Accident Convair CV-580 N5832,

ASN Wikibase Occurrence # 330793

Date:	Monday 7 June 1971
Time:	09:49
Type:	Convair CV-580
Owner/operator:	Allegheny Airlines
Registration:	N5832
MSN:	384
Year of manufacture:	1956
Total airframe hrs:	33058 hours
Engine model:	Allison 501-D13
Fatalities:	Fatalities: 28 / Occupants: 31
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	1,5 km S of New Haven Airport, CT (HVN) - United States of America
Phase:	Approach
Nature:	Passenger - Scheduled
Departure airport:	Groton-New London Airport, CT (GON/KGON)
Destination airport:	New Haven-Tweed Airport, CT (HVN/KHVN)
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Allegheny Airlines Flight 485, a Convair CV-580, departed Washington, DC, at 07:14 hours local time on a domestic passenger service to Philadelphia (Pennsylvania) via Groton and New Haven (Connecticut).
Visibility at Groton was poor, with an indefinite ceiling of 200 feet and a visibility in fog of around 3/4 to 1 mile. After three missed instrument approaches, a fourth attempt was made using a contact approach procedure, which resulted in the aircraft landing at 09:22.
Twenty passengers deplaned at Groton, Fourteen passengers were boarded and 713 pounds of cargo were loaded at Groton. The flight departed then at 09:35 for New Haven.
At 09:48, the New Haven Tower controller advised the flight of winds from 190 degrees at 5 knots and offered runway 02 or 20 for landing. Despite a company directive prohibiting a downwind landing at
the New Haven Airport, the flight crew requested an approach and landing on runway 02.
The approach was flown over sea in poor visibility conditions. At the minimum descent altitude of 380 feet no ground features were observed by the crew. Nevertheless, the captain continued the approach. When the copilot observed the water below, he stated to the captain that "we're not twenty feet off the water."
Immediately thereafter the airplane struck three beach cottages located on the northern shore of Long Island Sound, at a height approximately 25 feet above mean sea level, 4890 feet from the displaced threshold of runway 2 and approximately 510 feet to the right of the extended centerline of the runway.
An intense fire ensued immediately upon initial impact and continued to burn to the point of near total destruction of the upper portion of the fuselage and cabin area of the airplane.

The Convair was originally manufactured as a Convair CV-440 and converted to a Convair 580. The plane had flown 8406 hours since the conversion in September 1967.

PROBABLE CAUSE: "The captain's intentional descent below the prescribed minimum descent altitude under adverse weather conditions without adequate forward visibility or the crew's sighting of the runway environment. The captain disregarded advisories from his first officer that minimum descent altitude had been reached and that the airplane was continuing to descend at a normal descent rate and airspeed. The Board was unable to determine what motivated the captain to disregard prescribed operating procedures and altitude restrictions and finds it difficult to reconcile the actions he exhibited during the conduct of this flight."

Accident investigation: