Douglas DC-9-31 accident at North Canton, Ohio, 27 Nov 1973

Accident narrative

On November 27, 1973, at 2129 e.s.t., an Eastern Air Lines McDonnell-Douglas DC-9-31 ran off the end of runway 01 at Akron-Canton Regional Airport in North Canton, Ohio. After completing an instrument approach and landing, the aircraft traversed 110 feet of unpaved ground and plunged over a 38-foot embankment. The aircraft was substantially damaged, but there was no fire. The 21 passengers and 5 crewmembers sustained various injuries, and there were no fatalities.

### The flight

Eastern Air Lines Flight 300 was a scheduled passenger flight from Miami, Florida, to Akron-Canton via Pittsburgh, Pennsylvania. The crew consisted of Captain William H. Hill, who had 10,881 flight-hours including 736 in the DC-9, and First Officer Andrew R. McTuigg, who had 7,000 flight-hours with 23 in the DC-9. The flight departed Pittsburgh at 2110.

### Sequence of events

At 2118, the flight contacted Akron-Canton approach control. The controller offered a choice between the localizer back course approach to runway 19 or the instrument landing system (ILS) front course approach to runway 01. The weather was reported as an indefinite 200-foot ceiling, sky obscured, 1.5 miles visibility in light rain showers and fog, with a wind of 160 degrees at 8 to 12 knots.

The captain chose the ILS approach to runway 01 to use the electronic glidepath information. The crew noted that the reported ceiling was below the minimum descent altitude for the back course procedure, making it inadvisable, even though landing on runway 01 meant landing downwind on a wet runway. While being vectored, the captain authorized a flight attendant to observe the approach from the cockpit jumpseat.

Before clearing the flight, the controller informed them that a company DC-9 had just taken off and reported water on the runway, but that braking action was "pretty good." A transmission to another aircraft regarding earlier reports of hydroplaning and poor braking was available in Flight 300's cockpit, though the captain stated he did not recall hearing it.

The flight was cleared for the approach at 2125. A reference speed (Vref) of 115 knots indicated airspeed (KIAS) was computed based on an estimated landing weight of 80,000 pounds. Company procedures required a target speed of Vref plus 5 knots on final approach. The tower cleared the flight to land and reported the wind at 160 degrees at 9 knots, yielding an 8-knot tailwind component. The flaps were extended to 50 degrees before the outer marker.

During the approach, the captain noted that the speed command indicator was reading slow. The first officer told the captain they were "a bit fast," noting his airspeed indicator read 130 to 135 KIAS. The captain made remarks about the slow speed command indication and a loading problem, and momentarily added thrust.

The flight data recorder showed the airspeed increased steadily during the final minute of the approach, reaching a maximum of 142 KIAS when the first officer called minimums. Neither crewmember recalled the indicated airspeed just before touchdown.

The aircraft touched down at 139 KIAS. The crew stated it landed on the centerline about 1,000 to 1,500 feet beyond the threshold. The spoilers deployed automatically, and normal reverse thrust and brakes were applied. When the aircraft slowed to between 60 and 70 KIAS, deceleration seemed to stop. The captain increased reverse thrust to maximum continuous thrust and heard engine compressor stalls. The captain stated the brakes felt normal but the aircraft's response did not. At the captain's command, the first officer turned off the antiskid system, and both pilots applied the brakes. The airspeed was less than 60 KIAS when the aircraft left the runway pavement.

### What the investigation found

The aircraft stopped in a field 380 feet beyond the end of the runway. The entire aft fuselage section and empennage separated from the main fuselage. All four main gear tires contained patches of reverted rubber. Of the 16 seriously injured persons, seven sustained vertebral fractures.

The Board's analysis of the flight data recorder indicated the aircraft actually landed about 2,200 to 2,600 feet beyond the runway threshold, leaving 3,800 to 4,200 feet of usable runway in which to stop.

The speed command system components were tested and functioned properly. The Board was unable to determine the reason for the erroneous slow indication. The Board noted that the captain chose to react to the speed command reading by adding thrust without requesting a crosscheck of his instruments with the first officer's.

The investigation determined that the stopping distance required under the existing runway conditions and tailwind, without the use of reverse thrust, was 5,068 feet. Therefore, based on the touchdown point and the 139 KIAS landing speed, it was impossible to stop the aircraft on the runway without reverse thrust.

According to the manufacturer, using 80 percent N1 reverse thrust would have reduced the landing roll to 3,678 feet, which might have allowed the aircraft to stop on the runway. However, the compressor stalls that occurred when the captain applied maximum continuous reverse thrust compromised its effectiveness.

The Board found that viscous and reverted rubber hydroplaning occurred during the latter portion of the landing roll. The deactivation of the antiskid system probably produced a locked wheel skid and the deterioration of braking performance.

The Board concluded that although hydroplaning contributed to the accident, the captain's decision to complete the landing under the existing adverse conditions was the primary factor. The Board also noted that the flight attendant's presence in the cockpit had no effect on the crew's execution of the approach.

### Probable cause

The National Transportation Safety Board determined that the probable cause of the accident was "the captain's decision to complete the landing at an excessive airspeed and at a distance too far down a wet runway to permit the safe stopping of the aircraft." Factors which contributed to the accident were: "(1) Lack of airspeed awareness during the final portion of the approach, (2) an erroneous indication of the speed command indicator, and (3) hydroplaning."