NTSB Factual Report

HISTORY OF FLIGHT

On December 21, 1997, at 0626 mountain standard time, a Beech A100, N100BE, operated by Aviation Charter, Inc., Eden Prairie, Minnesota, impacted terrain during a missed approach at the Colorado Springs Municipal Airport, Colorado Springs, Colorado. The commercial pilot and one passenger received fatal injuries, and the other passenger serious injuries. The aircraft was destroyed. The flight was operating in accordance with Title 14 CFR Part 135 and an IFR flight plan was filed. The flight originated from Flying Cloud Airport, Eden Prairie, Minnesota, at 0430, with a passenger stop at Minneapolis. All times are mountain standard time unless otherwise specified.

The flight was a charter carrying two Northwest Airlines mechanics to Colorado Springs, to repair a Northwest aircraft that had a mechanical problem.

The aircraft was conducting an instrument landing system (ILS) approach to runway 17L. The west local controller observed the aircraft fly into fog and controllers were then unable to contact the aircraft and it disappeared from radar. The aircraft was found by airport personnel approximately 31 minutes following the accident approximately 6,000 down runway 17L and 600 feet east of the runway. The delay in locating the aircraft was due to fog.

PERSONNEL INFORMATION

The pilot held commercial pilot certificate number 469841139, dated September 12, 1996, with ratings in single and multiengine land. He also held flight and ground instructor certificates bearing the same certificate number. He was certificated to conduct flight instruction in single and multiengine airplanes and instrument instruction in airplanes. He was certified to conduct advanced ground instruction and ground instrument instruction.

He held a first class medical certificate issued March 21, 1997, with no restrictions or limitations.

According to his employer, Aviation Charter, Inc., he had accumulated 3,400 hours of flight experience as a pilot with 1,900 hours as pilot-in-command (PIC). He had 2,100 hours of multiengine flight experience, 700 hours of which was as PIC. His experience in the accident aircraft make and model was 65 hours, all of which was as PIC.

Aviation Charter, Inc. provided information that the pilot had accumulated 160 flight hours in the 90 days preceding the accident, 46 of which were in the accident make and model aircraft. He had flown 50 hours in the preceding 30 days, with 10 hours in make and model and 3.5 hours, all in the accident make and model, the day of the accident.

The company also provided information that the pilot had accumulated 900 hours of night flight time and 500 hours of actual instrument time.

AIRCRAFT INFORMATION

The Beech A100 is a low wing, twin engine, turbo propeller powered, retractable tricycle landing gear aircraft with a maximum gross weight of 11,500 pounds. The accident aircraft, serial number B221, was manufactured in 1978 and had accumulated 8,651.2 hours of flight time. The last inspection was done 10.6 hours prior to the accident flight. Total fuel capacity on this aircraft was 470 gallons.

Two Pratt and Whitney PT6A-28 turbine engines, rated at 750 shaft horsepower each, powered the aircraft.

The cabin was configured with five individual seats, three of which were rear facing, a side-facing bench seat and a side-facing lavatory.

A partitioned cargo area, with cargo netting available, was installed in the cabin aft of the main entrance door.

The flight deck was configured for two pilots; however, the aircraft is certified for single pilot operation.

METEOROLOGICAL INFORMATION

Observed Colorado Springs weather at 0624 was 100 foot overcast skies, calm winds, and a temperature/dew point of 45 degrees Fahrenheit. At 0625, the pilot of N100BE was informed by ATCT that the RVR (runway visual range) on runway 17L was down to 1,800 feet and still deteriorating. Witnesses and the tower reported dense fog in the area at the time of the accident.

AIDS TO NAVIGATION

The primary navigation aid serving the facility is Black Forest VORTAC (very high frequency omnirange station with distance measuring equipment {DME}).

The pilot was cleared for an ILS DME approach to runway 17L. The decision height for the approach is 6,384 feet msl (200 feet above ground level) and the required RVR for a 14 CFR Part 135 flight to commence and approach is 2400 (1/2 mile). When on the glide slope, the decision height is 0.4 miles from the runway touchdown zone. A copy of the approach plate is attached.

