ERA14LA346

NTSB accident investigation · Cessna 172N · Elliott Key, FL · July 20, 2014

Accident · FatalLimited investigationFinal report
Date
July 20, 2014, 14:46 local (18:46 UTC)
Place
Elliott Key, FL
Injuries
1 fatal
Damage
Destroyed
Phase of flight
Maneuvering
Aircraft
N737TPCessna 172N
Defining event
Maneuvering-low-alt flying: Abrupt maneuver
Weather
Visual (VMC) · Day
Status
Completed · report December 14, 2015
Report
Approved by Office Director
NTSB office
Eastern Region Aviation
Parties
Textron Aviation, Lycoming Engines, FAA/FSDO
FAA report
20140720024009A
Case key
89703

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

The airplane’s vertical descent into water for reasons that could not be determined because postaccident airplane examinations revealed no mechanical anomalies.

Findings · 1

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Not determinedNot determined › Not determined · Unknown/Not determinedCessna 172N: 24 casesAll aircraft: 2,247 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Abrupt maneuverManeuvering-low-alt flyingCessna 172N: 1 caseAll aircraft: 346 casesDefining event

Analysis

The student pilot departed on a local, solo instructional flight. According to the flight instructor, the student was briefed to complete three takeoffs and landings and to stay in the airport traffic pattern. Instead, the student completed one takeoff and landing and then departed the airport traffic pattern. Witnesses reported seeing the airplane in level flight about 2 hours later over the ocean 20 miles from the departure airport. Two witnesses said that the airplane's nose "pitched up" momentarily before the airplane descended vertically at "full power." One witness described the sound of the engine as "wide open" and noted that it was accelerating throughout the descent. All of the witnesses said that the airplane went "straight down" and that it did not rotate. Examination of the wreckage revealed damage consistent with a vertical descent at high speed and no preimpact mechanical anomalies. The autopsy report determined that the cause of death was "airplane crash." For the airplane to descend straight down, the forward pressure on the yoke must be increased proportionally with the increase in airspeed. If control positions remained constant, the dive would shallow out as it progressed.

