# NTSB ANC10LA065: Cessna 170B, N4590C, Palmer, AK, July 23, 2010 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: July 22, 2010, 20:00 local (Jul 23, 2010, 04:00 UTC) - Place: Palmer, AK - Coordinates: 61.617778, -148.554992 - Nearby events: https://openairdocs.org/map.md?lat=61.6178&lon=-148.5550&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed, report April 7, 2011 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: AFF FSDO-03 - NTSB case key (mKey): 76734 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC10LA065 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/76734/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=76734 - Page: https://openairdocs.org/ntsb/ANC10LA065 ## 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 NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: climb rate](https://openairdocs.org/ntsb-findings/01062035): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Cessna 170B, 6 cases](https://openairdocs.org/ntsb-findings/01062035/cases.md?model=2072306), [All aircraft, 265 cases](https://openairdocs.org/ntsb-findings/01062035/cases.md) - [Knowledge: knowledge of meteorologic cond](https://openairdocs.org/ntsb-findings/02032020): Personnel issues › Experience/knowledge · Pilot (probable cause); cases with it: [Cessna 170B, 1 case](https://openairdocs.org/ntsb-findings/02032020/cases.md?model=2072306), [All aircraft, 30 cases](https://openairdocs.org/ntsb-findings/02032020/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Cessna 170B, 15 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2072306), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Contributed to outcome; cases with it: [Cessna 170B, 2 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=2072306), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Cessna 170B, 1 case](https://openairdocs.org/ntsb-events/220/sequence.md?model=2072306), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) ## 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](https://openairdocs.org/deregistered/N4590C-2019-01-31), registration cancelled 2019-01-31, S/N 25534 (OpenAirDocs) - Reported make and model: CESSNA 170B - Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs) - Category: Airplane - Serial number: 25534 - Airframe hours: 6322 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; injuries: minor; 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 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20100722041159A](https://openairdocs.org/incident/20100722041159A), Jul 22, 2010: Cessna 170B, Palmer, AK, Substantial damage. The pilot stated that he spotted a back country airstrip and wanted to make some approaches without landing. On initiating a go around as he had planed, the… ## Other investigations on N4590C (3) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB LAX00LA340](https://openairdocs.org/ntsb/LAX00LA340), Sep 16, 2000: Cessna 170B (N4590C), Alturus, CA, substantial damage. Probable cause: The pilot's inadequate compensation for the wind, and his failure to maintain directional control of the airplane during landing. A factor was the faded improperly maintained windsock. - [NTSB SEA97LA053](https://openairdocs.org/ntsb/SEA97LA053), Jan 26, 1997: Cessna 170B (N4590C), Toledo, WA, substantial damage. Probable cause: The pilot's excessive application of the brakes on a tailwheel equipped aircraft. Factors include the pilot's inadequate compensation for wind conditions, and a crosswind blowing at the time of the… - [NTSB SEA73DYE36](https://openairdocs.org/ntsb/SEA73DYE36), May 26, 1973: Cessna 170B (N4590C), Auburn, WA, substantial damage ## Docket (1 files) The files NTSB released with the investigation on November 5, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=76734. 605 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 605 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40338852&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.