Casper, WY, USA
N357
CESSNA T337
The pilot received two predeparture weather briefings, both of which reported that snow showers were expected over most of the state. During the second briefing, the pilot was advised that adverse weather conditions, including mountain obscuration, moderate icing, moderate turbulence, and low-level wind shear, existed throughout the planned route of flight. The pilot still decided to depart. As the airplane neared its destination, the approach controller issued the pilot vectors to the final instrument landing system approach course. The approach controller subsequently saw that the airplane was at 6,900 feet mean sea level (msl), which was 300 feet below the minimum vectoring altitude for the approach (7,200 feet msl). The approach controller issued the pilot a low altitude alert, and the pilot climbed the airplane back to the minimum vectoring altitude of 7,200 feet msl. About 1 minute after the approach controller transferred control of the flight over to the tower air traffic controller, the controller saw that the airplane was about 1/4 mile right of the inbound approach course. The controller then issued the pilot missed approach instructions, advising him to fly the runway heading and to climb and maintain 8,000 feet msl. The tower controller then transferred the pilot back to the approach controller, who advised the pilot that the runway visual range had decreased below that required for the approach. The pilot then elected to be vectored back to the final approach course to hold on the localizer until the weather improved. While he was issuing the pilot vectors to the localizer, the approach controller observed the airplane flying an inappropriate heading. After he advised the pilot of the irregularity, the approach controller issued a revised heading toward the localizer. The approach controller observed the airplane begin the right turn toward the assigned heading, and shortly thereafter, observed that the airplane was 1,200 feet below its assigned altitude. The approach controller issued the pilot another low altitude alert. There were no further radio communications with the pilot. The airplane impacted terrain about 8 nautical miles northeast of the airport, slightly left of the missed approach course, in a left-wing-low, steep nose-down attitude. About 2 minutes before the accident, the destination airport reported 1/2-mile visibility in moderate snow and freezing fog, with scattered clouds at 800 feet above ground level (agl) and an overcast cloud layer at 1,300 feet agl. Postaccident review of the weather conditions in the area at the time of the accident indicated that the pilot was operating in instrument meteorological conditions and that conditions were favorable for structural icing at a moderate to severe level. Postaccident examination revealed no evidence of preaccident mechanical malfunctions or failures that would have precluded normal operation. Based on the weather conditions that the pilot encountered while maneuvering near the destination airport, it is likely that the pilot failed to maintain adequate airspeed due to structural icing, which resulted in a loss of airplane control and subsequent impact with terrain.
HISTORY OF FLIGHT On November 18, 2011, about 1350 mountain standard time, N357, a Cessna 337G was substantially damaged after impacting terrain following a missed approach procedure at the Casper/Natrona County International Airport (CPR), Casper, Wyoming. The private pilot, the sole occupant of the airplane, was fatally injured. Instrument meteorological conditions prevailed for the personal cross-country flight, which was conducted in accordance with Title 14 Code of Federal Regulations (CFR) Part 91, and an instrument flight rules (IFR) flight plan was filed and activated at the time of the accident. The flight departed Rawlins Municipal/Harvey Field Airport (RWL), Rawlins, Wyoming, about 1315, with CPR as its destination. According to voice and radar data provided by the Federal Aviation Administration (FAA), while tracking the localizer inbound on the instrument landing system (ILS) to runway 03, the pilot was observed by the local tower controller to be about one-quarter mile right of track. At 1340:00, the controller informed the pilot of this condition, and requested that the pilot verify that he was aligned on the ILS for runway 03. The pilot responded, “Yeah. We’re having a little rodeo up here.” At 1340:11, the tower controller instructed the pilot to fly runway heading (030 degrees) and climb and maintain 8,000 feet for radar vectors around for another approach. At 1340:15, the pilot checked in with the approach controller, and informed him that he was on the missed approach. At 1340:28, the approach controller instructed the pilot to climb to and maintain 8,600 feet; the pilot confirmed the transmission. At 1341:47, the approach controller