COMMUNICATIONS

Transcripts of all pertinent communications are attached. They begin at 0617 when the pilot of N100BE reported on the Colorado Springs Terminal Air Traffic Control (ATCT) frequency while in a descent to an assigned altitude of 11,000 feet msl. The transcripts end at 0657, which is when Colorado Springs Municipal Airport operations personnel found the downed aircraft. Contact with the aircraft was lost at 0626.

The transcripts provide information that there was a misunderstanding on the part of the pilot of N100BE as to whether he was cleared for approach and landing to runway 17R or 17L, and information concerning the deteriorating visibility conditions. The air traffic controller working the flight pointed out these misunderstandings to the pilot.

AERODROME INFORMATION

Colorado Springs Municipal Airport is located at N38 48.3 and W104 42.0. on the east side of the city. Airport elevation is 6,184 feet above mean sea level (msl). The airport has three runways, 17L/35R, 17R/35L, and 12/30. It is served by both precision and non precision instrument approaches and has a low level wind shear alert system (LLWAS) installed, and (RVR) equipment for runways 35R and 17L.

Runway 17L, the runway used by the accident flight, is 13,500 feet in length, 150 feet in width, and is constructed of grooved concrete. The touchdown zone is 6,184 feet msl and the lighting consists of high intensity runway lights (HIRL), medium intensity approach lights with runway alignment indicator lights (MALSR), and a 3 degree slope precision approach path indicator (PAPI). There is 12,300 feet of runway remaining at the ILS touch down point.

WRECKAGE AND IMPACT INFORMATION

According to witness marks, the aircraft's first point of contact with the ground was approximately 6,500 feet south of the approach end of runway 17L displaced 613.8 feet east of the runway centerline. No evidence was found that the aircraft touched down on the runway. The wreckage scatter pattern was on a base course of 143 degrees and extended 427.5 feet from the initial impact point to where the fuselage came to rest oriented on a heading of 280 degrees. The fuselage was 736.9 feet east of the runway centerline where it came to rest, and the width of the debris pattern was 60 feet at the widest point with the most debris east of the scatter pattern base course. (Refer to the attached diagram).

The impact track started with a 12-foot long ditch-like gouge, which contained portions of the ventral fin. Some sheet aluminum, and what appeared to be fiberglass, was scattered along this path to a red lens light, which was located 45 feet from the initial impact point.

The horizontal and vertical stabilizers were located 53 feet along the scatter pattern displaced 15 feet west of the base course. They were intact and separation occurred at the forward portion of the base of the vertical stabilizer just aft of the aft pressure bulkhead. The horizontal stabilizer trim actuator measured 4 1/2 inches which, according to Beech Aircraft, corresponds to 2 degrees leading edge up.

Both propellers with their associated gearboxes and spinners separated from the aircraft and were located along the scatter pattern track.

The left propeller was found 115 feet down the scatter pattern and 15 feet west of the base track. The propeller blades exhibited forward bending, 'S' curves, leading edge scarring, and chordwise scratches on the blades. All blades remained in the hub.

The right propeller was located 120 feet down the scatter pattern and 35 feet east of the base track. It exhibited like damage as described concerning the left propeller.

The right wing separated from the aircraft at the outboard edge of the engine nacelle and was located 158 feet down the scatter pattern 12 feet east of the scatter pattern base track. The aileron and outer portion of the flap separated from the wing and were located adjacent to where the wing came to rest. The inboard flap remained attached to the right wing stub. The wing was devoid of fuel, except residual fuel, due to fuel cell compromise. Control continuity was intact within the wing. The right flap actuator measurements were: inboard 3 3/8 inches, which corresponds to 13 degrees; outboard 4 1/2 inches, which corresponds to 26 degrees of flap deflection.

The left wing remained attached to the aircraft. The engine remained attached to the wing, as did the flaps and aileron. The left wing flap actuators were measured at 2.0 inches on the inboard flaps and 15/16 inches on the outboard flaps. These measurements correspond to the flaps being in the up position, and control continuity was established within the wing. Residual fuel was found in the fuel cell, which was compromised by impact forces. The left engine propeller shaft was separated aft of the flange and bore evidence of tortional damage. Rotational damage was found in both the compressor and turbine sections of the engine and fuel was found in the lines, strainer, and fuel control. The left main landing gear was in the up position.

