Reno, NV, USA
N948CC
Beech E90
During an instrument approach, upon descending to the prescribed minimum descent altitude, about 1/2 mile from the missed approach point, the pilot failed to maintain flying airspeed. The airplane stalled, rolled left, and in an uncontrolled descent collided with a commercial building 0.96 nm from the runway's displaced threshold. The accident occurred during the return portion of a round trip flight, while on final approach to the pilot's alternate airport due to a weather-induced diversion. Moderate intensity snow showers and freezing fog existed. During the initial approach, the reported visibility was 1 1/2 miles. About the time the pilot passed the final approach fix, the visibility decreased to 1/2 mile, but the pilot was not informed of the decrease below his 1-mile minimum requirement. The pilot had maintained the recommended 140-knot approach speed in the icing conditions until about 3 1/2 miles from the runway. Thereafter, the airplane's speed gradually decreased until reaching about 75 knots. After the airplane started vibrating, the pilot increased engine power, but his action was not timely enough to avert stalling. Company mechanics maintained the airplane. On previous occasions overheat conditions had occurred wherein the environmental ducting melted and heat was conducted to the adjacent pneumatic tube that provides deice air to the empennage boots. During the accident investigation, the deice tube was found completely melted closed, thus rendering all of the empennage deice boots dysfunctional.
HISTORY OF FLIGHT On March 13, 2002, about 1940 Pacific standard time (PST), a Beech E90, N948CC, descended into an unoccupied commercial building during an in-flight loss of control, about 1 mile south-southeast of the Reno/Tahoe International Airport, Reno, Nevada. Pilot Services Corporation, d.b.a. Regent Air Service, Inc., Truckee, California, operated the airplane. The accident occurred during a nighttime instrument approach in instrument meteorological conditions. The airline transport certificated pilot and four passengers sustained minor injuries, and a fifth passenger sustained a serious injury. The airplane was destroyed. The flight was operated under the provisions of 14 CFR Part 135 as an on-demand air taxi flight, which departed from Durango, Colorado, about 1625 mountain standard time (1525 PST). Earlier in the day, about 0518 PST, the pilot and passengers had departed from the Truckee-Tahoe Airport, Truckee, California, for the planned round trip flight to Durango. The pilot landed in Durango about 0850 mountain standard time (0750 PST). The pilot reported to National Transportation Safety Board investigators that thereafter, he ate lunch and retired at the prearranged crew-rest hotel. The pilot further indicated that the airplane was refueled, and he did not observe any discrepancies with the airplane during his preflight inspection for the planned nonstop return flight. According to the pilot, the flight was uneventful until he attempted to land at the Truckee-Tahoe Airport, his home base. At 1905 PST, the pilot received a clearance to perform an instrument approach to the Truckee-Tahoe Airport. Prior to commencement of the approach, the pilot activated the airplane's anti-ice systems, and they remained on throughout the remainder of the flight. The pilot activated the pneumatic wing deice boots prior to reaching the final approach fix. The pilot indicated that he initiated the approach but could not land because of his inadequate visibility; it was snowing. The pilot executed a missed approach at 1919. Thereafter, he requested and received a clearance with radar vectors to proceed to the Reno/Tahoe International Airport. The pilot further reported that snow showers also existed at Reno, and on only one occasion did he activate the deice boots during the approach. That occurred while on a vector to intercept the localizer, distance measuring equipment (DME), back course instrument approach to runway 34L. The pilot stated that he never observed an appreciable amount of ice on the leading edge of the wing, but he felt that there was enough to activate the boots. The pilot stated that when he activated the boots, "a little (ice) came off." He could see ice on the side of the wing's stall strip. There was some thin ice on the boot, but it did not extend beyond the boot. At 1925:27, the pilot was cleared to perform the instrument approach. During the Safety Board investigator's subsequent interview with the pilot, he indicated that it was his belief that, upon reaching the final approach fix, the airport's reported weather was at or above his landing minimums. At 1936:44, the pilot made his last recorded radio transmission during which he acknowledged being cleared to land. The pilot stated that everything on the approach was normal outside of the 2-mile DME fix. However, control of the airplane became difficult inside the 2-mile DME fix. The pilot further reported to Safety Board investigators that the airplane's approach was initially stabilized upon reaching the minimum descent altitude (MDA). At the MDA, he increased engine torque (power) to 800 foot-pounds per engine in order to maintain altitude. According to the pilot, a torque value between 700 and 900 foot-pounds is normal. The pilot indicated that some ice was visible on the wing's leading edge stall strip, but opined it was "way less than 1/4-inch" in depth. He stated that the ice did not extend beyond the aft portion of the wing's deicing boot. According to the pilot, during the final seconds of flight, the controls started vibrating and he felt a yawing moment. The pilot said that he instantly looked at the indicated airspeed, which was between 111 and 115 knots. Thereafter, the airplane started to shake. Previously, the airplane had been flying at 140 knots, the recommended approach speed for icing conditions. The pilot said that he applied full engine power; however, the airplane still