Factual narrative

According to FAA and maintenance records, the airplane was manufactured in 1977. Its most recent annual inspection was completed June 4, 2014, at 18,366 aircraft hours. The airplane accrued approximately 30 hours of flight time after the inspection. According to the airplane manufacturer, the Cessna 172 had "conventional" stall characteristics, and an aural warning sounded between 5 and 10 knots above the stall. Typically, one wing will stall before the other, and the airplane will then enter a spin around the stalled wing. If the flight control positions remain unchanged, the airplane would continue in the spin, and achieve a steady-state descent. The stall and spin may be arrested by the proper flight control inputs by the pilot, or, if the flight controls were relaxed by the pilot, the spin would likely progress to a nose-down, spiraling descent. On July 20, 2014, at 1446 eastern daylight time, a Cessna 172N, N737TP, operated by Dean International Inc., was destroyed when it collided with the Atlantic Ocean following a vertical descent near Elliott Key, Florida. The student pilot was fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the flight which departed Kendall-Tamiami Executive Airport (TMB), Miami, Florida, about 1244. The solo instructional flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 141. According to the pilot's flight instructor, the purpose of the flight was for the student pilot to remain in the traffic pattern at TMB and complete 3 takeoffs and landings. The airplane was dispatched at 1140, and the school was notified of the accident by a 911 operator at 1446. According to information from the Federal Aviation Administration (FAA), the airplane took off about 1230 and remained in the traffic pattern for 15 minutes before it departed the airport traffic area. Four witnesses on the west side of Elliott Key provided statements to the police and their summaries of the events were consistent throughout. Two witnesses said their attention was drawn to the sound of the airplane's engine. They said the engine was "wide open" and at "full power" as the airplane descended vertically out of view on the west side of the key, and the sound of impact was heard. Two witnesses said the nose of the airplane "pitched up" momentarily before the airplane descended vertically at full power. In a telephone interview, one of the four witnesses said, "The airplane went straight down, steady. Like it was flying straight down. It was like he either had a heart attack, or did it deliberately. The airplane did not spiral or spin, the wings were parallel with the water the whole way down." According to another witness, the engine was "wide open. He never let off the throttle; it was running at full power." A third witness said the airplane went straight down, with no spiral or spin, and that the sound of the engine got "faster and faster, and louder and louder." He said,"The airplane appeared intact, but was going straight down. I expected him to pull up, but he never pulled up." The Miami-Dade County Medical Examiner Department, Miami, Florida, performed the autopsy on the pilot. The autopsy report listed the cause of death as "airplane crash." The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed forensic toxicology on specimens from the pilot. Ethanol was detected in the muscle and blood, but none was detected in the liver. The sample sites and quantities detected were consistent with post mortem production of ethanol. At 1458, the weather reported at Homestead Air Reserve Base (HST), 10 miles west of Elliott Key, included few clouds at 2,000 and the wind was from 090 degrees at 8 knots. The temperature was 33 degrees C, the dew point was 24 degrees C, and the altimeter setting was 30.05 inches of mercury. The pilot held a student pilot certificate with an endorsement to perform solo flight in the Cessna 172. His most recent FAA first-class medical certificate was issued on February 11, 2013. An examination of the pilot's logbook revealed that he had logged 145 total hours of flight experience, of which 105 hours were in the Cessna 172. Examination of the logbook further revealed that the pilot had logged 40 hours during the 1980's and had resumed flight training in 2013. The wreckage was recovered to and examined at Ft. Pierce, Florida, on July 25, 2014, and all major components were accounted for at examination. The engine compartment, instrument panel, cockpit, cabin area, wings and empennage were completely destroyed by impact and fragmented into very small pieces. The largest sections were the vertical fin, horizontal stabilizer, elevator and landing-gear support structure with landing gear attached. The engine was still attached to the instrument panel area by wires and cables. Control cable continuity was established from the cockpit area to the rudder and elevator. Cable continuity was traced to the ailerons through several cable and bellcrank breaks, all of which displayed failures consistent with overload. The engine was separated from the main wreckage and displayed significant impact damage. The propeller was attached, and both blades displayed similar twisting, curling, and aft bending. The starter displayed rotational scoring on its face. All engine accessories were separated by impact except the right magneto. The crankshaft was rotated by hand at the propeller flange and continuity was established through the powertrain and valvetrain to the accessory section. Thumb compression was confirmed on all cylinders using the thumb method. Neither magneto would produce spark when tested due to salt water immersion and corrosion. Disassembly revealed no visual evidence of mechanical anomaly.

Aircraft

Registration
N737TP
Reported as
Cessna 172N
Category
Airplane
Serial number
17269665
Built
1977
Airframe hours
18,366
Engine
Lycoming O-360 SERIES, 160 horsepower, reciprocating
Damage
Destroyed
Flight
Instructional · Part 91
Operator
Dean International Inc
Registered owner
Lily Aviation Corp
Airworthiness certificate
Standard, Utility; Standard, Normal
Last inspection
Annual · June 4, 2014 · 86 hours before
Departed
TMB · Miami, FL
Destination
TMB · Miami, FL
Equipment
Stall warning system

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
51
Injuries
Fatal
Certificate
Student
Airplane ratings
Single-engine land
Medical
Class 1, With waivers/limitations
Seat
Left
Toxicology
Performed
Flight hours
145 total · 105 in this make and model · 3.9 as pilot in command · 10.8 in the last 90 days · 2.7 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
90° at 8 knots
Visibility
10 statute miles
Temperature
91 °F, dew point 75 °F
Altimeter
30.04 inHg
Observed at
HST, 12 nm away

Docket · 10

The files NTSB released with the investigation on November 10, 2015, on NTSB’s docket system: statements, records, photos and specialists’ reports. 9.6 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.