ANC02LA053

NTSB accident investigation · de Havilland DHC-6-300 · Ketchikan, AK · June 20, 2002

Accident · No injuriesLimited investigationFinal report
Date
June 19, 2002, 17:00 local (Jun 20, 2002, 01:00 UTC)
Place
Ketchikan, AK
Injuries
31 uninjured
Phase of flight
Taxi
Aircraft
N353PMde Havilland DHC-6-300N235SAde Havilland DHC-6-300
Weather
Visual (VMC) · Day
Status
Completed · report January 16, 2003
Report
Approved by Office Director
NTSB office
Alaska Regional Office
Parties
Federal Aviation Administration
Case key
54996

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

On this page

Probable cause

The failure of a ground handler to follow company proceedure/directives, and his premature release of a mooring line. Factors associated with the accident were the congested operations area, and the operator's failure to provide adequate safe zones for the airplanes.

The failure of a ground handler to follow company procedures/directives, and his premature release of a mooring line. Factors associated with the accident were the congested operations area, and the operator's failure to provide adequate safe zones for the airplanes.

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.

Collision between aircraft (other than midair)Taxi
Procedures/directives - not followedGround personnelCause
Facility inadequateCompany/operator managementFactor
Airport/facilities - congestedFactor
Tie down - removedGround personnelCause
Collision between aircraft (other than midair)Standing - engine(s) not operating
Procedures/directives - not followedGround personnelCause
Airport/facilities - congestedFactor
Tie down - removedGround personnelCause
Facility inadequateCompany/operator managementFactor

Analysis

A float-equipped deHavilland DHC-6, N235SA, was moored at a dock. The passengers were boarded, and the two pilots were finishing preflight duties. The airplane's engines were not running. Moored at the same dock, about four feet behind N235SA, was another float-equipped deHavilland DHC-6, N353PM. Both airplanes were being operated as sightseeing flights. The pilots of N353PM had completed their pretaxi checks, and the engines were running. The pilot in command of N353PM signaled the dockhand to disconnect the shore power. The dockhand disconnected the shore power, and without direction to do so, let go the mooring ropes. N353PM, under idle power, surged forward into the tail of N235SA. Both airplanes received substantial damage. Company procedures at the time of the accident directed the dockhand to wait for a signal from the pilot before letting go the mooring ropes. Post-accident the operation has been moved to a longer dock, to provide greater distance between airplanes. The procedure has been changed, and the first officer is now responsible for releasing the mooring ropes at the direction of the pilot.

A float-equipped deHavilland DHC-6, N235SA, was moored at a dock. The passengers were boarded, and the two pilots were finishing preflight duties. The airplane's engines were not running. Moored at the same dock, about four feet behind N235SA, was another float-equipped deHavilland DHC-6, N353PM. Both airplanes were being operated as sightseeing flights. The pilots of N353PM had completed their pretaxi checks, and the engines were running. The pilot in command of N353PM signaled the dockhand to disconnect the shore power. The dockhand disconnected the shore power, and without direction to do so, let go the mooring ropes. N353PM, under idle power, surged forward into the tail of N235SA. Both airplanes received substantial damage. Company procedures at the time of the accident directed the dockhand to wait for a signal from the pilot before letting go the mooring ropes. Post-accident the operation has been moved to a longer dock, to provide greater distance between airplanes. The procedure has been changed, and the first officer is now responsible for releasing the mooring ropes at the direction of the pilot.

Factual narrative

On June 19, 2002, about 1700 Alaska daylight time, a float-equipped deHavilland DHC-6-300 airplane, N353PM, sustained substantial damage while water taxiing at Ketchikan, Alaska, when it struck another float-equipped deHavilland DHC-6-300, N235SA, which also sustained substantial damage. N235SA was moored to the dock when the accident occurred. Both airplanes were being operated as visual flight rules (VFR) local area sightseeing flights under Title 14, CFR Part 135, by PROMECH INC., dba, Seaborne Seaplane Adventures, of Ketchikan. The captain, the first officer, and the 15 passengers on N353PM, were not injured. The captain, the first officer, and the 12 passengers on N235SA, were not injured. Visual meteorological conditions prevailed, and VFR company flight following procedures were in effect.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on June 20, 2002, the captain of N353PM said he was preparing the airplane for departure when the accident occurred. The airplane doors were closed, passengers seated, and engines running at idle power. The airplane was still tied to the dock, and the shore power cable was attached. The captain said he gave the appropriate hand signal to the dockhand to disconnect the shore power cable. He said after disconnecting the shore power cable, the dockhand released the mooring rope holding the airplane to the dock. The captain said an additional hand signal is used to signal the dockhand to release the mooring line, and that signal was not given. The airplane, N353PM, surged forward under idle power, and its nose collided with the tail of N235SA, which was moored to the dock about four feet in front of N353PM.

The captain of N353PM said he was able to shut down the engines before the two airplanes made contact, but the propellers were still wind-milling during the collision. N353PM sustained substantial damage to its propeller blades and nose. N235SA sustained substantial damage to its elevators and vertical stabilizer.

During a conversation with the IIC, the director of operations for the operator said the captain and first officer of N235SA had just finished loading passengers, and were standing on the dock at the time of the accident. N235SA was moored to the dock, and the engines were not running. He said after the accident, the floatplane operation has been moved to another dock where the airplanes are separated by at least 50 feet. He said the operations manual/procedures have been revised, and dockhands no longer handle departing airplanes. Under the new procedure the captain (PIC) is at the airplane's controls, and the first officer releases the mooring lines.

