LAX05TA277

NTSB accident investigation · WSK PZL Mielec M-18A · Elko, NV · August 23, 2005

Accident · Minor injuriesFinal report
Date
August 23, 2005, 14:12 local (21:12 UTC)
Place
Elko, NV
Injuries
1 minor
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N7077NWSK PZL Mielec M-18A
Weather
Visual (VMC) · Day
Status
Completed · report February 26, 2007
Report
Approved by Office Director
Parties
U.S. Department of Interior, Federal Aviation Administration
FAA report
20050823020409A
Case key
62328

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 pilot's failure to adequately plan for the wind direction and speed during a fire retardant delivery flight, which led to a loss of true airspeed, failure to attain a proper climb rate, and the in-flight collision with mountainous terrain. Contributing factors were the high, gusty, tailwind conditions.

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 collision with terrain/waterManeuvering - aerial application
Weather condition - high windFactor
Weather condition - gustsFactor
Weather condition - tailwindFactor
In flight collision with terrain/waterManeuvering - aerial application
In-flight planning/decision - inadequatePilot in commandCause
Airspeed - not maintainedPilot in commandCause
Proper climb rate - not attainedPilot in commandCause

Analysis

The airplane impacted terrain when it encountered tailwind and downdraft conditions during a fire retardant delivery flight over a ridgeline. According to the pilot, he flew the airplane over the drop site between 95 and 100 miles per hour (mph), about 60 feet above the terrain, and with 30 degrees of flaps extended. After dropping the retardant, he applied full power and retracted the flaps to 10 degrees with normal engine indications. The airplane would not climb without losing airspeed and the pilot realized he would not be able to clear the ridgeline in his flight path. He slowed the airplane as much as possible before the airplane collided with terrain. The weather observation at a nearby airport and reports from ground personnel close to the site indicated high and gusty wind conditions with velocities as high as 40 knots existed at the time of the accident, and would have resulted in a tailwind condition for the airplane as it made the retardant drop.

Factual narrative

On August 23, 2005, at 1412 Pacific daylight time, a WSK PZL Mielec M-18A airplane, N7077N (call sign Tanker 426), impacted terrain while maneuvering through a fire retardant drop 12 miles north of Elko, Nevada. The Bureau of Land Management (BLM) was operating the aircraft as a public-use firefighting tool under the provisions of 14 CFR Part 91. The commercial pilot, who was the sole occupant, sustained minor injuries. The airplane was substantially damaged. Visual meteorological conditions prevailed and a company flight plan was filed. The local flight departed the Elko Regional Airport at 1403, and was dropping retardant on the Sherman Fire when the accident occurred.

According to the BLM personnel, the pilot reported dropping a fire retardant load (approximately 500 gallons or 4,035 pounds) downhill in a downwind condition. He dropped the fire retardant at an indicated airspeed between 95 and 100 miles per hour (mph), about 60 feet above the ground, with 30 degrees of flaps extended. After dropping the load, the pilot applied full power, raised flaps to 10 degrees (incrementally), and attempted to climb. According to the pilot, the airplane was incapable of climbing without losing airspeed; however, the engine was producing full power and there were no noted anomalies with the airplane or engine. When the pilot realized he would be unable to clear the ridgeline in front of him, he maintained a wings level attitude and slowed the airplane as much as possible before colliding with terrain.

The airplane impacted the ground at the 7,044-foot level of the 7,090-foot ridge, resulting in the separation of the landing gear, and substantial damage to the wings and flight control surfaces. The pilot was picked up by a ground vehicle and transported to a hospital with minor injuries.

According to the pilot's written statement, the flight was uneventful until reaching the ridgeline near the fire. When the airplane crossed the top of the ridgeline it "encountered turbulence and a down draft." The pilot completed the drop and added power to full throttle and retracted flaps to 10 degrees with an airspeed of 110 mph. The pilot reported that all engine indications were normal and there were no anomalies noted with either the airplane or engine.

The pilot continued to raise the nose to arrest the descent rate and slowed the airplane to 95 mph, but the airplane continued to lose altitude. He then realized the airplane would be unable to clear the next ridgeline and elected to maintain full power while pitching up and slowing the airspeed as much as possible. When the airplane was 20 feet above the ground, the pilot maintained a nose high pitch attitude until the airplane stalled and contacted the ground with little forward speed. He secured the airplane and exited the aircraft.

The pilot reported the wind from the west-southwest at 20 knots with gusts to 40 knots at the time of the accident. At 1456, the Elko Regional Airport's weather observation facility (field elevation of 5,140 feet mean sea level) reported the wind from 260 degrees at 19 knots with gusts to 25 knots. BLM personnel indicated that ground units near the accident site were reporting winds up to 30 knots.

The pilot reported accumulating a total of 13,460 flight hours, of which 550 hours were accrued in the same make and model as the accident airplane.

When asked what could be done to prevent a similar accident from occurring, the pilot suggested the following:

1) Once it is determined that gusty wind conditions exist, tanker pilots should conduct at least one dry pass at a minimum of 100 feet above the ground before making retardant delivery pass.

2) If a lead airplane experiences turbulence or gusty wind conditions they should report the information to dispatch as soon as possible for dissemination to the other air crews.

3) Downwind retardant deliveries over a ridgeline should be avoided in all cases when winds are reported to be over 25 mph.

4) Pilots should never rely on power alone to get out of a downdraft situation.

Aircraft

Registration
N7077N
Reported as
WSK PZL Mielec M-18A
Category
Airplane
Serial number
1Z023-03
Airframe hours
4,410.1
Engine
Lycoming T-53L7A, 1,100 horsepower, turbo prop
Damage
Substantial damage
Flight
Public aircraft - federal · Public use
Operator
Bureau of Land Management
Registered owner
Airwork Enterprises of Florida, Inc.
Airworthiness certificate
Special, Restricted (Special)
Last inspection
Annual · May 1, 2005 · 56.5 hours before
Departed
EKO · Elko, NV
Destination
EKO · Elko, NV
Flight plan
Company VFR

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
67
Injuries
Minor
Certificate
Commercial
Airplane ratings
Single-engine sea, Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 2, With waivers/limitations
Last flight review
December 1, 2004
Seat
Center
Flight hours
13,460 total · 550 in this make and model · 12,460 as pilot in command · 55 in the last 90 days · 22 in the last 30 days · 6 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
260° at 19 knots, gusting 25
Visibility
10 statute miles
Lowest ceiling
None
Temperature
91 °F, dew point 45 °F
Altimeter
30.04 inHg
Observed at
EKO, 12 nm away

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.

Other investigations on N7077N · 1

Matched to the same aircraft by N-number and date.