Colorado

During the instructional flight, the instructor shut down the right engine and feathered the propeller. It was subsequently restarted, but the left engine started running rough and began to vibrate. The left engine was shut down and the propeller feathered. Level flight was maintained from power produced by the right engine. The left engine was then restarted but instead of producing thrust, the engine produced more drag so it was secured again. Then the right engine began losing power. Full power was applied but the airplane continued to descend. The instructor lowered the landing gear and while in-transit, the airplane clipped the tops of trees. He was able to guide the airplane between two houses and impacted an open field. The airplane bounced across the road, struck a power pole, and caught fire. The two pilots evacuated the airplane via the main cabin door. Examination at the airport of departure disclosed two pools of oil at the approximate positions of the two engines. There were two trails of oil leading from the parking spot down the taxiway and onto the runway. Both engines were partially disassembled and examined. There was evidence that both engines had failed catastrophically due to oil starvation. The left engine crankshaft was broken and all the piston heads were at the tops of their cylinders. Pieces of metal were recovered from the right engine oil sump. According to the operator, the engine rocker box recovery system must be drained during preflight to avoid hydraulic lock. The instructor stated that when they preflighted the airplane, the drain valves were open (the drained oil is captured and recycled). He thought they had closed both valves. According to the operator, either the pilot's failed to close the drain valves or they were jammed in the open position. The operator said the latter was unlikely "because you can feel it move when you close it."

According to the pilot, passenger, and several witnesses, during takeoff the light jet became airborne momentarily, and then banked aggressively to the left. It impacted the runway in a left wing low attitude and cartwheeled down the runway. An examination of the airplane's systems revealed no anomalies. Approximately 1.5 minutes before the airplane was cleared for takeoff, a De Havilland Dash 8 (DH-8) airplane departed. A wake turbulence study conducted by an NTSB aircraft performance engineer concluded that even slight movement in the atmosphere would have caused the circulation of the vortices near the accident site to decay to zero within two minutes, that is, before the time accident jet would have encountered the wake from the DH-8. The study states, in part: "Given the time of day of the accident, consistent reports of easterly surface wind speeds on the order of 6 to 7 knots, higher wind speeds aloft, and the mountainous terrain near Colorado Springs, it is unlikely that the atmosphere was quiescent enough to allow the wake vortices near the Sport-Jet to retain any significant circulation after two minutes. Furthermore, easterly surface winds would have blown the wake vortices well to the west of the runway by the time of the accident. Consequently, while in smooth air the wake vortices from the DH-8 that preceded Sport-Jet off of the runway may have retained enough circulation after two minutes to produce rolling moments on Sport-Jet on the order of the rolling moment available from the Sport-Jet's ailerons, it is most likely that the wake vortices were neither strong enough nor close enough to the Sport-Jet to cause the violent roll to the left reported by the pilot and witnesses to the accident."

During an ILS approach in night instrument meteorological conditions, the airplane impacted terrain and was destroyed by impact forces and post crash fire. Prior to departure, the pilot obtained a weather briefing, which reported light rain, mist, and instrument meteorological conditions at the destination airport. After approaching the terminal area, the pilot received radar vectors to intercept the localizer for the Runway 35R ILS approach. The pilot's keying of the microphone and the timing of his speech exhibited decreased coordination during the approach phase of flight. After crossing the outer marker and at altitude of 7,700 feet, the pilot asked the controller what the current ceilings were at the airport, and the controller stated 500 feet. With the airplane at an altitude of 6,800 feet, the controller informed the pilot of a "low altitude alert" warning, at which the pilot responded, "Yeah, I am a bit low here." Approximately 20 seconds later, the pilot stated, "I'm back on glideslope." No further communications were received from the accident airplane. The controller issued another low altitude warning, and the radar target was lost. The accident site was located on a hilly, grass field at an elevation of 6,120 feet approximately 2.6 nautical miles from the runway threshold
near the extended centerline of the runway. At 2027, the weather conditions at the airport were reported as wind from 360 degrees at 10 knots, visibility 2 statute miles with decreasing rain, scattered clouds at 500 feet, broken clouds at 1,100 feet, and an overcast ceiling at 2,800 feet. An acquaintance of the pilot, who had flown with him on other occasions, provided limited information about the pilot's proficiency, but stated, "a night ILS in IFR conditions would not be [the pilot's] first choice if he had an option." The pilot's logbooks were not located. The pilot did not hold a valid medical certificate at the time of the accident, and postaccident toxicological test revealed the presence of unreported prescription medications. No anomalies were noted with the airframe and engines. Ground inspection and flight testing of the airport's navigational equipment revealed that the equipment functioned satisfactorily.

