Aviation Accident Summaries

Aviation Accident Summary SEA95FA095

MILFORD, UT, USA

Aircraft #1

N2115S

CESSNA T210L

Analysis

The pilot had received a weather briefing which included an AIRMET referencing occasional moderate rime ice or mixed icing in clouds in precipitation between 9,000 and 20,000 feet. The aircraft, which was not equipped with anti-ice/deice equipment, departed Provo at approx 1544. At 1607, the pilot radioed that he was picking up ice. At 1647 he stated that he wanted to deviate due to weather. At 1657 and again at 1702 he radioed that he was picking up ice. The controller recommended a course reversal following the 1702 call and the pilot responded 'we're doing that.' The aircraft's radar track, combined with satellite imagery of cloud activity near the time of the accident, showed the aircraft penetrating the core of a convective buildup just prior to the accident. Freezing level was near 8,000 feet and the temperature/dew point spread between 8,000 and 13,000 feet was approx 1 degree C. The aircraft impacted the ground upright in a nose low, wings level attitude.

Factual Information

HISTORY OF FLIGHT On May 7, 1995, approximately 1710 hours mountain daylight time, a Cessna T210L, N2115S, registered to and being flown by a private, instrument-rated pilot, was destroyed during an inflight collision with terrain during an uncontrolled descent. The aircraft had encountered icing while in cruise followed by a loss of control in flight during an attempted climb. The accident site was 38 nautical miles west southwest of Milford, Utah, and a post-crash fire destroyed much of the aircraft. The pilot, his wife, and four children sustained fatal injuries. Instrument meteorological conditions existed in the vicinity of the accident site, and an instrument flight rules (IFR) flight plan was in effect. The aircraft had departed Provo, Utah, at 1546 en route to Visalia, California. The flight, which was personal, was to have been operated under 14CFR91. Approximately 1517, the pilot of N2115S contacted the Cedar City Automated Flight Service Station (AFSS) via telephone and requested a weather briefing for an IFR flight from Provo to Visalia. The Air Traffic Control Specialist requested a proposed "OFF" time from Provo and the pilot responded "as soon as you can get me in the system, we're ready to go." The specialist subsequently provided a weather briefing, including AIRMET Sierra "for possible mountain obscurement through most of the way" and AIRMET Zulu "for occasional moderate rime ice or mixed icing in the clouds in precipitation between niner thousand and two zero thousand" (refer to ATTACHMENTS WB-I and PS-I). The pilot then filed an IFR flight plan and the telephone conversation was terminated approximately 1524. An employee for the fixed base operator (FBO), who was present when the pilot and his family returned to the airport on the afternoon of May 7th, was interviewed and reported that the pilot arrived approximately fifteen minutes before the hour and called for a weather briefing. He described the pilot as "real rushed" and stated that he "hurried the kids out the door" telling them "We've got a long trip - let's get going." At 1544, the pilot of N2115S radioed Salt Lake City Approach Control and advised he was ready for departure (refer to ATTACHMENT RAA-I). The aircraft departed Provo shortly thereafter and was "recleared via Victor 21 to Delta then as filed." At 1558:11, the pilot of N2115S contacted Salt Lake Air Route Traffic Control Center (ARTCC) reporting "Cessna 2115S with you at ten point two climbing to one one thousand." At 1606:48, the pilot radioed, "is there any chance we can get eleven thousand instead of twelve (unintelligible) wrong direction we're picking up a little ice." The aircraft was then cleared to maintain 11,000 feet and the pilot report that the type of icing encountered was "a little bit of mixed." The aircraft was subsequently switched to a different center frequency at 1619:56 (refer to ATTACHMENT CT-I). At 1632:37, the aircraft was issued a climb to 12,000 feet which was acknowledged by the pilot, and at 1646:40 the pilot radioed that "we need to deviate a little bit uh we've got some weather right ahead of us we'd like to go to the left uh oh twenty degrees for a little bit," and this request was approved. At 1650:50, the controller contacted N2115S and stated "be advised a Douglas DC3 uh just overhead Cedar City's getting moderate mixed rime icing there at one three thousand, I'm not sure what you can encounter at uh one two thousand." Between 1654:38 and 1657:14, the controller made several attempts to contact N2115S without success. Then, at 1657:14, the pilot of 2115S radioed "center this is 15 Sierra we're picking up some ice can we at all go at all lower" and the controller responded "uh negative sir I do not have lower available uh you should be in the clear at one four thousand are you capable of one four thousand?" The pilot then accepted a climb to 14,000 feet and at 1700:44 was switched to Salt Lake ARTCC frequency 113.45 mHz (refer to ATTACHMENT CT-II). At 1702:07, the pilot radioed on the new frequency "center, this is one five Sierra, we're picking up lots of ice, we've got to do something." At 1702:11, the controller responded "November one five Sierra suggest you uh reverse course and proceed uh back to where you were, over" followed at 1702:23 by "Centurion two one one five Sierra suggest you reverse course immediately." At 1702:27, the pilot of N2115S responded "we're doing that sir" (refer to ATTACHMENT CT-III). This was the last radio trans- mission received from the aircraft. Radar data provided by the FAA ARTCC showed the aircraft tracking generally northwest and then beginning a left turn to reverse course approximately 1702:28. The last radar target with a mode "C" altitude report was at 1702:59 at an altitude of 12,600 feet. Two additional targets were received without altitude information and the last target placed the aircraft approximately one quarter mile south of the ground impact site (refer to ATTACHMENT RD-I and CHART I). The aircraft's altitude fluctuated up and down several hundred feet during the last several minutes of recorded radar data and then transitioned into a descent (refer to CHART "R"). PERSONNEL INFORMATION The only flight-time information available was the pilot's total flight time as of his most recent FAA medical of January 11, 