shook and yawed. He recalled that the rudder pedals appeared to move freely. Although the vibration varied in intensity, once it started it never stopped. The pilot further reported that he pitched forward on the yoke, and he did not believe the airplane was stalling because the indicated airspeed was still near the "blue line." The pilot reported that he felt the airplane sink. While the airplane was sinking he noticed that the stall warning light was illuminated, and he attempted to stop the airplane's descent. He did not "yank back or push forward" on the yoke; he just maintained a level attitude. The pilot looked outside and saw buildings "coming up." The engine power was full, but the airplane was not climbing. The pilot reported thinking that he was going to hit the building and that he had to reduce the impact. Therefore, he pulled the yoke full back. The left wing stalled, and the airplane banked left. The pilot stated that there might have been ice on the tail because the tail "felt really weird." He said "something made the airplane go down when it shouldn't have." The airplane's last recorded radar position was at 1939:53. At this time, the airplane had descended to about 4,500 feet, as indicated by its Mode C altitude reporting transponder. The accident site's elevation is approximately 4,470 feet msl. PERSONNEL INFORMATION Certification and Experience. The pilot held an airline transport pilot certificate with an airplane multiengine land rating. He had commercial privileges in single engine land and sea airplanes. The pilot also possessed a certified flight instructor certificate with airplane single engine, multiengine, and instrument airplane privileges. He possessed advanced ground school instructor and aircraft dispatcher certificates. The pilot's last first-class aviation medical certificate was issued without limitations on May 14, 2001. The pilot's total flight time was 1,610 hours, of which 608 hours were flown in the model of the accident airplane. During the 30- and 90-day periods preceding the accident, the pilot had flown the accident model of airplane as pilot-in-command for 40 and 105 hours, respectively, of which 8 and 22 hours were in actual instrument meteorological conditions. Regent Air, Inc., hired the pilot in August 2000. In July 2001, he began flying the Beech E90 as pilot-in-command. The pilot's last FAR Part 135 competency, instrument proficiency, and line checks were performed by a Federal Aviation Administration (FAA) inspector in February 2002. All of the checks were completed satisfactorily. AIRCRAFT INFORMATION The Beech Aircraft Company began manufacturing the model E90 series of airplanes in 1972, with serial number LW-1. The accident airplane, serial number LW-236, was manufactured in 1977. Beech discontinued production of this model of airplane in 1981, with serial number LW-347. According to the Raytheon Aircraft Company participant, the interior configurations of these airplanes varied. As of April 2, 2002, FAA registration records indicated that 247 E90s were registered. Flight Manual and Check List Information. The FAA approved Airplane Flight Manual (AFM) contained the following statements regarding flight in icing conditions: "CAUTION Stalling airspeeds should be expected to increase when ice has accumulated on the airplane due to the distortion of the wing airfoil. For the same reason, stall warning devices are not accurate and should not be relied upon. Keep a comfortable margin of airspeed above the normal stall airspeed with ice on the airplane. Maintain a minimum of 140 knots during sustained icing conditions to prevent ice accumulation on unprotected surfaces of the wing...." A 6-inch by 12-inch spiral binder entitled "Beechcraft King Air E90 PILOT'S CHECK LIST" was recovered from the accident airplane. The binder's cover was imprinted with the name "Raytheon Aircraft Company," and all of the pages within were printed with "P/N 90-590012-7," and were dated "5/8/72." In part, the checklist identified actions the pilot should take in preparation for departure. Checking the functionality of the deice boots on the tail after the engines are started was not mentioned in the checklist. Airplane Certification, Equipment, and Instrument Markings. The pressurized, turboprop airplane was certificated by the FAA for flight into known icing conditions. The airplane was equipped with deice boots on its wings, and on the vertical and horizontal stabilizers. Unlike the wing mounted boots, from the cockpit the pilot cannot see all of the boots on the tail. The airplane is not equipped with an annunciator light or indicator gauge that shows the functionality of the tail-mounted boots. The airplane had been modified by installation of a Raisbeck Engineering conversion, and its AFM had been amended. The airplane's maximum gross weight was increased to 10,500 from its previous 10,100 pounds. According to Raisbeck personnel, the modification did not change the airplane's stall speed. Regarding the airspeed indicator, a blue radial line is present on the airspeed indicator. The line represents the best rate-of-climb airspeed (Vyse) with one engine inoperative. The placarded airspeed is 111 knots. Maintenance and Inspections. The pilot reported that, to the best of his knowledge, during the accident flight none of the installed equipment became dysfunctional. Moreover, no maintenance items had been deferred pursuant to a minimum equipment list. The pilot personally performed the pretakeoff, walk-around inspection of the airplane. The accident airplane had been on Regent Air's Part 135 certificate since July 1994. Regent Air's personnel reportedly maintained the accident airplane pursuant to the manufacturer's (Raytheon) recommended maintenance program. Maintenance inspections were reportedly accomplished in accordance with Raytheon Aircraft's Beech King Air 90 Maintenance Manual. This inspection program utilizes "Phase Inspections" and is accomplished at 200-hour