TALKEETNA, AK, USA
N1589F
Cessna 185E
The pilot departed on a U.S. Government flight for the Department of Interior, National Parks Service, with three park rangers, in a wheel/ski equipped airplane. The airplane was operated as a VFR, on-demand air taxi flight to the Denali National Park base camp, located at 7,200 feet msl on the Kahiltna glacier. The base camp is where the three rangers were to begin mountain patrol operations on Mt. McKinley, Alaska. Variable weather conditions with low ceilings near the base camp made landing at the base camp problematic throughout the day. When the pilot departed for the base camp, he opened a VFR flight plan, and was advised that an AIRMET for mountain obscuration and turbulence were current for the area. About 45 minutes after departure, the pilot talked via radio to another airplane pilot at the Kahiltna base camp, who advised the upper portion of the glacier was closed due to low clouds. The accident pilot commented that the weather had closed the lower portion of the glacier, and he was diverting toward the west, toward another glacier drainage. A ranger on-board the accident airplane contacted his ranger station by a hand-held radio and stated the flight was returning. The accident airplane did not return to its base, and was reported overdue. The wreckage was located the following day, scattered over about 1/2 mile. Evidence indicated the airplane broke apart in-flight. The left wing, left wing lift strut, the left landing gear strut, the left door and windshield, were located on the upper portion of a steep hillside. The engine struck the ground below the left wing, separating the propeller, and then tumbled downhill. The fuselage came to rest about 1/4 mile below the left wing, and was consumed by a postcrash fire. The airplane's wing spars, and each horizontal stabilizer had all negative bending signatures. The flap handle was found extended to 20 degrees. The airplane manufacturer does not publish any negative structural load factors for a flaps down configuration. A review of meteorological data revealed an occluded front with convective activity that progressed northward toward the accident area, accompanied by heavy rain and hail. The front was positioned near the accident area when the airplane was diverting away from the mountain. The pilot was the chief pilot for the operator. The director of operations for the company has the responsibility of operational control for the operator.
HISTORY OF FLIGHT On June 19, 2000, about 1815 Alaska daylight time, a wheel/ski equipped Cessna 185E airplane, N1589F, was destroyed when it broke-up in flight over a remote area of the Denali National Park and Preserve, about 52 miles west of Talkeetna, Alaska. The airplane was being operated as a visual flight rules (VFR) U.S. Government flight by the U.S. Department of Interior, National Parks Service (NPS), Talkeetna, Alaska, when the accident occurred. The airplane, provided by Hudson Air Service Inc., Talkeetna, was utilized on an on-demand Title 14, CFR Part 135 flight. The airline transport certificated pilot and the three passengers received fatal injuries. A VFR flight plan was filed. The flight originated at the Talkeetna airport at 1710. The flight was conducted to transport a National Park Service ranger, and two volunteer rangers, to the Denali National Park base camp, located at 7,200 feet msl on the southeast fork of the Kahiltna glacier, about 48 miles northwest of Talkeetna. The three rangers were to begin mountain patrol operations on Mt. McKinley. The director of operations for the operator reported that variable weather conditions near the National Park Service's base camp made landing at the base camp problematic throughout the day of the accident. The accident pilot had flown a company Cessna 172 over the areas of the Ruth and Tokositna glaciers between about 0950 and 1050. When he departed Talkeetna at 0947 in the Cessna 172, a flight service station specialist at the Federal Aviation Administration (FAA), Talkeetna Flight Service Station (FSS), opened a VFR flight plan for the flight, and gave the pilot an advisory that stated, in part: "AIRMET for mountain obscuration and turbulence are current for Cook Inlet, and Susitna Valley..." The director of operations reported that before departing on the accident flight, the pilot commented he would wait to see if conditions improved during the day near the Kahiltna base camp before canceling the flight for the National Park Service. The pilot filed a VFR flight plan with the Talkeetna FSS, and departed Talkeetna at 1710, headed for the Kahiltna base camp in the accident airplane. When the pilot filed his flight plan, the FSS specialist included an advisory that stated, in