Mohawk Airlines Flight 411
Encyclopedia
Mohawk Airlines
Flight 411, a Fairchild FH-227B
twin-engine turboprop
, registered N7811M, was a scheduled domestic passenger service operated by Mohawk Airlines
, between Albany
and Glens Falls
, New York. On November 19, 1969, it crashed into Pilot Knob Mountain, killing all 14 passengers and crew on board.
The National Transportation Safety Board (NTSB) concluded that the crash was caused by the captain's improper execution of an instrument approach
, combined with a severe downdraft at a low altitude, which resulted in the aircraft descending uncontrollably into terrain.
turboprop
, departed from Albany International Airport
near Albany, New York
. It was operating as a scheduled passenger/cargo flight on an instrument flight rules (IFR) flight plan to its destination of Warren County Airport
in Glens Falls, New York
, 37 nautical miles (69 km) northeast, with an estimated flight time of about 15 minutes.
At 20:07:32 EST, just 4 minutes after takeoff
, Flight 411 was cleared by air traffic control
(ATC) for "a VOR
approach to runway
19". The aircraft overflew the Glens Falls airport and proceeded northbound, subsequently reversing course. Shortly after course reversal, at about 20:20 EST, the aircraft hit trees on the northwest slope of the Pilot Knob Mountain, then impacted a rock cliff from which it fell 34 feet (10 m) and became lodged between trees and caught fire. Of the 11 passengers and 3 crew on board, there were no survivors.
The accident was investigated by the National Transportation Safety Board (NTSB). The Flight Data Recorder
was recovered intact from the wreckage, but the Cockpit Voice Recorder
had been damaged in the post-crash fire and was unusable.
The weather at Glens Falls at the time of the accident was reported as "2,100 (feet) overcast, visibility 7 (miles) in light rain, wind 180 (degrees) at 12 (knots), peak gusts 22 (knots), altimeter 2980, runway 19 in use". The surface temperature was 54 degrees Fahrenheit (12 degrees Celsius).
The investigation revealed that ATC cleared the flight to "the VOR
approach
", without actually specifying which specific VOR approach procedure was to be used, possibly leaving it to the flight crew's discretion. According to the radio communication transcript, the flight crew did not inquire as to which specific approach was in effect. There were two published VOR approaches at the time, one from the north and one from the south. The northern approach, called "VOR/DME 19", was not legally available to the crew under these circumstances, as Mohawk company policy prohibited reliance on DME
as a primary navigational instrument. The other VOR approach, called "VOR 1", was the only one legally available to the flight, and would have required descending while approaching the airport from the south during the final approach segment, followed by a "circle to land" maneuver, landing to the south on runway 19.
Despite this, possibly due to their concerns with passenger comfort (the VOR 1 approach would have required performing the "circle to land" maneuver at a relatively low altitude over the airport to land on runway 19), or possibly by simply being late to set up for the recommended VOR 1 approach (the flight time was only about 8 minutes from takeoff at Albany to the Glens Falls area, with a significant tailwind
component of approximately 50 knots), the crew did not execute the VOR 1 approach. Instead, the crew appeared to select an improvised and unauthorized modified version of the VOR/DME 19 approach, which included flying outbound followed by a course reversal at about 10 nautical miles (18.5 km) north of the airport, over Lake George
. As the crew performed what appeared to be an unpublished and unauthorized procedure turn for course reversal on the VOR/DME 19 approach path, they descended prematurely and hit the side of a mountain. It was subsequently determined that a 60 knots (117.6 km/h) southerly wind created a downdraft effect which, coupled with the aircraft's low altitude over the terrain, contributed to the crash.
In their final report, issued on June 25, 1970, the NTSB determined the following official Probable Cause for the accident:
Mohawk Airlines
Mohawk Airlines was an airline that operated in the Mid-Atlantic region of the United States, primarily the states of New York and Pennsylvania from the mid-1940s until its acquisition by Allegheny Airlines in 1972...
Flight 411, a Fairchild FH-227B
Fairchild Hiller FH-227
The Fairchild F-27 and Fairchild Hiller FH-227 were versions of the Fokker F27 Friendship twin-engined turboprop passenger aircraft manufactured under license by Fairchild Hiller in the United States...
twin-engine turboprop
Turboprop
A turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear.The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller...
