Accident Lockheed L-188A Electra N6101A,

ASN Wikibase Occurrence # 334065

Date:	Tuesday 3 February 1959
Time:	23:56
Type:	Lockheed L-188A Electra
Owner/operator:	American Airlines
Registration:	N6101A
MSN:	1015
Year of manufacture:	1958
Total airframe hrs:	302 hours
Engine model:	Allison 501-D13
Fatalities:	Fatalities: 65 / Occupants: 73
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	1,5 km NE off New York-La Guardia Airport, NY (LGA) - United States of America
Phase:	Approach
Nature:	Passenger - Scheduled
Departure airport:	Chicago-Midway Airport, IL (MDW/KMDW)
Destination airport:	New York-La Guardia Airport, NY (LGA/KLGA)
Investigating agency:	CAB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
American Airlines Flight 320 was a scheduled service from Chicago-Midway Airport, Illinois, USA to New York-La Guardia Airport, New York. The aircraft, a Lockheed L-188A Electra, was off the ground at 21:43 hours and estimated one hour and forty-two minutes en route to New York.
At 23:27, Flight 320 made its first radio contact with La Guardia approach control. Nearing La Guardia Airport, the flight was given vectors for an ILS backcourse approach to runway 22.
Weather was reported to the crew as follows: "four hundred overcast; two miles visibility, light rain and fog".
At 23:53, the flight contacted La Guardia tower, stating they had passed New Rochelle. The flight was subsequently cleared to continue its approach to runway 22. Last radio contact was at 23:55:27 when the flight confirmed clearance to land. The Lockheed Electra aircraft descended until it struck the water seven seconds later, some 5000 feet short of the runway and 600 feet to the right of the extended centreline. Ground speed on impact was 150 mph and undercarriage and flaps were extended. The wreckage sank 10 m deep in the water of the East River.

The investigation board noted that American Airlines requested certification of their L-188A Electra aircraft for flight below 25,000 feet under which limitation it was unnecessary to install flight recorders. This was done in view of the cost of procurement, installation, and maintenance of flight recorders at the time.
The board stated: "a flight recorder in this aircraft would have enabled us to identify the causal factors involved in this accident with far greater precision".

PROBABLE CAUSE: "The Board determines the probable cause of this accident was premature descent below landing minimums which was the result of preoccupation of the crew on particular aspects of the aircraft and its environment to the neglect of essential flight instrument references for attitude and height above the approach surface.
Contributing factors were:
1. Limited experience of the crew with the aircraft type;
2. Faulty approach technique in which the autopilot was used in the heading mode to or almost to the surface;
3. Erroneous setting of the captain's altimeter;
4. Marginal weather in the approach area;
5. Possible misinterpretation of altimeter and rate of descent indicator; and
6. Sensory illusion with respect to height and attitude resulting from visual reference to the few lights existing in the approach area."

Accident investigation: