 39 hours of operation in the 26 months before this annual inspection. The airframe and engine times at the time of the accident could not be determined.

According to the maintenance logbooks, the engine had never been overhauled.

The total fuel on board the airplane at the time of the accident could not be determined. If the airplane had been fueled to capacity (24 gallons) before the flight, it would have been operating about 20 lbs under its maximum certificated gross weight of 1,560 lbs. At maximum gross weight, given the atmospheric conditions present at the time of the accident, the airplane's takeoff ground run distance would have been about 850 ft; its distance to clear a 50-ft obstacle would have been about 1,700 ft.

METEOROLOGICAL INFORMATION

The 1653 weather observation at HHR included wind from 270° at 8 knots, clear skies, 10 miles visibility, temperature 22°C, dew point 4°C, and an altimeter setting of 29.89 inches of mercury.

AIRPORT INFORMATION

The airport was located in a densely-populated suburb of Los Angeles. The area surrounding the airport comprised both residential and business developments.

WRECKAGE AND IMPACT INFORMATION

The airplane impacted a residence about 1 nautical mile west of HHR. The initial impact point was identified as an approximate 30-ft-tall palm tree about 40 ft east of the residence. The majority of the airplane's left wing came to rest under the tree and exhibited a concave depression consistent with the diameter of the tree. The main wreckage came to rest against the front of the residence and was consumed by postcrash fire. The empennage was suspended from the second-floor balcony, and the control cables remained attached to the main wreckage. Flight control continuity was established from the cockpit area to the rudder and elevator; however, continuity to the ailerons could not be established due to fire damage. The wing spar was fractured in several locations. No information could be obtained from the cockpit instruments.

The propeller remained attached to the engine at the crankshaft flange, and the engine remained attached to its mounts. One propeller blade exhibited slight s-bending and chordwise scratching; the second blade was relatively undamaged.

The engine was rotated by hand, and continuity of the valve and drivetrain was confirmed. Thumb compression was obtained on all cylinders. The carburetor was separated from the engine and sustained thermal damage. The float bowl was absent of fuel, and both metal floats were damaged. The magnetos and engine-driven fuel pump were significantly fire damaged and could not be tested further. The spark plugs were removed and displayed normal wear.

Disassembly and detailed examination of the engine's internal components revealed that the crankshaft was undamaged; however, all of the bearings displayed radial scoring. The tappet faces corresponding to the intake valves of all 4 cylinders displayed spalling, and the corresponding camshaft lobes were significantly worn. When measured with a caliper, the camshaft lobes corresponding to all 4 exhaust valves measured 1.400 inches. The lobe corresponding to the Nos. 1 and 2 cylinder intakes measured 1.275 inches, and the lobe corresponding to the Nos. 3 and 4 cylinder intakes measured 1.250 inches.

MEDICAL AND PATHOLOGICAL INFORMATION

Pilot

The County of Los Angeles, Department of Medical Examiner–Coroner, Los Angeles, California, performed an autopsy on the pilot. The cause of death was multiple blunt injuries, and the manner of death was accident. Contributing to the death was atherosclerotic cardiovascular disease. Examination of the body for natural disease was limited by the severity of the pilot's injuries. The heart weighed 660 grams and showed biventricular enlargement (average for a 190-lb man is 362 grams with a range of 275-478 grams). The left ventricular wall and septum were thickened at 2.2 cm, and the right ventricular wall was thickened at 0.7 cm (averages are 1.23 cm for the left wall and septum and 0.3 cm for the right wall). The native coronary arteries were severely stenosed at 80% for the left anterior descending and 90% for the right and circumflex coronary arteries.

The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing of specimens from the pilot. Losartan was identified in lung tissue, urine, and cavity blood; metoprolol was identified in urine and blood; and sitagliptin was identified in lung tissue, urine, and cavity blood. Losartan and metoprolol are prescription medications used for the treatment of high blood pressure. Sitagliptin is a prescription medication used to treat diabetes. None of these medications are considered impairing.

Instructor

The County of Los Angeles, Department of Medical Examiner–Coroner, Los Angeles, California, performed an autopsy on the instructor. The cause of death was flame burn injury and multiple blunt force injuries, and the manner of death was accident. The heart was described as severely enlarged and dilated. It weighed 500 grams; the average for a 163-lb man is 336 grams with a range of 255 to 444 grams. The left ventricle and septum were 1.6 cm thick, and the right ventricle was 0.3 cm thick. The autopsy noted sternotomy wires from a previous procedure, along with scarring of the pericardium, but the report did not describe the degree of stenosis in the left anterior descending coronary artery or the presence/patency of the graft from the left internal mammary artery. The report did describe extensive atherosclerosis with 80% stenosis of the right coronary artery and 30% stenosis of the circumflex branch of the left coronary artery. The absence of the right kidney was also noted.

The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing of specimens from the instructor. Atvorastatin was identified in liver; cetirizine, hydroxyzine, and warfarin were identified in liver, lung, and muscle; and 0.063 ug/mL of tramadol was identified in blood. Atvorastatin, also called Lipitor, is a prescription medication for the treatment of high cholesterol, and it is not considered impairing. Cetirizine, often sold as Zyrtec, is a potentially-sedating antihistamine available over the counter and by prescription. It carries the warning, "when using this product, drowsiness may occur; alcohol, sedatives, and tranquilizers may increase drowsiness; avoid alcoholic drinks; be careful when driving a motor vehicle or operating machinery." Hyroxyzine is a sedating antihistamine available by prescription and often sold with the names Atarax and Vistaril. Its warning states, "since drowsiness may occur with use of this drug, patients should be warned of this possibility and cautioned against driving a car or operating dangerous machinery while taking hydroxyzine. Patients should also be advised against the simultaneous use of other [central nervous system] suppressant drugs and cautioned that the effects of alcohol may be increased." Tramadol is prescription opioid available as a Schedule IV controlled substance and used to treat pain. It increases the risk of seizures via an unknown mechanism, even when used at usual doses. Tramadol can be sedating and "should be used with caution and in reduced dosages when administered to patients receiving other central nervous system depressants such as alcohol, opioids, anesthetic agents, narcotics, phenothiazines, tranquilizers, or sedative hypnotics. Tramadol hydrochloride increases the risk of CNS and respiratory depression in these patients."

According to the instructor's personal medical records, he developed kidney failure and began dialysis in 2012. In early 2013, he developed severe coronary artery disease, which required a coronary artery bypass graft procedure in January 2013. Also in 2013, he had the laparoscopic removal of an ileal mass, underwent hernia surgery, and had a cancerous right kidney removed. All these procedures were complicated by paroxysmal atrial fibrillation. By 2015, he was chronically in atrial fibrillation and was taking warfarin (a blood thinner) for anticoagulation. In addition to his hypertension, he had chronic low back pain, post-traumatic stress disorder, an anxiety disorder, and restless leg syndrome. The pilot did not report these conditions to the FAA. On the day before the accident, the instructor checked in with his pharmacist regarding his medications. Among his 18 active, daily home medication prescriptions were acetaminophen, methocarbamol, lidocaine/prilocaine cream, and tramadol for pain; omeprazole for heartburn; aspirin to prevent heart attack; carvedilol and losartan for blood pressure; atorvastatin for cholesterol; loratadine and hydroxyzine for chronic itching; pramipexole for restless leg syndrome; sertraline for depression; and warfarin to thin his blood. Of these medications, methocarbamol, tramadol, pramipexole, and sertraline are either potentially impairing or indicate a potentially-impairing condition.

ADDITIONAL INFORMATION

According to Lycoming Service Instruction SI1009AZ, "Recommended Time Between Overhaul Periods," the make/model engine installed on the airplane should be overhauled at 2,000-hour intervals or before the 12th year, whichever occurs first. The instruction further states:

Engine deterioration in the form of corrosion (rust) and the drying out and hardening of composition materials such as gaskets, seals, flexible hoses and fuel pump diaphragms can occur if an engine is out of service for an extended period of time. Due to loss of a protective oil film after an extended period of inactivity, abnormal wear on soft metal bearing surfaces can occur during engine start.

Lycoming Service Letter L180B, "Engine Preservation for Active and Stored Aircraft," states that, "Engines in aircraft that are flown only occasionally may not achieve normal service life because of corrosion. This occurs when moisture from the air and products of combustion combine to attack cylinder walls and bearing surfaces during periods when the aircraft is not used."

NTSB Probable Cause

The failure of both pilots to land the airplane on the remaining runway when a sufficient rate of climb could not be attained. Contributing to the accident was a reduction of available engine power due to severe camshaft lobe wear.