On June 19, 2002, about 1700 Alaska daylight time, a float-equipped deHavilland DHC-6-300 airplane, N353PM, sustained substantial damage while water taxiing at Ketchikan, Alaska, when it struck another float-equipped deHavilland DHC-6-300, N235SA, which also sustained substantial damage. N235SA was moored to the dock when the accident occurred. Both airplanes were being operated as visual flight rules (VFR) local area sightseeing flights under Title 14, CFR Part 135, by PROMECH INC., dba, Seaborne Seaplane Adventures, of Ketchikan. The captain, the first officer, and the 15 passengers on N353PM, were not injured. The captain, the first officer, and the 12 passengers on N235SA, were not injured. Visual meteorological conditions prevailed, and VFR company flight following procedures were in effect.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on June 20, 2002, the captain of N353PM said he was preparing the airplane for departure when the accident occurred. The airplane doors were closed, passengers seated, and engines running at idle power. The airplane was still tied to the dock, and the shore power cable was attached. The captain said he gave the appropriate hand signal to the dockhand to disconnect the shore power cable. He said after disconnecting the shore power cable, the dockhand released the mooring rope holding the airplane to the dock. The captain said an additional hand signal is used to signal the dockhand to release the mooring line, and that signal was not given. The airplane, N353PM, surged forward under idle power, and its nose collided with the tail of N235SA, which was moored to the dock about four feet in front of N353PM.

The captain of N353PM said he was able to shut down the engines before the two airplanes made contact, but the propellers were still wind-milling during the collision. N353PM sustained substantial damage to its propeller blades and nose. N235SA sustained substantial damage to its elevators and vertical stabilizer.

During a conversation with the IIC, the director of operations for the operator said the captain and first officer of N235SA had just finished loading passengers, and were standing on the dock at the time of the accident. N235SA was moored to the dock, and the engines were not running. He said, after the accident, the floatplane operation has been moved to another dock where the airplanes are separated by at least 50 feet. He said the operations manual/procedures have been revised, and dockhands no longer handle departing airplanes. Under the new procedure, the captain (PIC) is at the airplane's controls, and the first officer releases the mooring lines.

Aircraft · 2

Registration
N353PM
Reported as
de Havilland DHC-6-300
Category
Airplane
Serial number
351
Airframe hours
13,701.1
Engine
Pratt & Whitney PT6A-27, 680 horsepower, turbo prop
Damage
Substantial damage
Flight
Part 135
Operator
Promech Inc., doing business as Seaborne Seaplane Adventures
Registered owner
N353pm, LLC
Airworthiness certificate
Standard, Normal
Last inspection
Continuous airworthiness · September 11, 2001 · 95.6 hours before
Departed
Ketchikan, AK
Destination
Ketchikan, AK
Flight plan
Company VFR
Airport
WFB · Ketchikan Water Front

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.

Registration
N235SA
Reported as
de Havilland DHC-6-300
Category
Airplane
Serial number
771
Airframe hours
25,732
Engine
Pratt & Whitney PT-6A-27, 680 horsepower, turbo prop
Damage
Substantial damage
Flight
Part 135
Operator
Promech Inc., doing business as Seaborne Seaplane Adventures
Registered owner
Kevin M. Hack
Airworthiness certificate
Standard, Normal
Last inspection
Continuous airworthiness · May 23, 2002 · 106 hours before
Flight plan
Company VFR
Airport
WFB · Ketchikan Water Front

Flight crew · 4

As NTSB recorded them. NTSB leaves out names.

Role
Pilot, aircraft N353PM
Age
36
Injuries
None
Certificates
Commercial, Airline transport
Airplane ratings
Single-engine sea, Multi-engine land, Single-engine land, Multi-engine sea
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--w/ waivers/lim
Last flight review
May 16, 2002
Seat
Left
Flight hours
11,523 total · 1,042 in this make and model · 11,323 as pilot in command · 95 in the last 90 days · 3 in the last 30 days
Role
Co-pilot, aircraft N353PM
Injuries
None
Medical
Class 2, Valid Medical--no waivers/lim.
Role
Pilot, aircraft N235SA
Age
39
Injuries
None
Certificate
Airline transport
Airplane ratings
Multi-engine sea, Single-engine sea, Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--w/ waivers/lim
Last flight review
February 19, 2002
Seat
Left
Flight hours
12,900 total · 880 in this make and model · 12,586 as pilot in command · 250 in the last 90 days · 170 in the last 30 days · 7 in the last 24 hours
Role
Co-pilot, aircraft N235SA
Age
32
Injuries
None
Certificate
Commercial
Airplane ratings
Multi-engine land, Multi-engine sea, Single-engine sea, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--w/ waivers/lim
Last flight review
May 11, 2002
Seat
Right
Flight hours
7,300 total · 230 in this make and model · 6,800 as pilot in command · 246 in the last 90 days · 70 in the last 30 days · 6 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
120° at 7 knots
Visibility
10 statute miles
Lowest ceiling
4,400 ft overcast
Temperature
55 °F, dew point 46 °F
Altimeter
30.19 inHg
Observed at
PAKT, 1 nm away

Docket · 2

The files NTSB released with the investigation on November 11, 2002, on NTSB’s docket system: statements, records, photos and specialists’ reports. 978 KB in all.

FAA reports on this event · 2

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