The commercial pilot was executing a precision instrument approach at night in instrument meteorological conditions when the airplane collided with terrain about four miles short of the runway. A review of air traffic control communications and radar data revealed the pilot was vectored onto the final approach course but never got established on the glide slope. Instead, he made a controlled descent below the glide slope as he proceeded toward the airport. When the airplane was five miles from the airport, a tower controller received an aural low altitude alert generated by the Minimum Safe Altitude Warning (MSAW) system. The tower controller immediately notified the pilot of his low altitude, but the airplane collided with terrain within seconds. Examination of the instrument approach system and onboard flight navigation equipment revealed no pre-mishap anomalies. A review of the MSAW adaptation parameters revealed that the tower controller would only have received an aural alarm for aircraft operating within 5 nm of the airport. However, the frequency change from the approach controller to the tower controller occurred when the airplane was about 10.7 miles from the airport, leaving a 5.7 mile segment where both controllers could receive visual alerts, but only the approach controller received an aural alarm. A tower controller does not utilize a radar display as a primary resource for managing air traffic. In 2004, the FAA changed a policy, which eliminated an approach controller's responsibility to inform a tower controller of a low altitude alert if the tower had MSAW capability. The approach controller thought the MSAW alarm parameter was set 10 miles from the airport, and not the 5 miles that existed at the time of the accident. Subsequent investigation revealed, that The FAA had improperly informed controllers to ensure they understood the alarm parameters for control towers in their area of responsibility. This led the approach controller to conclude that the airplane was no longer her responsibility once she handed it over to the tower controller. Plus, the tone of the approach controller's aural MSAW alarm was not sufficient in properly alerting her of the low altitude alert.

A witness saw the airplane approach from the east. She said that the airplane came in "pretty fast" and touched down "approximately half way down the runway." The witness said, "The nose was down. He hit the ground and within 3 seconds he was off the runway and gone. Then all you saw was smoke." The witness said when the airplane hit "the front end shook. It wobbled like a kid on a tricycle. When it shook, it kind of looked like it [the airplane] bounced. Then it was gone." The control tower operator said he heard the captain say something over the radio, which caused him to look in the direction of the airplane. The tower operator saw the airplane off the runway, the main landing gear came off behind the airplane, and the airplane caught fire. The tower operator said he saw four people get out of the airplane. The airplane came to rest in a shallow ravine approximately 331 feet north of the runway. An examination of the airplane showed impact damage to the nose gear and nose gear wheel well. An examination of the airplane's systems revealed no anomalies.

On February 16, 2005, about 0913 mountain standard time, a Cessna Citation 560, N500AT, operated by Martinair, Inc., for Circuit City Stores, Inc., crashed about 4 nautical miles east of Pueblo Memorial Airport, Pueblo, Colorado, while on an instrument landing system approach to runway 26R. The two pilots and six passengers on board were killed, and the airplane was destroyed by impact forces and post crash fire. The flight was operating under the provisions of 14 Code of Federal Regulations Part 91 on an instrument flight rules flight plan. Instrument meteorological conditions prevailed at the time of the accident.

The pilot's father had just purchased the airplane for his daughter, and she was receiving model-specific training from a contract flight instructor. Her former flight instructor was aboard as a passenger. The engines were started and they quit. They were restarted and they quit again. They were started a third time, and the airplane was taxied for takeoff. Shortly after starting the takeoff roll, the pilot reported an unspecified engine problem. The airplane drifted across the median and parallel runway, then rolled abruptly to the right, struck the ground, and cartwheeled. The landing gear was down. Neither propeller was feathered. Disassembly of the right engine and turbocharger revealed no anomalies. Disassembly and examination of the left engine and turbocharger revealed the mixture shaft and throttle valve in the throttle and fuel control assembly were jammed in the idle cutoff and idle rpm positions, respectively. Manifold valve and fuel injector line flow tests produced higher-than-normal pressures, indicative of a flow restriction. Disassembly of the manifold valve revealed the needle valve in the plunger assembly was stuck in the full open position, collapsing the needle valve spring. A scribe was used to free the needle valve, and the manifold valve and fuel injector lines were again flow tested. The result was a lower pressure. Plunger disassembly revealed the threads had been tapped inside the retainer and metal shavings were found between the retainer and spring. The Teledyne Continental Motor (TCM) retainer has no threads. GPS download showed that 2,698 feet had been covered between the start of the takeoff roll and the attainment of rotation speed. Maximum speed attained was 132 mph. Computations indicated distance to clear a 50-foot obstacle was 2,000 feet, distance to clear a 50-foot obstacle (single engine) was 2,600 feet, and accelerate-stop distance was 3,000 feet.

