FTW95FA004

NTSB accident investigation · Beech 1900D · Denver, CO · October 2, 1994

Accident · Minor injuriesField investigationFinal report
Date
October 1, 1994, 18:05 local (Oct 2, 1994, 00:05 UTC)
Place
Denver, CO
Injuries
1 minor, 17 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N31YVBeech 1900D
Weather
Instrument (IMC) · Day
Status
Completed · report May 18, 1995
Report
Approved by Office Director
Case key
19190

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

The captain's inaccurate evaluation of weather conditions, and his decision to fly into known adverse weather. A factor was the hail.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

In flight encounter with weatherClimb - to cruise
Weather evaluation - inaccuratePilot in commandCause
Flight into known adverse weather - initiatedPilot in commandCause
Weather condition - hailFactor
Airframe/component/system failure/malfunctionClimb - to cruise
Window,flight compartment window/windshield - disintegrated

Analysis

As the level 6 thunderstorm passed over the airport from northwest to southeast, the captain elected not to take off because of the falling hail. After waiting about 30 minutes, the flight took off on runway 35L. The captain requested a right turn, and was assigned a heading of 080 degrees and cleared to climb to 20,000 feet. The airplane entered the overcast and encountered 'light hail.' As it turned onto its assigned heading, the airborne weather radar indicated heavy precipitation ahead. A request was made for a turn further right. Suddenly, the right windshield shattered, sending glass particles into the first officer's eyes. The airplane immediately descended to visual meteorological conditions, returned to the airport, and landed.

Factual narrative

History of flight

On October 1, 1994, approximately 1805 mountain daylight time, a Beech 1900D, N31YV, was substantially damaged during an inflight encounter with adverse weather near Denver, Colorado. There were no injuries to the captain and 16 passengers, but the first officer sustained minor injuries. Instrument meteorological conditions prevailed.

The following is based on interviews with the captain and first officer, and the pilot/operator report. The airplane, flight 7658, operated by Mesa Airlines, Inc., d/b/a United Express, taxied to runway 35L at 1720, but was placed in the "penalty box" due to weather causing a traffic backlog. It began to rain heavily and several wind shear alerts were issued. When the flight was cleared to taxi onto the runway, the captain declined and decided to wait for better weather conditions. Hail began to fall and the right engine was shut down to conserve fuel. A Boeing 727, later identified as United Air Lines flight 898, took off at 1748 and turned to the left. Shortly thereafter, at 1750, the United pilot advised the control tower that traffic should avoid a westerly departure. The captain said the pilot sounded "thoroughly shaken." When weather conditions improved and the crew noted no precipitation echoes on the weather radar through various tilt angles, flight 7658 took off at 1759.

Because of the previous pilot report, the captain requested a right turn after departure. The flight was assigned a heading of 080 degrees and an altitude of 20,000 feet. The airplane entered the overcast and it began to rain, followed by "light hail." As the airplane was approaching 10,000 feet, the airborne weather radar indicated heavy precipitation ahead, and the crew requested a turn further to the right. The airplane then encountered heavy hail and the right windshield "exploded," sending glass particles into the first officer's eyes and temporarily blinding him. After telling air traffic control what had happened, the flight was cleared to land on any runway. The captain descended into visual meteorological conditions and landed on runway 26R.

Meteorological information

The captain said that he personally obtained a weather briefing via computer prior to departure. The reports indicated that visual meteorological conditions prevailed in Denver, Amarillo, and along the route. He said the weather reports were not "real time," but were probably at least one hour or more old. Asked why his dispatcher did not provide him with more timely weather information, the captain replied that his company operated under Federal Aviation Regulations Part 135 and did not have a dispatch office. Obtaining weather reports and filing flight plans was done by the flight crew.

Weather and air traffic control studies were made by the Safety Board's Operational Factors Division. These reports are attached as exhibits.

Flight recorders

Both cockpit voice and flight data recorders were removed from the airplane and were examined by the Safety Board's Engineering and Computer Services Division. No extraordinary data was retrieved from the flight data recorder. The ATC communications channel on the cockpit voice recorder was found to have been wired incorrectly when it was installed by the airplane manufacturer. No cockpit communications transcript was made.

Aircraft

Registration
N31YV
Reported as
Beech 1900D
Category
Airplane
Serial number
UE-31
Airframe hours
4,723
Engine
P&W PT6A-67D, turbo prop
Damage
Substantial damage
Flight
Part 135
Registered owner
Mesa Airlines, Inc.
Airworthiness certificate
Standard, Transport
Last inspection
Continuous airworthiness · September 26, 1994 · 44 hours before
Departed
DEN · CO
Destination
AMA · Amarillo, TX
Flight plan
IFR

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
35
Certificates
Commercial, Airline transport
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--no waivers/lim.
Seat
Left
Flight hours
6,921 total · 1,859 in this make and model · 4,786 as pilot in command · 266 in the last 90 days · 96 in the last 30 days · 8 in the last 24 hours

Weather

Conditions
Instrument (IMC) · Day
Wind
310° at 23 knots, gusting 35
Visibility
1 statute miles
Lowest ceiling
1,300 ft overcast
Temperature
55 °F, dew point 54 °F
Altimeter
29.00 inHg
Observed at
DEN, 9 nm away

Docket · 5

The files NTSB released with the investigation on June 6, 1995, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.5 MB in all.