# NTSB WPR17LA030: Aero Commander 690, N9175N, Scottsdale, AZ, December 1, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: November 30, 2016, 17:30 local (Dec 1, 2016, 00:30 UTC) - Place: Scottsdale, AZ - Coordinates: 33.613609, -111.921386 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.6136&lon=-111.9214&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 14, 2020 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA-FSDO - NTSB case key (mKey): 94462 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR17LA030 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/94462/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=94462 - Page: https://openairdocs.org/ntsb/WPR17LA030 ## Probable cause The pilot’s loss of directional control during the landing roll, which resulted in the runway excursion onto the rock-covered runway safety area. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Aero Commander 690, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=0141720), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Aero Commander 690, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=0141720), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Object/animal/substance: debris/dirt/foreign object](https://openairdocs.org/ntsb-findings/03022055): Environmental issues › Physical environment · Effect on equipment (probable cause); cases with it: [Aero Commander 690, 1 case](https://openairdocs.org/ntsb-findings/03022055/cases.md?model=0141720), [All aircraft, 101 cases](https://openairdocs.org/ntsb-findings/03022055/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Aero Commander 690, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=0141720), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Aero Commander 690, 1 case](https://openairdocs.org/ntsb-events/300/sequence.md?model=0141720), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot reported that, during the landing roll, he commanded reverse thrust and lightly applied brake pressure. While he was reaching for the condition levers to bring the propellers back to low rpm, the airplane suddenly veered to the right. The pilot applied left braking action and adjusted the engines to low rpm, but the airplane continued to veer toward the right side of the runway and a runway sign. The pilot reported that he could have either gotten more aggressive with the corrective actions and hope to avoid striking the sign, or allow the airplane to exit the runway onto what he thought was a hard, smooth surface. The pilot chose to exit the runway surface, and the airplane entered the runway safety area, which had a rock layer that consisted of river rock. The landing gear sunk deep into the rocks, which quickly slowed the airplane to a stop. Several rocks penetrated the fuselage, which resulted in substantial damage. A postaccident examination of the steering and brake system revealed no evidence of a mechanical failure or malfunction that would have precluded normal operation. ## Factual narrative On November 30, 2016, about 1730 mountain standard time, an Aero Commander 690, N9175N, was substantially damaged when it was involved in an accident at the Scottsdale Airport (SDL), Scottsdale, Arizona. The commercial pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 maintenance relocation flight. The pilot reported that after a normal landing on runway 21 he began easing the power levers into reverse and applying light braking action to slow the speed. While reaching for the condition levers to bring the propellers back to low RPM, the airplane "darted to the right." The pilot applied left braking and adjusted the engines to low RPM settings to compensate for the veer. Despite his actions, the airplane continued to veer towards the right side of the runway and was approaching the A11 exit sign. The pilot reported that he could have either gotten more aggressive with the corrective actions, and hope to avoid striking the sign, or allow the airplane to exit the runway on what he thought was a hard smooth surface. The pilot chose to exit the runway surface which was the runway safety area (RSA). Once the airplane entered the RSA, the landing gear sunk deep into the rocks which quickly slowed the airplane to a stop. Security cameras captured the airplane during landing. The airplane touched down near the 1,000 ft runway distance markers and about 1,300 ft further, exited near taxiway A11. The airplane traveled about 50 ft into the RSA, creating deep troughs through the rock layer, and came to a stop about 2,500 ft from the approach end of runway 1. A postaccident examination of the airplane revealed impact damage to the left side of the fuselage. The impact damage consisted of multiple holes and dents in the fuselage cabin passenger area and window areas. A rock about 2 inches in length was found imbedded in the fuselage and could not be removed during the examination. Several rocks penetrated the passenger area, one impacting the right side window