ANC10LA065

NTSB accident investigation · Cessna 170B · Palmer, AK · July 23, 2010

Accident · Serious injuriesLimited investigationFinal report
Date
July 22, 2010, 20:00 local (Jul 23, 2010, 04:00 UTC)
Place
Palmer, AK
Injuries
1 serious, 1 minor
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N4590CCessna 170B
Defining event
Maneuvering-low-alt flying: Low altitude operation/event
Weather
Visual (VMC) · Day
Status
Completed · report April 7, 2011
Report
Approved by Office Director
NTSB office
Alaska Regional Office
Parties
AFF FSDO-03
FAA report
20100722041159A
Case key
76734

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 pilot's decision to make a low-altitude pass over a remote airstrip toward rising terrain in weather conducive to downdrafts.

Findings · 4

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.

Performance/control parameters: climb rateAircraft › Aircraft oper/perf/capability · Not attained/maintainedCessna 170B: 6 casesAll aircraft: 265 casesProbable cause
Knowledge: knowledge of meteorologic condPersonnel issues › Experience/knowledge · PilotCessna 170B: 1 caseAll aircraft: 30 casesProbable cause
Wind: downdraftEnvironmental issues › Conditions/weather/phenomena · Contributed to outcomeCessna 170B: 2 casesAll aircraft: 178 cases

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.

Analysis

The pilot stated that he was maneuvering the airplane following a creek and observed an airstrip below. He decided he would make a practice approach to the airstrip, with no intention of landing. On the second approach, upon reaching the threshold of the landing area, he initiated a climb. After flying the length of the airstrip, the airplane started to descend. The pilot opined that the airplane had entered a downdraft and in response applied full engine power. The airplane continued to descend and collided with rising terrain near the end of the airstrip. The airplane sustained structural damage to its wings and fuselage. The airplane was equipped with a required emergency locator transmitter (ELT), however, it was an older generation ELT that transmitted only on 121.5 megahertz, not the newer, digital version that transmits on 406 megahertz. As of February 2009, the search and rescue satellites that receive ELT signals no longer had the capability to receive the older analog 121.5 megahertz ELTs. The 406 megahertz ELTs are received within seconds of activation, and rescuers are notified within minutes of the accident location. In this accident, the pilot and passenger were missing for 2 days and a search was initiated. They were able to walk to a trail, despite serious injuries, where a group of all terrain vehicle riders assisted them.

Factual narrative

On July 22, 2010, about 2000 Alaska daylight time, a tailwheel-equipped Cessna 170B airplane, N4590C, sustained substantial damage when it collided with terrain, about 18 miles northeast of Palmer, Alaska. The airplane was being operated by the pilot as a visual flight rules personal local flight under the provisions of Title 14, CFR Part 91. The private pilot received serious injuries, and the sole passenger received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed. The flight departed the Palmer Airport, about 1830. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on July 27, the pilot said he and the passenger were on a local sightseeing flight. He said he flew up a creek he had not flown up before. The pilot reported seeing an airstrip, and decided he would make a practice approach to it, but had no intentions of landing. He said upon reaching the threshold of the airstrip, he initiated a positive rate of climb, but after flying along the length of the landing area the airplane started to descend. The pilot said he thought they had entered a downdraft, and he applied full power. He said the airplane continued to descend, and he checked the engine controls to make sure they were in a climb configuration, which they were. The pilot said they had made the pass over the airstrip with 20 degrees of flaps, and when it was apparent he couldn't arrest the descent, he added full flaps to slow the airplane and cushion the impact. The airplane collided with rising terrain near the end of the airstrip, and sustained substantial damage to the wings and fuselage. In a written report dated July 27, the pilot reported that proficiency in recognizing potential weather hazards, and greater situational awareness overall, might have helped prevent the accident. The airplane was equipped with a required emergency locator transmitter (ELT), however, it was an older generation ELT that transmitted on 121.5 megahertz, not the newer, digital version that transmits on 406 megahertz. As of February 1, 2009, the search and rescue satellites that receive ELT signals no longer had the capability to receive the older analog 121.5 megahertz ELTs. The 406 megahertz ELTs are received within seconds of activation, and rescuers are notified within minutes of the accident location. In this accident, the pilot and passenger were missing for 2 days, but were able to walk to a trail, despite serious injuries, where a group of all terrain vehicle riders assisted them.

Aircraft

Registration
N4590C
Reported as
Cessna 170B
Category
Airplane
Serial number
25534
Airframe hours
6,322
Engine
Teledyn Continental C-145, 145 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Operator
Akers David W
Registered owner
Akers David W
Airworthiness certificate
Standard, Normal
Last inspection
Annual · April 23, 2010
Departed
PAAQ · Palmer, AK
Destination
PAAQ · Palmer, AK

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
Minor
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 2, Without waivers/limitations
Last flight review
September 21, 2009
Seat
Left
Flight hours
537 total · 179 in this make and model · 485 as pilot in command · 78 in the last 90 days · 24 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Visibility
15 statute miles
Temperature
45 °F

Docket · 1

The files NTSB released with the investigation on November 5, 2010, on NTSB’s docket system: statements, records, photos and specialists’ reports. 605 KB 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.

Other investigations on N4590C · 3

Matched to the same aircraft by N-number and date.