Shortly after takeoff, the pilot reported to air traffic control he needed to return to the airport to land. The controller asked the pilot if he required any assistance, and the pilot responded, "negative for right now uh just need to get in as soon as possible." The controller then asked the pilot what the problem was, in which the pilot responded, "stand by one minute." Approximately 30 seconds later and while the airplane was on a left downwind to runway 35R, the pilot stated he was declaring an emergency and "...we've got an air an engine ta shut down uh please roll the equipment." The controller and other witnesses observed the airplane on the base leg and then overshoot the final approach to runway 35R. After observing the airplane overshoot the final approach, the controller then cleared the pilot to the next runway, runway 28, and there was no response from the pilot. The controller observed the airplane's landing lights turn down toward the terrain, and "the MU2 was gone." A witness observed the airplane make an "immediate sharp bank to the left and descend to the ground. The impact appeared to be just less than a 45 degree angle, nose first." A performance study revealed that while the airplane was on downwind, the airplane started to bank to the left. The bank angle indicated a constant left bank angle of about 24 degrees as the airplane turned to base leg. Twenty-three seconds later, the bank angle began to increase further as the airplane turned to final approach, overshooting the runway, while the angle of attack reached stall angle of about 17 degrees. The flight path angle then showed a decrease by 22 to 25 degrees, the calibrated airspeed showed a decrease by 40 to 70 knots, and the vertical speed indicated a 3,000 feet per minute descent rate just before impact. Examination of the airframe revealed the flaps were in the 20 degree position, and the landing gear was retracted. According to the airplane flight manual, during the base leg, the flaps should remain in the 5 degree position and the landing gear extended; and when landing is assured, the flaps then extended to 20 degrees and maintain 125 knots calibrated airspeed (KCAS) during final and 110 KCAS when over the runway. Minimum controllable airspeed (Vmc) for the airplane is 99 KCAS. Examination of the propellers revealed that at the time of impact, the left propeller was in the feathered position and the right propeller was in the normal operating range. Examination of the left engine revealed static witness marks on several internal engine components, and no anomalies were noted that would have precluded normal operation. The reason for the precautionary shutdown of the left engine was not determined. Examination of the right engine revealed rotational scorring and metal spray deposits on several internal engine components. Four vanes of the oil pump transfer tube were separated and missing. The gearbox oil-scavenge pump was not free to rotate and was disassembled. Disassembly of the oil-scavenge pump revealed one separated oil pump transfer tube vane was located in the pump. Pitting and wear damage was noted on all of the roller bearing elements and the outer bearing race of the propeller shaft roller bearing. No additional anomalies were noted.

On November 28, 2004, about 0958 mountain standard time, a Canadair, Ltd., CL-600-2A12, N873G, registered to Hop-a-Jet, Inc., and operated by Air Castle Corporation dba Global Aviation as Glo-Air flight 73, collided with the ground during takeoff at Montrose Regional Airport (MTJ), Montrose, Colorado. The on-demand charter flight was operated under the provisions of 14 Code of Federal Regulations (CFR) Part 135 on an instrument flight rules (IFR) flight plan. Instrument meteorological conditions prevailed, and snow was falling. Of the six occupants on board, the captain, the flight attendant, and one passenger were killed, and the first officer and two passengers were seriously injured. The airplane was destroyed by impact forces and post crash fire. The flight was en route to South Bend Regional Airport (SBN), South Bend, Indiana.

The captain reported that he obtained weather briefings prior to and during the flight. The briefings did not include any NOTAMS indicating a contaminated runway at their destination airport. The captain obtained a report from the local fixed base operator that a Learjet had landed earlier and reported the runway as being okay. The tower was closed on their arrival, so they made a low pass over the airport to inspect the runways. Based on the runway and wind conditions, they decided their best choice for landing was on runway 08L. The captain said the landing was normal and the airplane initially decelerated with normal braking. As they encountered snow and ice patches, the captain said he elected to deploy the thrust reversers. The captain said that as the thrust reversers deployed, the airplane began to yaw to the left and differential braking failed to realign the airplane with the runway. The captain said the airplane departed the left side of the runway and rotated counter clockwise before coming to rest on a southwesterly heading. A witness on the airport said, "I watched them touch down. I heard the [thrust] reversers go on and then off, and then on again. As they came back on for the second time, that's when the plane started making full circles on the runway. This happened two, maybe three times before going off the side of the runway." The airplane's right main landing gear collapsed on departing the runway, causing substantial damage to the right wing, right main landing gear and aft pressure bulkhead. At the accident site, the right engine thrust reverser was partially deployed. The left engine thrust reverser was fully deployed with the blocker doors extended. An examination of the airplane revealed a stuck solenoid on the right engine thrust reverser. No other system anomalies were found. Approximately 33 minutes prior to the accident, the pilot requested from Denver Air Route Traffic Control Center, the weather for the airport. Denver Center reported the conditions as "winds calm, visibility 6 miles with light mist, 3,000 overcast, temperature zero degrees Centigrade (C) dew point -1 degree C, altimeter three zero 30.20, and there was at least a half inch of slush on all surfaces." The pilot acknowledged the information. The NOTAM log for the airport showed that at 2115, the airport issued a NOTAM stating there was "1/2 inch wet snow all surfaces." The airport operations manager reported that at the time of the accident the runway surface was covered with 3/4 inch of wet snow. The airport conducts a 24 hour, 7 days a week operation; however, operations support digresses to fire coverage only after 2300.