part: "...still an AIRMET for low altitude turbulence, let me know if you need details." The National Park Ranger on board, contacted the Talkeetna Ranger Station by a hand-held radio about 1710, and reported that he would be unable to do any flight following during the flight, but he would contact the ranger station when the airplane landed at the Kahiltna base camp. After departure, at 1714, the accident airplane pilot talked via radio to another airplane pilot (N70176) about conditions in the area of the Kahiltna base camp. The radio conversation was recorded at the Talkeetna FSS. The accident pilot asked: "...you haven't heard anybody talking about getting up to the base camp have you?" The pilot of N70176 replied: "No, I was in on the Ruth (glacier) and that is open at the moment, but looking from Moose's Tooth (peak) over south Hunter (pass), looked like it was closed, and I haven't heard anything about the Kahiltna." About 1757, the ranger on board the accident airplane contacted the Talkeetna ranger station by a hand-held radio and stated the flight was returning to Talkeetna from the area of the Kahiltna icefall. The pilot of a McKinley Air Service airplane landed at the Kahiltna base camp in the afternoon of the accident. The pilot reported that due to a dead battery, she did not depart the base camp until about 1800, heading for Talkeetna. As she proceeded southbound, she said the accident airplane pilot contacted her via radio and reported low clouds over the Kahiltna glacier icefall, and said he was returning to Talkeetna. The McKinley Air pilot also observed low weather conditions over the icefall and headed back to the base camp. The accident airplane pilot again called the McKinley Air pilot and reported that the weather conditions had closed in over the Big Bend of the Kahiltna glacier (lower on the mountain, south of the base camp). He also reported that the Pica glacier (east of the Kahiltna glacier) area was closed, but he could see light on the Lacuna glacier (west of the Kahiltna glacier), and was going to head toward that location. The McKinley Air pilot responded by saying that attempting to proceed to the Kahiltna base camp was not an option. This was the last radio transmission received from either the accident airplane pilot or passengers. The McKinley Air pilot then landed at the base camp where the airplane and passengers remained overnight due to fog and snow showers. The McKinley Air pilot said that the wind was very light, with no turbulence. The accident airplane did not arrive in Talkeetna, and was reported overdue at 1955. The wreckage was located on June 20, 2000, at 1617, by search aircraft. An Alaska State Trooper helicopter landed below the accident site and verified the identity of the wreckage. The accident occurred during the hours of daylight at latitude 62 degrees, 42.489 minutes north, and longitude 151 degrees, 45.385 minutes west. PERSONNEL INFORMATION The pilot was the chief pilot for the operator. He held an airline transport pilot certificate with a multiengine rating. He also held a commercial pilot certificate with airplane single-engine land, and single engine sea ratings. The most recent second-class medical certificate was issued to the pilot on April 18, 2000, and contained no limitations. The aeronautical experience listed on page 3 of this report was obtained from a review of information from the operator. According to the operator's records, the pilot's total aeronautical experience consisted of about 9,095 hours, of which about 2,000 were accrued in the accident airplane make and model. In the preceding 90 and 30 days prior to the accident, the pilot flew a total of 142 and 108 hours, respectively. The pilot's normal scheduled duty day was from 0800 to 2200. In the three days prior to the accident, the pilot was off duty on June 17. On June 18, he flew 6.25 hours. On the accident date of June 19, he flew 3.0 hours. The pilot was hired by the operator on March 13, 1995. His most recent company recurrent training was completed on February 6, 2000. Some of the training topics covered in the operator's training manual include mountain flying, and glacier operations. The pilot's most recent FAA Part 135.293, and Part 135.299, airman competency/proficiency check was conducted on April 18, 2000, in a Cessna 172. The pilot received an interagency pilot evaluation/qualification recurrent check from a Department of the Interior, Office of Aircraft Services inspector, on April 25, 2000, in a Cessna 185. The operator holds an on-demand air taxi certificate. The company's management personnel include the director of operations, the chief pilot, and the director of maintenance. The duties, responsibilities, and authority, listed