The inner portion of the right wing containing the engine nacelle and inboard flap remained attached to the fuselage. The engine remained partially attached to the mounts. The propeller shaft bore scarring opposite rotation at the flange, and both the compressor and turbine sections of the engine exhibited counter rotation damage. The inboard flap was extended 4.5 inches which, according to Beech engineering, equals a flap extension of approximately 25 degrees. Forces associated with the impact and breakup of the aircraft disconnected the flap drive at the fuselage junction point. The right main landing gear was in the up position.

The fuselage remained intact except the nose cone, which was found on the scatter pattern centerline 102 feet from the initial impact point. The left side of the nose and nose landing gear bay were crushed in and up and the nose section at the forward pressure bulkhead was distorted to the left. The nose landing gear was in the up position. The left cockpit area was crushed inward from the side and front and the area around the rudder pedals was crushed upward. The seat belt on the pilot's side was found to be severed during the on scene examination. The right side of the cockpit bore little evidence of distortion.

Documentation of the cockpit was as follows:

Overhead Panel

Windshield wiper between park and low Pilot instrument lights bright Master cockpit lights on Engine instrument lights on bright Pilot gyro lights on bright Instrument indirect lights on bright Radio panel lights on bright Copilot gyro lights on bright Overhead map light off Sub panel and console lights on medium Copilot instrument lights on medium

Lower Right Panel Landing gear handle up Propeller low pitch indicator CB popped Pressure bleed air valves closed Pressure decrease neutral Air ground switch ground Cabin temperature selector 1100 o'clock position Battery charger CB in Overhead lights CB popped Instrument indirect lights CB in Cabin lights CB in Gyro instrument lights CB popped Sub panel and pedestal lights CB popped Engine instrument lights CB popped Landing gear relay CB in

Radar Selector switch standby (With the selector switch in standby no other switch positions are pertinent.)

Radio and navigation equipment Digital and no useful information was retrieved.

Lower right CB panel

Cabin air CB popped Pressurization control CB in Left bleed air valve in Right bleed air valve CB popped Communications and navigation CB's in Phone audio CB in Propeller governor CB in T&SL CB in Flap and stabilizer CB in Avionics CB popped Communications 2 CB popped Yaw damper CB in Audio speaker CB in Propeller sync CB in Enunciator panel CB in Windshield wiper CB in Landing gear warning CB in The remaining CB's on the lower right CB panel were in.

Cabin altitude was set at 7,000 feet and aircraft altitude on the Cabin pressure instrument was at 2,000 feet

Pitch trim main switch was in the on position. Standby was neutral. Power Quadrant (Center Console) Power levers full forward Propeller levers full forward Condition levers bottom of yellow band Aileron tab neutral Flap handle the flap handle was in the full down position. Flap position gauge needle at the 1000 o'clock position Cabin pressure differential pressure 2.4 psi Cabin altitude needle at the 100 o'clock position Fire detection test switch off Right instrument panel Airspeed 0 Artificial horizon in excess of 20 degrees nose up and at 20 degrees right wing down Altimeter 6,540 feet @ 30.12 Course deviation indicator 300 degrees needles centered Radio magnetic indicator 295 degrees Vertical speed indicator 700 feet up Turn and bank indicator needle centered, ball full left Cabin air 0

Lower right side panel Gyro suction needle at the 0800 o'clock position Pneumatic pressure 0 Oxygen supply pressure 1,600 psi Hobbs meter 1484.4 hours Pilot's static air source normal (safety guard in place)

Lower left forward panel (outboard) Battery off Generator 1 off Generator 2 off Inverters unreadable Ignition and engine start unreadable Left voltmeter 0 Right voltmeter 0 De-ice amps 0 Defrost air on Left side panel Left firewall fuel valve on Right firewall fuel valve on Left firewall valve CB popped Standby pump CB popped Left aux. transfer CB in Left fuel pressure warning CB in Left fuel quantity CB in Crossfeed valve CB in Right fuel quantity CB in Right fuel pressure warning CB in Right aux. transfer CB in Right standby pump CB in Right firewall valve CB in Left standby pump off Left transfer pump off Left fuel gauge

NTSB Probable Cause

Failure of the pilot to follow IFR Procedures and maintain the minimum descent altitude (MDA). A related factor was fog.