, registered N7811M, was a scheduled domestic passenger service operated by Mohawk Airlines
Mohawk Airlines
Mohawk Airlines was an airline that operated in the Mid-Atlantic region of the United States, primarily the states of New York and Pennsylvania from the mid-1940s until its acquisition by Allegheny Airlines in 1972...
, between Albany
Albany, New York
Albany is the capital city of the U.S. state of New York, the seat of Albany County, and the central city of New York's Capital District. Roughly north of New York City, Albany sits on the west bank of the Hudson River, about south of its confluence with the Mohawk River...
and Glens Falls
Glens Falls, New York
Glens Falls is a city in Warren County, New York, United States. Glens Falls Metropolitan Statistical Area. The population was 14,700 at the 2010 census...
, New York. On November 19, 1969, it crashed into Pilot Knob Mountain, killing all 14 passengers and crew on board.
The National Transportation Safety Board (NTSB) concluded that the crash was caused by the captain's improper execution of an instrument approach
Instrument approach
For aircraft operating under instrument flight rules , an instrument approach or instrument approach procedure is a series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing, or to a point...
, combined with a severe downdraft at a low altitude, which resulted in the aircraft descending uncontrollably into terrain.
History of flight
On the evening of November 19, 1969, at about 20:03 EST, Mohawk Airlines Flight 411, a twin engine Fairchild FH-227BFairchild Hiller FH-227
The Fairchild F-27 and Fairchild Hiller FH-227 were versions of the Fokker F27 Friendship twin-engined turboprop passenger aircraft manufactured under license by Fairchild Hiller in the United States...
turboprop
Turboprop
A turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear.The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller...
, departed from Albany International Airport
Albany International Airport
Albany International Airport is a public use airport located six nautical miles northwest of the central business district of Albany, in Albany County, New York, United States. It is owned by the Albany County Airport Authority....
near Albany, New York
Albany, New York
Albany is the capital city of the U.S. state of New York, the seat of Albany County, and the central city of New York's Capital District. Roughly north of New York City, Albany sits on the west bank of the Hudson River, about south of its confluence with the Mohawk River...
. It was operating as a scheduled passenger/cargo flight on an instrument flight rules (IFR) flight plan to its destination of Warren County Airport
Floyd Bennett Memorial Airport
Floyd Bennett Memorial Airport , formerly known as Warren County Airport, is a public airport located in the town of Queensbury three miles northeast of the city of Glens Falls in Warren County, New York, USA...
in Glens Falls, New York
Glens Falls, New York
Glens Falls is a city in Warren County, New York, United States. Glens Falls Metropolitan Statistical Area. The population was 14,700 at the 2010 census...
, 37 nautical miles (69 km) northeast, with an estimated flight time of about 15 minutes.
At 20:07:32 EST, just 4 minutes after takeoff
Takeoff
Takeoff is the phase of flight in which an aerospace vehicle goes from the ground to flying in the air.For horizontal takeoff aircraft this usually involves starting with a transition from moving along the ground on a runway. For balloons, helicopters and some specialized fixed-wing aircraft , no...
, Flight 411 was cleared by air traffic control
Air traffic control
Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...
(ATC) for "a VOR
VHF omnidirectional range
VOR, short for VHF omnidirectional radio range, is a type of radio navigation system for aircraft. A VOR ground station broadcasts a VHF radio composite signal including the station's identifier, voice , and navigation signal. The identifier is typically a two- or three-letter string in Morse code...
approach to runway
Runway
According to ICAO a runway is a "defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft." Runways may be a man-made surface or a natural surface .- Orientation and dimensions :Runways are named by a number between 01 and 36, which is generally one tenth...
19". The aircraft overflew the Glens Falls airport and proceeded northbound, subsequently reversing course. Shortly after course reversal, at about 20:20 EST, the aircraft hit trees on the northwest slope of the Pilot Knob Mountain, then impacted a rock cliff from which it fell 34 feet (10 m) and became lodged between trees and caught fire. Of the 11 passengers and 3 crew on board, there were no survivors.