in the operator's operations manual, for the director of operations, include: Ensure the safe and organized operation of the company; ensure that company aircraft are airworthy; train and instruct company personnel in their specific duties; responsible for the safe operation and oversight of aircraft and company personnel; acts as the representative of the company; may dispatch and cancel flights; and is the final authority for company operations, policies, aircraft, pilots, and ground personnel. The chief pilot duties, responsibilities, and authority, include: Ensure that company pilots operate within the FAA's and company's policies; conduct pilot training and ensure they conduct themselves in a professional manner; ensure that pilot records are current; and may dispatch flights in accordance with the company training program. The director of maintenance duties, responsibilities, and authority, include: Schedule/perform required maintenance and inspections; keep the maintenance records up-to-date, including pilot notification forms and ADs; notify the director of operations of any mechanical irregularities; act as the company maintenance representative between the FAA and the company; remove from, or return company aircraft to service; and may operate company aircraft on the ground. In the Pilot's Responsibilities and Procedures section of the company operations manual, it includes, among others, the requirement that before flight, the pilot-in-command shall ensure the required airworthiness inspections have been made. This can be accomplished by a review of the Pilot's Notification sheet that is maintained for each company airplane. In the operational control section of the company operations manual, it includes the following: "The director of operations will have the responsibility for operational control. If the director of operations is not available, he may delegate this responsibility to the chief pilot, or the director of maintenance. In such a case, the delegated person must be notified of each and every flight that occurs. If, for any reason, the PIC (pilot-in-command) of a flight feels that the flight cannot be conducted or completed, he has the right to turn down, or cancel the flight." AIRCRAFT INFORMATION At the time of the accident, the airplane had accrued a total of 7,130.4 hours. The airplane was maintained on an approved aircraft inspection program (AAIP). The AAIP has four inspection cycles that are scheduled every 50 hours. Each inspection cycle may be completed within 10 hours before, to 10 hours after, the anticipated 50 hour cycle. The completion of all four cycles qualifies as an annual inspection. The latest four cycle inspection was completed on December 3, 1999. Examination of the maintenance records revealed that the most recent inspection cycle was number three, accomplished on May 28, 2000, at an hour reading of 1133. At the accident site, the recording hour meter within the airplane's tachometer was indicating 1204.9, which is 11.9 hours beyond the required inspection time. The engine had accrued a total time of 1,684 hours. The maintenance records note that a major overhaul was accomplished on August 13, 1998, 516.9 hours before the accident. The airplane's wheel/ski assemblies, Fluidyne model C-3600, were installed on the airplane on October 10, 1999. The wheel/ski assemblies utilize a coiled spring/cable and a second safety cable attached to the tip of each ski, and a separate safety cable attached to the trailing end of each ski. The operator reported that during flights to and from the Kahiltna glacier area, no radar coverage is available, and the radar transponder is not utilized. The airplane was equipped for basic instrument flight which, among others, included an attitude indicator, a heading indicator, a rate of turn indicator, and a vertical speed indicator. The airplane was equipped with a Robertson Aircraft Corporation, Short Takeoff and Landing (STOL) modification that was installed under supplemental type certificate (STC) SA1441WE on April 16, 1969. The Robertson STOL STC is currently owned by Sierra Industries Inc., Uvalde, Texas. The Robertson STOL modification on the accident airplane, incorporated a contoured wing leading edge, upper wing surface stall fences, a filler strip between the trailing edge of the wing and the ailerons, and the ability of the ailerons to droop as the flaps are extended. The amount of aileron droop, as the flaps are extended, is as follows: Flaps zero; Ailerons are at zero degrees, plus or minus 2 degrees. Flaps at 10 degrees; Ailerons are at 8 degrees, plus or minus 2 degrees. Flaps at 20 degrees; Ailerons are at 13 degrees, plus or minus 2 degrees. Flaps at 30 degrees; Ailerons are at 15 