ask the pilot for the tower assigned heading, to which the pilot replied, “…uh, give me, uh, give me the heading again please.” The controller responded, "Skymaster three five seven, fly heading zero three zero. Turn left heading zero three zero." The pilot correctly read back the controller’s instructions. At 1343:27, the approach controller advised the pilot that the runway’s runway visual range (RVR) was currently two thousand, below the minimums for the ILS approach to runway 03, but that he would give the pilot a choice of either holding at Muddy Mountain, or he could vector him back around to hold on the localizer; the pilot chose to be vectored for the approach. At 1343:57, the controller instructed the pilot to turn left to a heading of 310 degrees for vectors to the runway 03 ILS approach; the pilot confirmed the heading as 310 degrees. At 1345:40, the controller instructed the pilot to turn left to a heading of 270 degrees, and again the pilot confirmed the heading. At 1346:58, the controller instructed the pilot to turn left to a heading of 220 degrees, and advised the pilot that the RVR was steadily increasing. At 1347:26, the pilot replied, “Okay. Could you say again. We’re, uh, we had a lot of squealing on the radio there.” The controller again instructed the pilot to turn left to a heading of 220 degrees, that the RVR for runway 03 was 2,800, that it looked to be increasing, and that he would advise him as he got closer to his base leg. At 1348:05, the approach controller advised the pilot of N357 that he had him tracking about a 130 degree heading, and to fly a downwind heading of 250 degrees for the ILS approach to runway 03. At 1348:17, the pilot replied, “Two five zero. Three five seven.” At 1348:35, the controller radioed to the pilot, “Skymaster three five seven. Low altitude alert. Check your altitude immediately. Minimum vectoring altitude (MVA) in your area is seven thousand five hundred. Climb and maintain eight thousand six hundred. Are you having trouble maintaining altitude?” There were no further transmissions from the pilot. About 1 minute later, radar contact was lost with the airplane and attempts by ATC to make contact by radio were unsuccessful. The airplane was located about 8 miles northeast of CPR in a snow-covered area of gently rolling terrain with sparse vegetation. A survey of the wreckage, which had come to rest upright in a tightly confined area, revealed that all major components of the airplane were accounted for at the accident site. The airplane had been consumed by a postcrash fire. A FAA aviation safety inspector assigned to the FAA’s Flight Standards District Office in Casper, reported that he was one of the first responders to the accident site. The inspector stated that due to the thermal distress that the airplane had sustained, there was no evidence of any ice accumulation on any part of the airplane. Subsequent to the onsite documentation of the wreckage being completed, the airplane was recovered to a secured storage facility for further examination. PERSONNEL INFORMATION The pilot/co-owner, age 61, held a private pilot certificate with airplane single-engine land, multiengine land, and instrument airplane ratings. The pilot’s most recent logbook entry, dated February 18, 2011, revealed a total time of 4,582 hours, 4,487.8 hours of which was pilot in command. The pilot logged 702 hours of airplane multiengine time, 3,843 hours of airplane single-engine time, and 687.3 hours in the make and model of the accident airplane. Additionally, the pilot recorded 644.7 hours of actual instrument time and 648.9 hours of night time. A further review of the pilot’s logbook revealed that his most recent instrument approaches, 10, had been completed in a simulator on February 15, 2011, while attending training at the facilities of Recurrent Training Center, Inc., Savoy, Illinois. This training was documented with a signed off sticker placed in the back of the pilot’s logbook. Personnel at Recurrent Training Center refused to provide training records consistent with the training provided to the pilot on February 15, 2011. Additionally, and subsequent to the training being satisfactorily completed, on February 15, 2011, the pilot logged a 4.9 hour cross-country IFR flight from the University of Illinois-Willard Airport (CMI), Champaign/Urbana, Illinois, to the North Platte Regional Airport (LBF), North Platte, Nebraska, during which the pilot logged 1.0 hours of actual instrument flight time; no instrument approaches were noted during this flight. From the pilot's last logbook entry on February 18, 2011, up to the date of the accident, which occurred almost 9 months to the day of his last logbook entry, the pilot's logbook contained no other entries of instrument flight time or of instrument approaches being completed. The co-owner of the airplane provided additional documentation, which