Investigation and final report
Flight data recorder
A flight data recorder is an electronic device employed to record any instructions sent to any electronic systems on an aircraft. It is a device used to record specific aircraft performance parameters...
was recovered intact from the wreckage, but the Cockpit Voice Recorder
Cockpit voice recorder
A cockpit voice recorder , often referred to as a "black box", is a flight recorder used to record the audio environment in the flight deck of an aircraft for the purpose of investigation of accidents and incidents...
had been damaged in the post-crash fire and was unusable.
The weather at Glens Falls at the time of the accident was reported as "2,100 (feet) overcast, visibility 7 (miles) in light rain, wind 180 (degrees) at 12 (knots), peak gusts 22 (knots), altimeter 2980, runway 19 in use". The surface temperature was 54 degrees Fahrenheit (12 degrees Celsius).
The investigation revealed that ATC cleared the flight to "the VOR
VHF omnidirectional range
VOR, short for VHF omnidirectional radio range, is a type of radio navigation system for aircraft. A VOR ground station broadcasts a VHF radio composite signal including the station's identifier, voice , and navigation signal. The identifier is typically a two- or three-letter string in Morse code...
approach
Instrument approach
For aircraft operating under instrument flight rules , an instrument approach or instrument approach procedure is a series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing, or to a point...
", without actually specifying which specific VOR approach procedure was to be used, possibly leaving it to the flight crew's discretion. According to the radio communication transcript, the flight crew did not inquire as to which specific approach was in effect. There were two published VOR approaches at the time, one from the north and one from the south. The northern approach, called "VOR/DME 19", was not legally available to the crew under these circumstances, as Mohawk company policy prohibited reliance on DME
Distance Measuring Equipment
Distance measuring equipment is a transponder-based radio navigation technology that measures distance by timing the propagation delay of VHF or UHF radio signals....
as a primary navigational instrument. The other VOR approach, called "VOR 1", was the only one legally available to the flight, and would have required descending while approaching the airport from the south during the final approach segment, followed by a "circle to land" maneuver, landing to the south on runway 19.
Despite this, possibly due to their concerns with passenger comfort (the VOR 1 approach would have required performing the "circle to land" maneuver at a relatively low altitude over the airport to land on runway 19), or possibly by simply being late to set up for the recommended VOR 1 approach (the flight time was only about 8 minutes from takeoff at Albany to the Glens Falls area, with a significant tailwind
Tailwind
A tailwind is a wind that blows in the direction of travel of an object, while a headwind blows against the direction of travel. A tailwind increases the object's speed and reduces the time required to reach its destination, while a headwind has the opposite effect...
component of approximately 50 knots), the crew did not execute the VOR 1 approach. Instead, the crew appeared to select an improvised and unauthorized modified version of the VOR/DME 19 approach, which included flying outbound followed by a course reversal at about 10 nautical miles (18.5 km) north of the airport, over Lake George
Lake George (New York)
Lake George, nicknamed the Queen of American Lakes, is a long, narrow oligotrophic lake draining northwards into Lake Champlain and the St. Lawrence River Drainage basin located at the southeast base of the Adirondack Mountains in northern New York, U.S.A.. It lies within the upper region of the...
. As the crew performed what appeared to be an unpublished and unauthorized procedure turn for course reversal on the VOR/DME 19 approach path, they descended prematurely and hit the side of a mountain. It was subsequently determined that a 60 knots (117.6 km/h) southerly wind created a downdraft effect which, coupled with the aircraft's low altitude over the terrain, contributed to the crash.
In their final report, issued on June 25, 1970, the NTSB determined the following official Probable Cause for the accident:
See also
- List of notable accidents and incidents on commercial aircraft
- Mohawk Airlines Flight 405Mohawk Airlines Flight 405Mohawk Airlines Flight 405, a Fairchild Hiller FH-227 twin-engine turboprop airliner registered N7818M, was a domestic scheduled passenger flight operated by Mohawk Airlines that crashed into a house on March 3, 1972, on final approach to Albany County Airport , New York, killing 17 people.-Flight...
External links
- Airliners.net Photo of accident aircraft N7811M, a year before the accident, July 20, 1968
- Glens Falls Airport on AirNav Database