Dillingham Airport
Aircraft Accident/Incident Report

Aleknagik, Alaska 99555
Friday, March 8, 2013 8:15 AST

NTSB Narrative Summary Released at Completion of Accident

The airplane was operating in instrument meteorological conditions and, as it approached the destination airport, the pilot requested the RNAV/GPS runway 19 approach and asked for routing directly to ZEDAG, the initial approach fix (IAF). At the time of the pilot's request, the airplane was about 30 miles southeast of the IAF at an altitude of about 5,900 feet mean sea level (msl). The air traffic controller cleared the airplane to fly directly to the IAF followed by the ZEDAG transition and the RNAV/GPS runway 19 approach, stating, "maintain at or above 2,000" feet until established on a published segment of the approach. The flight crewmembers repeated the clearance back to the controller as "maintain 2,000" feet until established, and they began descending the airplane toward the IAF. About 6 minutes later, the pilot requested to enter the holding pattern while they checked on runway conditions on another radio frequency, and the controller cleared them to hold "as published." At the time of the pilot's request, the airplane was at an altitude of about 2,200 feet msl. As depicted on the published instrument approach procedure, the terminal arrival area (TAA) minimum altitude when approaching the IAF from the southeast (the direction from which the accident flight approached) is 5,400 feet msl, and the published holding pattern at the IAF is 4,300 feet msl due to rising terrain in the area.Therefore, the flight crewmember's acceptance of what they believed to be a clearance to 2,000 feet, their descent to that altitude, and their initiation of a hold at that altitude indicates a lack of awareness of the information contained on the published procedure. Such a lack of awareness is inconsistent with pilot-in-command responsibilities and company procedures that require an instrument approach briefing during the descent and approach phases of flight. If the flight crewmembers had reviewed the published approach procedure and briefed it per the company's descent and approach checklist, they should have noticed that the minimum safe altitude in the TAA southeast of the IAF was 5,400 feet msl and that the minimum altitude for the hold was 4,300 feet msl. Examination of the wreckage and debris path evidence is consistent with the airplane having collided with rising terrain at 2,000 feet msl while flying in a wings-level attitude on the outbound leg of the holding pattern, which the flight crew should have flown at 4,300 feet msl. However, the air traffic controller did not adhere to guidance contained in Federal Aviation Administration Order 7110.65, and his approach clearance to "maintain at or above 2,000 feet" msl until established on a published segment of the approach was ambiguous. The controller's approach clearance should have instructed the pilot to "proceed direct to ZEDAG, enter the TAA at or above 5,400 feet, cleared RNAV runway 19 approach." Instead, he instructed the pilot without specifying the segment of the approach that should be flown at 2,000 feet. Further, the controller did not notice the pilot's incorrect readback of the clearance in which he indicated that he intended to "maintain 2,000 feet" until established on the approach. Further, he did not appropriately monitor the flight's progress and intervene when the airplane descended to 2,000 feet msl. As a result, the airplane was permitted to descend below the minimum instrument altitudes applicable to the route of flight and enter the holding pattern well below the published minimum holding altitude. Air traffic control (ATC) recorded automation data showed that the airplane's trajectory generated aural and visual minimum safe altitude warnings on the controller's radar display. However, the controller did not issue any terrain warnings or climb instructions to the flight crew. The controller said that he was not consciously aware of any such warnings from his display. These automated warnings should have been sufficient to prompt the controller to evaluate the airplane's position and altitude, provide a safety alert to the pilot in a timely manner, and instruct the pilot to climb to a safe altitude; it could not be determined why the controller was unaware of the warnings. The airplane was equipped with three pieces of navigation equipment that should have provided visual and aural terrain warnings to the flight crewmembers if they had not inhibited the function and if the units were operating properly. Damage precluded testing the equipment or determining the preaccident configuration of the units; however, the flight crew reported no equipment anomalies predeparture.

NTSB Probable Cause Narrative

The flight crew's failure to maintain terrain clearance, which resulted in controlled flight into terrain in instrument meteorological conditions. Contributing to the accident were the flight crew's failure to correctly read back and interpret clearance altitudes issued by the air traffic controller, their failure to adhere to minimum altitudes depicted on the published instrument approach chart, and their failure to adhere to company checklists. Also contributing to the accident were the air traffic controller's issuance of an ambiguous clearance to the flight crew, which resulted in the airplane's premature descent, his failure to address the pilot's incorrect read back of the assigned clearance altitudes, and his failure to monitor the flight and address the altitude violations and issue terrain-based safety alerts.

Event Information

Type of Event Accident
Event Date 3/8/2013
Event Day of the Week Friday
Time of Event 815
Event Time Zone Atlantic Standard Time
Event City Aleknagik
Event State ALASKA
Event Country --
Zipcode of the event site 99555
Event Date Year 2013
Event Date Month 3
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 591904N
Event Location Longitude 1582104W
Event Location Airport Dillingham Airport
Event Location Nearest Airport ID PADL
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles 20
Degrees magnetic from airport 15
Airport Elevation 82
Weather Briefing Completeness --
Investigator's weather source Weather Observation Facility
Time of the weather observation 745 Atlantic Standard Time
Direction of event from weather observation facility (degrees) 180
Weather Observation Facility ID PADL
Elevation of weather observation facility 85
Distance of event from weather observation facility (units?) 20
Time Zone of the weather observation AST
Lighting Conditions Day
Lowest Ceiling Height 1500
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions --
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 7
Air Temperature at event time (in degrees celsius) 1
Dew Point at event time (in degress fahrenheit) 1
Wind Direction (degrees magnetic) 100
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 17
Wind Velocity Indicator --
Wind Gust Indicator Gusting
Wind Gust (knots) 30
Altimeter Setting at event time (in. Hg) 29.09
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Fatal
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal 2
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 32935
NTSB Notification Source FAA Anchorage, ROC
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Jul 23 2014 1:12PM
User who most recently changed record stam
Basic weather conditions Instrument Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N116AX
NTSB Number ANC13FA030
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed IFR
Flight plan Was Activated? Yes
Damage Destroyed
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BEECH
Aircraft Model 1900C
Aircraft Series Identifier --
Aircraft Serial Number UC17
Certified Max Gross Weight 17600
Aircraft Category Airplane
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 19
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Mar 7 2013 12:00AM
Airframe hours since last inspection 188
Airframe Hours 29824
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site Yes
ELT Type C126
Aircraft Owner Name ALASKA CENTRAL EXPRESS INC
Aircraft Owner Street Address --
Aircraft Owner City ANCHORAGE
Aircraft Owner State AK
Aircraft Owner Country USA
Aircraft Owner Zipcode 99502-1094
Operator is an individual? No
Operator Name ALASKA CENTRAL EXPRESS INC
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City ANCHORAGE
Operator State AK
Operator Country USA
Operator Zip code 99502-1094
Operator Code YADA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation --
Operator Certificate Number YADA179J
Indicates whether an air carrier operation was scheduled or not Non-scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Cargo
Type of Flying (Per_Bus / Primary) --
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code PAKN
Departure City King Salmon
Departure State AK
Departure Country USA
Departure Time 750
Departure Time Zone AST
Destination Same as Local Flt --
Destination Airport Code PADL
Destination City Dillingham
Destination State AK
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Aug 6 2014 11:55AM
User who most recently changed record stam
Since inspection or accident Last Inspection
Event Location Runway Number and Location 19
Runway Length 6400
Runway Width 150
Sight Seeing flight No
Air Medical Flight No
Medical Flight --