from the inside. The propeller blades had gouging on the leading edges from the midsections to the tips. The right landing gear brake rotor showed light gouging on the braking surface. The flight control system was examined, and all flight controls moved freely with unobstructed movement. The steering system was operated with the activation of the hydraulic system and the nose landing gear tire was positioned over a grease plate. Actuation of the brakes produced normal steering operation. No evidence of any mechanical malfunctions or failures were revealed that would have precluded normal operation. The RSA rock layer consisted of about 3-inch sized smoothed river rock. The depth of the rock layer varied from 4-inches to 12-inches deep through the area of the accident site. Accident Site and Runway Tire Marks According to the FAA, RSAs are not designed with a particular aircraft in mind. RSA's are designed to provide all aircraft types with the space andtime needed to safely come to a stop while avoiding fixed obstacles on the airport that may damage the aircraft and potentially injure or kill the occupants. RSAs are designed to support the aircraft without sinking into the soil and causing an abrupt halt. RSAs can be made of many materials, including rocks. These rocks should be no larger than four inches in size. RSAs, like any other landing/runway ground surface, are not designed for contact by any part of the aircraft other than the landing gear. The design of an RSA does not take into consideration contact by propellers, engines, wings, etc. RSAs around the country have proven to be effective at mitigating damage, injury, and death when runway excursions and overruns occur. According to the Department of Transportation Advisory Circular (AC 150/5300-13A)- An RSA is defined as a surface surrounding the runway prepared or suitable for reducing the risk of damage to aircraft in the event of an undershoot, overshoot, or excursion from the runway. Also, FAA Order 5200.8, defines that RSA is intended to provide a measure of safety in the event of an aircraft's excursion from the runway by significantly reducing the extent of personal injury and aircraft damage during overruns, undershoots and veer-offs. SDL RSA design and specification drawings show a crushed aggregate depth of 4 inches. ## Aircraft - Registration: [N9175N](https://openairdocs.org/deregistered/N9175N-2019-10-05), registration cancelled 2019-10-05, S/N 11071, built 1973 (OpenAirDocs) - Reported make and model: AERO COMMANDER 690 (UNDESIGNAT) - Registry model: [Aero Commander 690](https://openairdocs.org/model/aero-commander-690) (registry code 0141720) (OpenAirDocs) - Registry engine: [AiResearch TPE331 series](https://openairdocs.org/engine/airesearch-tpe331-series) (registry code 01514, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 11071 - Year built: 1973 - Engines: Honeywell TPE 331-5 715 horsepower turbo prop; Honeywell TPE 331-5 715 horsepower turbo prop - Damage: Substantial damage - Flight: Positioning, Part 91 - Operator: Air West Inc - Registered owner: Air West Inc - Airworthiness certificate: Standard, Normal - Departed: SAD, SAFFORD, AZ - Destination: SDL, SCOTTSDALE, AZ - Flight plan: Company VFR - Airport: SDL, Scottsdale, runway 21, 8,249 × 100 ft, asphalt - Equipment: Stall warning system, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; seat: left; restraint: 4-point; flight hours: 4,654 total, 322 in this make and model, 4,654 as pilot in command, 21 in the last 90 days ## Weather - Conditions: Visual (VMC), Dusk - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 18 °F - Altimeter: 29.98 inHg - Observed at: KSDL, 1 nm away ## 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 20161130018859A](https://openairdocs.org/incident/20161130018859A), Nov 30, 2016: Aero Commander 690, Scottsdale, AZ, Substantial damage. Aircraft landed runway 21 and aircraft veered right going into an area called the runway safety area (rsa). The pilot had both engines in beta when the… ## Docket (5 files) The files NTSB released with the investigation on July 8, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=94462. 4.8 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485167&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Pilot Statement (item 2, .PDF, 338 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485168&FileExtension=.PDF&FileName=Pilot%20Statement-Master.PDF - FAA Response Letter (item 3, .PDF, 979 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485169&FileExtension=.PDF&FileName=FAA%20Response%20Letter-Master.PDF - NTSB Wreckage Examination Summary (item 4, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485170&FileExtension=.PDF&FileName=NTSB%20Wreckage%20Examination%20Summary-Master.PDF - Onsite Photo Array (item 5, .PDF, 302 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485171&FileExtension=.PDF&FileName=Onsite%20Photo%20Array-Master.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.