indicated that from March through the end of October, 2011, the accident pilot had accumulated a total of 40.3 hours in the accident airplane. However, there was no breakdown of flight time in instrument meteorological or visual meteorological conditions. The data provided indicated that the pilot flew the accident airplane about 12 hours in the last 90 days, 1.2 hours in the last 60 days, and no flight time in the 30 days preceding the date of the accident. FAA records indicated that the pilot's most recent third-class airman medical certificate was issued on May 6, 2011, with the limitation that the pilot "must wear corrective lenses." AIRCRAFT INFORMATION The pressurized, in-line thrust airplane was manufactured in 1976. It was being operated with a standard airworthiness certificate in the normal category. The airplane was equipped with two Continental TSIO-360-series engines, each rated at 225 horsepower, and McCauley two-bladed, constant-speed propellers. The airplane was on an annual inspection maintenance program, which was last performed on April 5, 2011, at a total airframe time of 3,187.1 hours. Aircraft maintenance records revealed per a logbook entry dated September 30, 2011, that the rear engine, serial number 1000310, and the front engine, serial number 824819-R, had accumulated a total of 473.3 hours since their last overhaul. The airplane was equipped with navigational and flight instruments suitable for flight in instrument meteorological conditions (IMC). On February 12, 2012, an ASPEN Electronic Flight Display (EFD) 1000PRO was installed. The EFD featured an autopilot and flight director, integral altitude alerter, slaved directional gyro with heading bug, a base map with flight plan legs and waypoints, curved flight paths and nearby navaids. In addition, the unit featured GPS flight plan map views, 360 degree ARC, display of real-time winds aloft, outside air temperature, true and ground speed, and an integral air data computer and attitude heading reference system (AHRS). The airplane was also equipped with the Cessna “Known Icing Conditions” deice system kit, which was comprised of an electric deicing pilot’s windshield panel, wing and empennage deice boots, heated pitot head and static ports, and propeller deice boots. A review of maintenance records revealed that on February 10, 2011, the airplane was inspected in accordance with Federal Aviation Regulation, Title 14, Part 91.411, Altimeter system and altitude reporting equipment tests and inspections, which states, “No person may operate an airplane in controlled airspace under IFR conditions, unless within the preceding 24 calendar months, each static pressure system, each altimeter instrument, and each automatic pressure altitude reporting system has been tested and inspected and found to comply with appendix E, of part 43 of this chapter.” METEOROLOGICAL INFORMATION The pilot obtained an outlook weather briefing and filed an IFR flight plan with the Prescott, Arizona FAA Contract Automated Flight Service Station (AFSS) at 1834 MST on November 17, 2011. The pilot subsequently obtained an abbreviated weather briefing at about 1200 MST on November 18, 2011. In both briefings, the AFSS briefer indicated that snow showers were expected over the majority of Wyoming during the period. In the latest briefing at 1200 MST, the briefer provided the adverse weather conditions expected, and indicated that AIRMETs for IFR and mountain obscuration conditions, moderate icing, moderate turbulence, and low-level wind shear were current over the route of flight. The freezing level was identified at the surface, with multiple layers of cloud identified and implied existing icing conditions. At 1335, about 5 minutes prior to the time of the accident, a CPR special weather observation indicated wind 360 degrees at 8 knots, visibility 1 ¾ miles, light snow and mist, scattered clouds at 800 feet, scattered clouds at 1,200 feet, overcast clouds at 2,500 feet, temperature -1 degree Celsius (C), dew point -3 degrees C, and an altimeter setting of 29.56 inches of mercury (Hg). Remarks: automated observation system, hourly precipitation 0.01 inch. At 1348, about 8 minutes after the time of the accident, a CPR special weather observation revealed wind 010 degrees at 8 knots, visibility ½ mile in moderate snow and freezing fog, few clouds at 800 feet, overcast clouds at 1,300 feet, temperature -2 degrees C, dew point -3 degrees C, and an altimeter setting of 29.55 inches of mercury (Hg). Remarks: automated observation system, hourly precipitation 0.01 inch. Subsequent observations indicated that snow was reported at CPR earlier in the morning between 0740 and 0804 on November 18, 2011, and began again prior to the accident at 1247, with conditions rapidly deteriorating to IFR conditions with wet snow, mist, and freezing fog with the snow ending at 0036 on November 19, 2011. The