intervals, identified as Phase 1 through 4. The complete program is scheduled to be accomplished at least one time every 24 calendar months. Each Phase Inspection is accomplished using a checklist. The Safety Board's Maintenance Group Chairman reviewed the checklists to identify the frequency of inspections to the environmental and pneumatic systems. The review noted that all four Phase Inspections checked the heating system. In part, the inspection included actions to check all ducts for damage and deterioration and to check the bleed ducts for damage. During all four inspections, the surface deice system was to be checked for proper operation and cycling, and the environmental system was to be checked for proper operation. The last Phase Inspection accomplished on the airplane prior to the accident was a Phase 4 Inspection. It was accomplished on February 28, 2002. At that time, the airplane's total time was 8,748.7 hours. At the time of the accident, the airplane's total time was 8,772.75 hours. A review of Regent Air's maintenance records revealed that between 1999 and 2001, the environmental air and pneumatic deice system had undergone maintenance. In part, in January 1999, tubing was replaced. In December 2000, new boots were installed. In 2001, holes in the vertical stabilizer were repaired, the cabin temperature controller was replaced, and static air pneumatic tubing located near the aft lavatory, which was found melted, was repaired. In September 2001, a Regent Air mechanic reported that he found melted EVA tubing near the aft pressure bulkhead. The mechanic determined that a leak was coming from a gasket at the rear of the cargo compartment, which supplies heat to the cabin (referring to the Station 277 heat vent). To stop the leak, the mechanic removed the vent cover and wrapped some aluminum tape around the gasket to seal the leak, and then he replaced the vent cover. The mechanic reported that it was not a normal practice to check the environmental tubing itself, which was wrapped inside of insulation material. Therefore, he did not check the environmental tubing during installation of the aluminum tape. He also stated that he only removed the aft floor panel to gain access to the vent. He did not remove the panel immediately forward of that location. (See the Safety Board's Maintenance Records Group Chairman's report for additional details.) METEOROLOGICAL INFORMATION Ground Personnel and Facility Reports. Nineteen minutes prior to the accident, at 1921, Reno fire department personnel had responded to a medical call about 3/4 mile southwest from where the accident would occur. The personnel noted that it was snowing lightly. However, by 1931, it was snowing heavily, the wind speed had increased, and the conditions appeared like a "squall blowing into the area with whiteout conditions." At 1930, Reno's automatic terminal information service (ATIS) was broadcasting "information Oscar." In pertinent part, the ATIS indicated that Reno's wind was from 290 degrees at 15 knots, and the visibility was 1 1/4 miles in light snow and mist. At 1932:30, the Reno south radar controller broadcast "Reno ATIS Oscar current." The controller advised the pilot, at 1933:16, that "...the last arrival seven twenty seven got the runway in sight mile and a half (unintelligible) south." The pilot was not provided with updated visibility information during the remainder of his approach. At 1939, the Reno/Tahoe International Airport's surface wind was from 300 degrees at 10 knots, and the visibility was 1/2 mile. There was moderate snow and freezing fog. A broken ceiling existed at 700 feet above ground level (agl), and an overcast sky condition existed at 2,500 feet agl. The temperature and dew points were, respectively, minus 2 and minus 3 degrees Celsius. The altimeter setting was 30.04 inches of mercury. After the accident, at 1956, Reno's visibility was also 1/2 mile in moderate snow and freezing fog. The vertical visibility was reported at 300 feet. Pilot Observations. According to the pilot, the first and only time he activated the deice boots going into Reno was on a radar vector to intersect the back course. This occurred less than 5 minutes before intercepting the back course. He activated the boots to get rid of the "residual" ice. Ice did deploy from the airplane. The pilot stated that he had also activated the deicing boots prior to the approach at Truckee. Additional Ground Witness Observations. There were five auditory witnesses to the accident. They all were located in the building next to the one with which the airplane collided. Upon hearing the collision they went outside and made the following statements regarding the weather conditions that they observed. One witness reported that the weather was a complete whiteout. It was snowing hard, and the visibility was zero. A second witness also reported it was snowing heavily and described it as a whiteout. He reported that he could see "quite a ways down the street," but visibility was poor looking up. He described the snow as being heavy and wet. A third witness also reported a storm had just come in and it was snowing heavily. He described it as a "wet, packed snow." Visibility was terrible, maybe about 40 feet. A fourth witness stated that it was snowing heavily and the snow was sticking. He could hardly see across the street. He estimated visibility at 100 yards. A fifth witness said she could not see across the street. The snow was not really wet and not really dry, but was sticking. Airplane Passenger Observations. The five airplane passengers reported the
The pilot's inadequate approach airspeed for the existing adverse meteorological conditions followed by his delayed remedial action to avert stalling and subsequent loss of airplane control. Contributing factors were the pilot's reduced visibility due to the inclement weather and the icing conditions.
Source: NTSB Aviation Accident Database
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