# NTSB CHI96FA052: Piper PA-23-250, N54791, Steuben, WI, December 12, 1995 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Field investigation · Final report - Date: December 11, 1995, 18:20 local (Dec 12, 1995, 00:20 UTC) - Place: Steuben, WI - Coordinates: 43.180042, -90.849502 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.1800&lon=-90.8495&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 3 serious, 1 minor - Status: Completed, report March 21, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 10064 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI96FA052 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/10064/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=10064 - Page: https://openairdocs.org/ntsb/CHI96FA052 ## Probable cause failure of the pilot to select alternate air. Darkness and snowy weather conditions were related factors. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, cruise - weather condition - snow (contributing factor) - Loss of engine power(total) - nonmechanical, cruise - all engines - induction air control,alternate air/door - miscellaneous equipment - not selected, pilot in command (cause) - Forced landing, emergency descent/landing - In flight collision with object, emergency descent/landing - light condition - dark night (contributing factor) - object - tree(s) - In flight collision with terrain/water, emergency descent/landing ## Analysis ACCORDING TO A REAR SEAT PASSENGER, THE AIRPLANE WAS FLYING THROUGH HEAVY SNOW, WHEN BOTH ENGINES LOST POWER. THE LOSS OF POWER OCCURRED AS THE AIRPLANE WAS FLYING IN INSTRUMENT CONDITIONS AT NIGHT. SUBSEQUENTLY, THE AIRPLANE DESCENDED AND WAS DESTROYED, WHEN IT COLLIDED WITH TREES. DURING AN EXAMINATION OF THE AIRPLANE ON DECEMBER 13, 1995, ICE WAS FOUND IN THE AIR INDUCTION SYSTEM OF BOTH ENGINES. NO OTHER AIRPLANE OR ENGINE MALFUNCTION WAS FOUND DURING THE EXAMINATION. THE PILOT'S OPERATING HANDBOOK STATED THAT ALTERNATE AIR SHOULD BE PLACED IN THE FULL 'ON' POSITION PRIOR TO ENTERING KNOWN OR EXPECTED ICING CONDITIONS. ## Factual narrative On December 11, 1995, at 1820 central standard time (cst), a Piper PA-23-250, N54791 was destroyed when it collided with trees and terrain. The pilot reported a loss of power on both engines to Chicago Center, prior to impact. Instrument meteorological conditions prevailed at the time of the accident. The personal 14 CFR Part 91 flight was operating on a IFR flight plan. The pilot and two passengers sustained serious injuries. One passenger received minor injuries. The flight departed from Wausau, Wisconsin en route to Tulsa, Oklahoma at 1740 cst. The 400 foot wreckage path followed a magnetic heading of 160 degrees. All airplane components were found along the wreckage path. Due to the weather forecast for six inches of snow the evening of December 12, 1995, the airplane wreckage and cockpit were documented, and then moved from the accident location to a unheated airplane hanger. Photographs 1-4 show the wreckage as documented on December 12, 1995. During the airplane inspection on December 13, 1995, ice was found in the air induction system of both engines. No other airplane or engine malfunction was found on December 13, 1995. Photographs 5-8 show the air box, air filter box and air filter as removed from the right engine on December 13, 1995. Numerous pieces of ice were found in the right air box, beyond the air filter. Photographs 9 and ten show the fuel control unit and air filter for the left engine as photographed on December 13, 1995. All four impact tubes in the left fuel control unit were completely covered with ice. With the impact tubes blocked by ice, the diaphragm in the fuel control unit would not supply any fuel to the left engine's cylinders. Both alternate air controls were found in the off position as documented on December 12, 1995, at the accident site. Both left and right air valves were found in the filtered air position on December 13, 1995. Both alternate air cockpit controls could be moved on December 13, 1995. In a personal interview with the investigator in charge (IIC) a rear seat passenger said the airplane was flying through heavy snow, prior to the loss of power on both engines. The passenger also said that it was a very short time period between