Cessna 150L N1539Q

Summary

On 14 July 2011 at about 13:30 local time, a Cessna 150L registered N1539Q was involved in an accident near Silverton, Colorado, United States. 2 people were on board and 2 died. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

14 July 2011 at 13:30

Classification

Accident

Location

Silverton, Colorado, United States

Coordinates

37.7908, -107.5503

Aircraft

Cessna 150L

Registration

N1539Q

Category

Airplane

Year built

1971

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Durango → Durango

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN11FA479

2 people died.

The pilot's failure to maintain control of the airplane while operating it at low levels above mountainous terrain and in excess of its maximum allowable gross weight, which resulted in an aerodynamic stall. The pilot's failure to maintain control resulted from an acute cardiac event and incapacitation, hypoxia, or the effects of sedating medications or a combination of these factors. Contributing to the accident was the pilot's improper decision to takeoff above gross weight and without oxygen for the flight in mountainous terrain.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

A witness saw the airplane flying low over mountainous terrain. He then saw the nose of airplane pull up, followed by the airplane flying inverted and departing controlled flight; the airplane's observed behavior is indicative of an aerodynamic stall. The airplane impacted rocky terrain at 12,570 feet mean sea level. The airplane was operating in excess of its maximum allowable gross weight. Further, the pilot was not using supplemental oxygen, despite a risk for hypoxia above 10,000 feet. The postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The pilot's autopsy indicated moderate to severe diffuse coronary artery disease. This elevated his risk for acute coronary syndrome or an acute arrhythmia followed by incapacitation but would have left no evidence at autopsy. Further, hypoxia would have increased the likelihood of an acute cardiac event. Additionally, the pilot had significant levels of multiple impairing medications at the time of the crash that would have affected his ability to operate the airplane. The pilot was very likely impaired by this combination of sedating medications, even at levels that were probably therapeutic. Further, the medications would have affected his decision-making ability, which may have played a role in his decision to fly at these altitudes without oxygen and above the airplane's maximum gross weight.

Quoted verbatim from the NTSB record.