# NTSB DFW08TA225: Diamond Aircraft Industries DA-20-C-1, N939DA, Pueblo, CO, September 8, 2008 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Final report - Date: September 8, 2008, 11:47 local (17:47 UTC) - Place: Pueblo, CO - Coordinates: 38.289886, -104.540771 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.2899&lon=-104.5408&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Aircraft wake turb encounter](https://openairdocs.org/ntsb-events/361) - Highest injury: Serious injuries - Injuries: 2 serious - Status: Completed, report March 5, 2009 - Report: Approved by Office Director - Parties: United States Air Force, Diamond Aircraft Industries, Doss Aviation, FAA FSDO, Teledyne Continental Motors - NTSB case key (mKey): 68892 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW08TA225 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68892/pdf - Page: https://openairdocs.org/ntsb/DFW08TA225 ## Probable cause The student pilot's inability to maintain aircraft control due to an encounter with wake turbulence from a preceding larger aircraft. Contributing to the accident was the instructor pilot's failure to intervene. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Diamond Aircraft Ind DA20-C1, 5 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=2990001), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) - [Turbulence: wake turbulence](https://openairdocs.org/ntsb-findings/03032025): Environmental issues › Conditions/weather/phenomena · Ability to respond/compensate (probable cause); cases with it: [Diamond Aircraft Ind DA20-C1, 2 cases](https://openairdocs.org/ntsb-findings/03032025/cases.md?model=2990001), [All aircraft, 47 cases](https://openairdocs.org/ntsb-findings/03032025/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Student/instructed pilot (probable cause); cases with it: [Diamond Aircraft Ind DA20-C1, 37 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2990001), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Diamond Aircraft Ind DA20-C1, 6 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md?model=2990001), [All aircraft, 792 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern final: Aircraft wake turb encounter](https://openairdocs.org/ntsb-events/361) (defining event); cases with it: [Diamond Aircraft Ind DA20-C1, 1 case](https://openairdocs.org/ntsb-events/361/sequence.md?model=2990001), [All aircraft, 37 cases](https://openairdocs.org/ntsb-events/361/sequence.md) - [Approach-VFR pattern final: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Diamond Aircraft Ind DA20-C1, 16 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=2990001), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Diamond Aircraft Ind DA20-C1, 32 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2990001), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis According to the flight instructor and student pilot, while maneuvering to land, the accident airplane encountered wake turbulence from a preceding C-130 airplane. The accident airplane then began an uncommanded pitch, roll, and descent that could not be arrested prior to an impact with terrain. A review of radar data revealed that the flight path of the accident airplane was in an area favorable for a wake vortex encounter. No anomalies were reported by the flight instructor and student pilot or noted during the postaccident examination of the airframe and engine. ## Factual narrative On September 8, 2008, at approximately 1147 mountain daylight time, a single-engine Diamond DA-20-C-1 airplane, N939DA, was substantially damaged upon impact with terrain near Pueblo Memorial Airport (PUB), Pueblo, Colorado. The flight instructor and student pilot were seriously injured. The airplane was owned by Doss Aviation Incorporated and operated under contract by the United States Air Force (USAF). The airplane departed PUB for the local instructional flight. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 91 public use flight. According to the flight instructor and student pilot, while entering the pattern for runway 8L's overhead pattern, they were informed by the tower controller to follow a C-130 and to be cautious of wake turbulence. With direction from the flight instructor, the student pilot turned and entered the downwind leg. The flight instructor recalled seeing the C-130 on a wide pattern and elected to lengthen the downwind leg and began to turn to final approximately 1 nautical mile past the runway threshold. Both pilots recalled that engine and airspeed parameters appeared "normal." Once the airplane was level on final, the student pilot was attempting to "keep it high," but noted that the glide slope indicators displayed "2 red/2 white." Furthermore, the student pilot reported that at approximately 1/2 mile from the threshold, the airplane encountered wake turbulence from the preceding C-130. The airplane began an uncommanded pitch up, rolled left and then began descending. Full throttle and opposite flight controls were applied. Despite attempts to regain level flight by both the student pilot and the flight instructor, the airplane descended until it collided with terrain. An examination of the airframe and engine was conducted by the NTSB with technical assistance from representatives of Diamond Aircraft and Teledyne Continental Motors. Flight control continuity was established to the ailerons, elevators, and rudder. The flaps were set to the landing position. No anomalies were noted which would have precluded the safe operation of the airplane. Engine valve train continuity, accessory gear continuity, compression and suction were established. The fuel manifold contained traces of fuel, and the fuel screen was found clear of debris. Both magnetos produced spark at all terminals. The throttle was found at the approximate full throttle position and the mixture control was found near the full rich position. The fuel inlet screen and oil filter were clear of debris. No anomalies were noted which would have precluded the production of engine power. A review of tower radar returns revealed that the accident airplane flew 56 to 62 seconds behind and within 1/4 to 1/2 nautical miles downwind of the preceding C-130's flight path. Federal Aviation Administration Advisory Circular 90-23F, Aircraft Wake Turbulence released February 20, 2002, "is intended to alert pilots to the hazards ofaircraft wake turbulence and recommends related operational procedures." Under the heading of "6. Induced Roll" the circular stated that "...the capability of an aircraft to counteract the roll imposed by the wake vortex primarily depends on the wingspan and counter-control responsiveness of the encountering aircraft." An 1153, an automated weather reporting facility at PUB, reported winds from 120 degrees at 7 knots, visibility 10 miles, ceiling broken at 2,500 feet, overcast at 3,900 feet, temperature 54 degrees Fahrenheit, dew point 39 degrees Fahrenheit, and a barometric pressure of 30.30 inches of Mercury. ## Aircraft - Registration: [N939DA](https://openairdocs.org/deregistered/N939DA-2011-06-09), registration cancelled 2011-06-09, S/N C0505, built 2008 (OpenAirDocs) - Reported make and model: Diamond Aircraft Industries DA-20-C-1 - Registry model: [Diamond Aircraft Ind DA20-C1](https://openairdocs.org/model/diamond-aircraft-ind-da20-c1) (registry code 2990001) (OpenAirDocs) - Registry engine: [Continental IO-240-B](https://openairdocs.org/engine/continental-io-240-b) (registry code 17177, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: C0505 - Airframe hours: 88.7 - Engines: Teledyne Continental IO-240 125 horsepower reciprocating - Damage: Substantial damage - Flight: Public aircraft, Part 91 - Operator: Doss Aviation Inc - Registered owner: Doss Aviation Inc - Airworthiness certificate: Standard, Utility - Last inspection: Continuous airworthiness, August 1, 2008, 39.3 hours before - Departed: PUB, PUEBLO, CO - Flight plan: Company VFR - Airport: PUB, Pueblo Memorial, runway 08L, 10,496 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 25; injuries: serious; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; seat: left; flight hours: 1,025 total, 288 in this make and model, 915 as pilot in command - Student pilot; age 23; injuries: serious; student; medical: class 3, without waivers/limitations; seat: right; flight hours: 6 total, 6 in this make and model, 6 in the last 90 days, 6 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: 3,900 ft overcast - Temperature: 54 °F, dew point 39 °F - Altimeter: 30.29 inHg - Observed at: PUB ## 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 20080908845989A](https://openairdocs.org/incident/20080908845989A), Sep 8, 2008: Diamon DA20C1, Pueblo, CO, Destroyed. (-23) On 8 September 2008, diamond DA-20-C1, registration N939DA, serial number C0505, crashed 1/4 mile west on approach end of runway 08L, (kpub). Aircraft… 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.