the loss of power on the left engine and the loss of power on the right engine. The pilot's operating handbook was reviewed by the IIC and states that "On the control pedestal are two manual alternate air controls which may be used by the pilot to select alternate air if the automatic feature should fail. These should be placed in the FULL "ON" position prior to entering known or expected icing conditions." ## Aircraft - Registration: [N54791](https://openairdocs.org/deregistered/N54791-1997-01-30), registration cancelled 1997-01-30, S/N 277554092 (OpenAirDocs) - Reported make and model: PIPER PA-23-250 - Registry model: [Piper PA-23-250](https://openairdocs.org/model/piper-pa-23-250) (registry code 7102308) (OpenAirDocs) - Category: Airplane - Serial number: 27-7554092 - Airframe hours: 6639 - Engines: LYCOMING IO-540-C4B5 250 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Operator: Robert G. Timm - Registered owner: Spirt Of St. Louis Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 9, 1995, 86 hours before - Departed: AUW, WAUSAU, WI - Destination: TUL, TULSA, OK - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 10,000 total, 250 in this make and model ## Weather - Conditions: Instrument (IMC), Night/dark - Wind: 60° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: 10,000 ft overcast - Temperature: 3 °F, dew point -0 °F - Altimeter: 30.00 inHg - Observed at: DBQ, 55 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 19951211040329A](https://openairdocs.org/incident/19951211040329A), Dec 11, 1995: Piper PA23250, Boscobel, WI, Destroyed. Flying in heavy snow. Lost power IFR at night. Hit trees landing. Iced induction system. Failed use alternate air. (-23) aircraft departed the central… ## Docket (12 files) The files NTSB released with the investigation on June 28, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=10064. 2.2 MB in all. - Supplement a (item 1, PDF, 2 pages, 207 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15312786&FileExtension=pdf&FileName=Supplement%20A-Master-Rel.pdf - Supplement b (item 2, PDF, 4 pages, 289 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15311955&FileExtension=pdf&FileName=Supplement%20B-Master-Rel.pdf - Supplement s (item 3, PDF, 1 page, 46 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15311958&FileExtension=pdf&FileName=Supplement%20S-Master-Rel.pdf - Pilot-operator aircraft accident report NTSB form 61201-2 (item 4, PDF, 8 pages, 524 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15312205&FileExtension=pdf&FileName=Pilot-Operator%20Aircraft%20Accident%20Report%20NTSB%20Form%2061201-2-Master-Rel.pdf - Photo 1 main wreckage (item 5, PDF, 1 page, 176 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=1437501&FileExtension=pdf&FileName=Photo%201%20%20Main%20Wreckage-Master.pdf - Photo 2 cabin area (item 6, PDF, 1 page, 187 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=1437503&FileExtension=pdf&FileName=Photo%202%20%20Cabin%20Area-Master.pdf - Photo 3 left propeller (item 7, PDF, 1 page, 141 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=1437505&FileExtension=pdf&FileName=Photo%203%20%20Left%20Propeller-Master.pdf - Photo 4 right propeller (item 8, PDF, 1 page, 123 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=1437507&FileExtension=pdf&FileName=Photo%204%20%20Right%20Propeller-Master.pdf - Photo 5 right engine fuel control air box (item 9, PDF, 1 page, 117 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=1437509&FileExtension=pdf&FileName=Photo%205%20%20Right%20Engine%20Fuel%20Control%20Air%20Box-Master.pdf - Photo 6 right engine air filter (item 10, PDF, 1 page, 127 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=1437511&FileExtension=pdf&FileName=Photo%206%20%20Right%20Engine%20Air%20Filter-Master.pdf - Photo 7 left engine air filter and fuel control (item 11, PDF, 1 page, 134 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=1437513&FileExtension=pdf&FileName=Photo%207%20%20Left%20Engine%20Air%20Filter%20and%20Fuel%20Control-Master.pdf - Photo 8 left engine fuel control (item 12, PDF, 1 page, 137 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=1437515&FileExtension=pdf&FileName=Photo%208%20%20Left%20Engine%20Fuel%20Control-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.