degrees, plus or minus 2 degrees. Flaps at 40 degrees; Ailerons are at 12.5 degrees, plus or minus 2 degrees. According to Sierra Industries personnel, the Cessna 185 wing design, and the utilization of the Robertson STOL modification incorporating a contoured wing leading edge, does not alter the chordwise or spanwise pressure distribution, nor does it change the wing aerodynamic center. Its sole function is to increase the angle of attack range over which the wing stalls, making the stall characteristic very docile. In addition, the modification does not change the flaps up, or flaps down, lift/drag ratio, control capabilities, or the airplane's handling qualities. According the Cessna Aircraft Company, the following airspeed limitations are listed in the owner's manual: Maximum airspeed (Vne), 210 MPH; Maximum structural cruising speed (Vno), 170 MPH; Maneuvering speed (Va), 138 MPH; Maximum speed, flaps extended (Vfe), 110 MPH. The airframe flight load factors, for flaps up; 3.8 positive to 1.52 negative. The flight load factor for flaps down; 3.5 positive. No negative load factor is listed for flaps down. The manufacturer indicated that the design load factors are 150 percent of the flight load factors, and in all cases, the structure meets or exceeds design loads. METEOROLOGICAL INFORMATION On June 19, 2000, at 1753, an Aviation Routine Weather Report (METAR) from Talkeetna was reporting, in part: Wind, 220 degrees (true) at 13 knots, gusts to 21 knots; visibility, 10 statute miles; clouds and sky condition, 2,500 feet scattered, 4,100 feet broken, 4,900 feet overcast; temperature, 55 degrees F; dew point, 44 degrees F; altimeter, 29.68 inHg; remarks, pressure rapidly rising. At 1553, a METAR from Skwentna, Alaska, located 47 miles south-southeast of the accident site, was reporting, in part: Wind, 170 degrees (true) at 6 knots; visibility, 20 statute miles in light rain; clouds and sky condition, 2,500 feet broken, 6,000 feet broken, 10,000 feet overcast; temperature, 55 degrees F; dew point, 50 degrees F; altimeter, 29.69 inHg. At 1654, a METAR from Chulitna, Alaska, located 54 miles east of the accident site, was reporting, in part: Wind, calm; visibility, 40 statute miles; clouds and sky condition, 6,000 feet broken, 10,000 feet overcast; temperature, 55 degrees F; dew point, 34 degrees F; altimeter, 29.66 inHg; remarks, breaks in the overcast, all quadrants. A National Weather Service forecast for the Denali Park area, issued on June 19 at 1130, stated, in part: "This afternoon, mostly cloudy. Scattered areas of light rain. South winds gusting to 30 mph in channeled areas." A National Park Service ranger at a camp at 14,200 feet on Mt. McKinley reported that between 1700 and 1900, the weather conditions included a visibility of 1/2 mile in light snow, and a 0 to 5 knot wind from the south. The pilot of the airplane at the Kahiltna base camp that talked with the accident pilot, and a National Park Service ranger who was camped about two miles south of the Kahiltna base camp, both reported the weather conditions included low clouds, scattered snow showers, and fog. The owner of the Angle Haven Lodge, located along the Yentna River, 31 miles south of the accident site, reported that about 1800, he and several of his clients were fishing next to the lodge. He saw a large wall of cumulus clouds approaching from the south. The wall of clouds was preceded by high winds. The storm contained extremely heavy rain, the heaviest rain the owner had ever observed. The storm was fast moving, proceeding from the south to the north, toward the base of the Alaska Range. The storm lasted about 1 to 1 1/2 hour. A weather study was conducted by an NTSB senior meteorologist. All times in the study are Alaska daylight time. The weather study noted the National Weather Service's 0305 synoptic report stated, in part: "...an occluded front across the Kuskokwim Delta, the Kuskokwim Valley, northern Cook Inlet and Prince William Sound, will dissipate over the Tanana Valley, lower Yukon Valley, and the Yukon-Kuskokwim Delta on Monday." The 0859 synoptic report stated, in part: "...a cold upper low in the vicinity of King Salmon will continue to drift northeast toward the Cook Inlet today. An air mass across south central and southwest Alaska, is increasingly unstable as cold air aloft phases with maximum after
The pilot's continued flight into known adverse weather conditions and subsequent in-flight break-up. Factors in the accident were weather conditions consisting of low ceilings, turbulence, and an occluded front with convective activity, and inadequate oversight of the flight by company management.
Source: NTSB Aviation Accident Database
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