Terminal Aerodrome Forecast (TAF) for Casper (CPR) was issued at 1031 MST on November 18, 2011 prior to N357’s departure for preflight weather planning. The forecast for KCPR from 1100 MST expected wind from 080° at 7 knots, visibility better than 6 miles with showers in the vicinity, scattered clouds at 4,000 feet agl, ceiling broken at 6,000 feet, with the threat of windshear at 1,000 feet with a wind from 230° at 35 knots. From 1400 MST, wind from 300 at 9 knots, visibility better than 6 miles, with showers in the vicinity, scattered clouds at 5,000 feet, ceiling broken at 8,000 feet. The area forecast for Wyoming east of the continental divide was for a broken layer of clouds at 8,000 feet with tops to 20,000 feet with visibility 5 miles in scattered light snow showers, becoming from 1500 to 1700 MST overcast at 7,000 feet with visibility 3 miles in light snow. The outlook from 1700 through 2300 MST was for MVFR conditions due to low ceilings and visibilities in snow. The National Weather Service (NWS) had AIRMET Sierra update number 3 for IFR conditions for ceilings below 1,000 feet agl and/or visibility less than 3 miles in precipitation, mountain obscuration conditions in clouds and precipitation. AIRMET Tango update number 5 for occasional moderate turbulence below 16,000 feet, and for low-level wind shear (LLWS). AIRMET Zulu update 2 was also current over the region for moderate icing conditions below 20,000 feet. The NWS Weather Depiction Chart for 1200 MST on November 18, 2011, depicted an area of instrument flight rule (IFR) conditions over western and central Wyoming, with visibility of less than 2 miles in light to moderate snow and low ceilings. The station model for Casper at 1200 MST depicted VFR conditions prevailing with overcast clouds at 5,000 feet, with the area of MVFR and IFR conditions to the west. A Senior National Transportation Safety Board (NTSB) meteorologist supplied the NTSB investigator-in-charge (IIC) with Geostationary Operational Environmental Satellite number 11 (GEOS-11) data. The GEOS-11 visible image at 1345 MST indicated several layers of clouds over Wyoming with an overcast layer of nimbostratus type clouds consistent with snow showers over the accident site. The NTSB meteorologist also provided the NTSB IIC with National Weather Service Current Icing Potential (CIP) products, which were obtained through the National Center for Atmospheric Research (NCAR) surrounding the period of the accident. One product, a cross section for the route of flight between Denver and Casper for 1300 MST indicated a deep layer of potential moderate icing conditions between 6,000 to 19,000 feet over the Casper area, with a 60 to 80 percent probability of occurrence at the accident airplane’s cruising level and approach into the Casper area. The visible moisture and relative humidity was between 80 to 100 percent over Casper, with temperatures below freezing through the entire depth of the atmosphere over the area. Further, the icing probability for the cruising level of 13,000 feet for 1300 MST depicted a greater than 50 probability of icing conditions at 13,000 feet with areas of 70 percent and more in the vicinity of Casper. The icing severity chart for 13,000 feet depicted a large area of moderate icing conditions over central Wyoming with scattered areas of heavy or severe icing conditions for 1300 MST. Another chart, which was the best category of icing conditions, continued to depict moderate to heavy icing over the region at the time of the accident. For a detailed discussion of the weather information, see the Meteorology Factual Report in the public docket for this accident. AIDS TO NAVIGATION The CPR ILS Runway 03 Approach utilizes a glide slope and a final approach course of 032 degrees magnetic, with an initial approach fix (CHOMP) located 36 DME on the Muddy Mountain (DDY) VOR 204 degree radial. The charted minimum altitude for holding at DDY is 7,500 feet. The DDY VOR was utilized as the holding fix that was part of the missed approach procedure, and was located about 14 nautical miles northeast of CPR. The missed approach procedure specified a climb to 7,500 feet, followed by a left turn direct to the DDY VOR and hold. The published holding procedure indicates standard right hand turns northeast of the DDY on the 025 radial. The published landing minimums for the approach required a runway visual range (RVR) of 2,400 feet, a decision height of 5,524 feet mean sea level (msl), or 200 feet above ground level. The CPR airport elevation is listed as 5,350 feet msl. AIRPORT INFORMATION CPR was serviced by an operating air traffic control tower, which incorporated approach and departure serv
The pilot's failure to maintain airspeed and airplane control while maneuvering in low visibility and icing conditions.
Source: NTSB Aviation Accident Database
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