1994. At that time the pilot reported a total of 750 hours flight time. AIRCRAFT INFORMATION The aircraft had been topped off with 62.7 gallons of 100 low lead aviation gasoline upon its arrival at Provo on May 5th. The fueler for the FBO reported that the aircraft had arrived from California and that there were "lots" of soft side suitcases taken off the plane. The aircraft was not equipped with wing/tail de-icing boots, propeller de-ice, nor windshield de-ice. No airframe/engine logs were located during the investigation. METEOROLOGICAL INFORMATION The National Weather Service (NWS) 1500 and 1800 surface analysis charts showed a low pressure area centered over southeastern Colorado with a trough line extending west into southern Utah. The NWS 700 millibar chart (approximately 10,000 feet above mean sea level [msl]) indicated generally northwesterly winds with temperatures from minus two to minus three degrees Celsius over western Utah (refer to attached Weather Factual Report). The Ely, Nevada, radiosonde taken near 1800 hours and released approximately 75 nautical miles northwest of the accident site revealed the freezing level near 8,000 feet msl with an approxi- mate one degree temperature/dew point spread from 8,000 feet upwards until passing 13,000 feet msl. Satellite imagery for the location of the accident site showed clouds and cumulonimbus activity in the vicinity at 1702 hours. AIRMET Sierra Update 3, which was valid until May 7, 2000 hours, reported "mountains occasionally obscured by clouds/precipi- tation. Conditions continuing beyond 2000 through May 8, 0200." Additionally, AIRMET Zulu Update 3, which was valid for icing and freezing level until May 7, 2000 hours, reported "occasional moderate rime/mixed icing in cloud between 9,000 feet and 20,000 feet. Conditions continuing beyond 2000 through May 8, 0200." The Beaver County Sheriff's Department interviewed witnesses who lived in the vicinity of the accident site and reported the weather conditions on the afternoon of May 7th. The Sheriff's report stated that the "witnesses gave verbal statements that the weather during the afternoon was raining to snowing with high winds" (from Beaver County Sheriff's Department report Id:# 31143.A02). WRECKAGE AND IMPACT INFORMATION The crash site was located 38 nautical miles west southwest of Milford, Utah. The latitude and longitude of the site was 38 degrees 20.08 minutes north and 113 degrees 48.10 minutes west, and the elevation was approximately 6,350 feet MSL (refer to CHART I). The terrain at the site was very gently sloped with occasional pinion/cedar trees. The aircraft was observed at the ground impact site in an upright attitude with the longitudinal axis oriented along a 346/166 degree magnetic bearing (nose north). A 13.5 foot high pinion tree was observed against the aircraft's left wing leading edge approximately mid span. This tree (T1, page 3, Supplement I) had sustained fire damage but showed no significant impact marks other than at its base. A second 24 foot high pinion tree (T2, page 3, Supplement I) was observed bearing 183 degrees from the center of ground impact site and 40 feet distant. This tree displayed no fire or impact damage (refer to photographs 1 through 5). The fuselage and cabin area had been consumed by fire, rendering all instrumentation unreadable (therefore, Supplement "B" for this report was not completed), and only the extremities of the aircraft (outboard wings and tail section) were intact. The engine was observed to be imbedded in the soil in an approximate 40 degree nose-down angle below the horizon with the propeller attached but the hub assembly shattered (refer to photograph 5). One of the fuel caps was found lying on the ground near the fuselage and the other fuel cap was found 90 feet north of the ground impact site. Vegetation to the north of the site was observed to have been exposed to brief but intense heat from a fire. The horizontal and vertical stabilizers remained attached to the empennage as well as their respective control surfaces. The tail had sustained fire damage and the leading edge of the vertical stabilizer displayed an aftward crushing indentation which matched the shape of the wing spar carry through member situated above the cockpit (refer to photographs 6 through 8). The aircraft's initial ground impact site and final resting place were coincident. Both wings sustained extensive aftward accordion like compressive damage (refer to photographs 9 through 12) and the engine case was observed to be cracked (refer to photograph 13). All three propeller blades were removed from the broken propeller hub assembly and each displayed light "S" bending (refer to photograph 14). Additionally, all three blades displayed light scuffing and chordwise scratching and abrasion (refer to photographs 15 through 17). The vacuum pump was examined and its coupler was noted to be intact. When opened, the carbon cylinder and blades displayed numerous breaks, however, there was no buildup of carbon particu- lates within the pump chamber. Additionally, the turbocharger was opened and the turbine blades displayed bending opposite to the direction of rotation. MEDICAL AND PATHOLOGICAL INFORMATION Post mortem examination of the pilot was conducted by Edward A. Leis, M.D., on May 8, 1995, at the offices of the Utah Medical Examiner, 48 North Medical Drive, Salt Lake City, Utah, 84113. Toxicological examination of samples from the pilot was conducted by the State of Utah, Department of Health (Office of the Medical Examiner). No toxicological samples were transmitted to the FAA's Civil Aeromedical Institute for evaluation. A screen of muscle tissue was negative for general (GC-ABN) drugs. Dr. Leis reported that no other tests were conducted due to the unsuitability of samples. ADDITIONAL INFORMATION On site examination was conducted on May 9, 1995, and the wreckage, which remained at the site, was verbally released to Mr. Robert Kern on the same day. Written wreckage release was executed on May 10, 1995 (refer to NTSB Form 6120.15).

Probable Cause and Findings

the pilot's continued flight into known adverse weather (icing conditions), and his delay in executing a course reversal to exit those conditions, which resulted in airframe ice accumulation and loss of control. A factor was the icing conditions.

 

Source: NTSB Aviation Accident Database

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