Douglas DC-9 accident at St. Croix, Virgin Islands, 2 May 1970

Accident narrative

On May 2, 1970, an Overseas National Airways (ONA) Douglas DC-9 operating as Antilliaanse Luchtvaart Maatschappij (ALM) Flight 980 ditched in the Caribbean Sea approximately 30 miles east-northeast of St. Croix, Virgin Islands. Of those aboard, 40 survived, including 35 passengers and five crewmembers. Twenty-three people, including two infants and a stewardess, did not survive. The aircraft sank in water more than 5,000 feet deep and was not recovered.

### The flight

The flight operated under a lease agreement from John F. Kennedy International Airport in New York to Juliana Airport in St. Maarten, utilizing an ONA aircraft and flightcrew, and an ALM cabin crew. Prior to departure, the captain noted that the public address system from the cockpit to the cabin was inoperative.

The aircraft was fueled to 28,900 pounds, which the captain noted was 900 pounds more than his planned requirement. The flight plan estimated an en route time of 3 hours 26 minutes and a time to fuel exhaustion of 4 hours 34 minutes.

Flight 980 departed New York at 1114. The climb and cruise were normal, though the cruise mach was reduced several times due to turbulence and weather. At 1424, the flight passed an intersection approximately 211 miles north of St. Maarten with 8,600 pounds of fuel remaining.

### Approaches to St. Maarten

Shortly after the flight was cleared to descend to 10,000 feet, air traffic control advised that the St. Maarten weather was below landing minimums. The captain diverted for San Juan at 1445. Within five minutes, however, Juliana Tower advised that the weather had improved to an estimated ceiling of 1,000 feet broken, 5,000 feet overcast, and 4 to 5 miles visibility in rain. The flight was given a new clearance to St. Maarten. The captain noted 5,800 pounds of fuel remained and estimated they would arrive at the ramp with 4,400 pounds.

The flight arrived over the St. Maarten radio beacon at 1515 and commenced an Automatic Direction Finding (ADF) approach. The crew did not sight the runway in sufficient time to align the aircraft for a landing. The captain then attempted two left-turn visual circling approaches. The first was abandoned due to poor alignment. On the second circling attempt, the captain was able to align with the runway but was too high and close in to maintain the proper descent profile without reducing power below acceptable limits. The captain stated that during the approaches, a moderate rain shower was in the area where he was turning on a base leg.

### Diversion and ditching

Following the third unsuccessful landing attempt, the captain returned to the St. Maarten beacon and elected to divert to St. Thomas. The flight was cleared to St. Thomas at 4,000 feet. The captain testified that during the climb, the fuel gauges and totalizer were erratic, but the totalizer momentarily stabilized at 850 pounds. The captain testified that he doubted this reading, believing there was no way the aircraft could have less than 2,000 pounds of fuel, and concluded the gauges were giving an erroneous reading.

At 1531, the flight contacted San Juan center. Two minutes later, the flight advised, "I'm a little short on fuel and I gotta get up," and was cleared to Flight Level 120. During the climb, the flight requested clearance to St. Croix, which was 11 miles closer. The captain indicated he used reduced power and airspeed in the climb in an effort to consume less fuel.

By the time the aircraft reached 7,000 feet, the captain decided he had to believe the low fuel gauge reading and requested a descent to 5,000 feet to establish visual contact with the water. He advised air traffic control of a possible ditching and called the purser forward to prepare the cabin. At 1547:40, the crew radioed, "we're ditching."

The captain leveled off momentarily at 500 feet to position the aircraft over a swell system, then descended in 100-foot increments. When the low fuel pressure lights flickered, he selected full flaps. The engines flamed out shortly after, and the captain flew the aircraft onto the water at approximately 90 knots with a 5- to 6-degree noseup attitude.

### Survival aspects

About 10 minutes before the ditching, the captain had instructed the purser to advise the passengers to don lifevests and prepare for a ditching. Because the cockpit microphone was inoperative, no direct instructions were given from the flight deck. The purser understood the instruction as a precautionary measure and assumed further orders would follow if a ditching were necessary. The cabin attendants demonstrated the lifevests and assisted passengers, some of whom had difficulty removing the vests from under their seats.

The navigator was sent to the cabin to assist and helped the purser move a 25-man liferaft from a forward closet to the galley. The navigator suddenly realized impact was imminent and shouted for everyone to sit down. The crewmembers in the galley were unable to fasten their seatbelts. Several passengers and the stewardess were still standing, and at least five others did not have their seatbelts fastened at impact.

Following impact, the forward main door was found jammed. The steward opened the galley exit door, but as crewmembers attempted to free the liferaft from spilled galley equipment, the raft inadvertently inflated. It pinned the first officer to the bulkhead and prevented the crewmembers from entering the main cabin.

The captain exited through the cockpit window and opened the left overwing exits from the outside. Most passengers escaped through the aft right overwing exit, which was opened by a passenger. The navigator and a passenger inflated an escape slide, which the main group of survivors gathered around. Helicopters from the U.S. Coast Guard, Navy, and Marine Corps rescued the survivors.

### What the investigation found

The National Transportation Safety Board found no malfunctions of the aircraft's systems, powerplants, or airframe. The total flight time to fuel exhaustion of 4 hours 35 minutes compared with remarkable accuracy to the flight plan's estimated endurance of 4 hours 34 minutes.

The Board determined that the flight arrived over the St. Maarten beacon with about 4,200 pounds of fuel, which was approximately 100 pounds below the FAA-prescribed alternate fuel requirement. During the subsequent 11 minutes of circling approaches, the aircraft was flown in a landing configuration at high power settings, consuming approximately 1,400 pounds of fuel. The Board concluded that visibility in the most essential area of the approach was far below the announced values due to the rain shower, forcing the approaches to be conducted too close to the airport.

Regarding the fuel gauges, the Board believed the 850-pound reading was the result of normal erratic behavior of the totalizer due to the low fuel state, aircraft attitude, and turbulence, rather than a malfunction. The Board noted that when the captain diverted to St. Thomas, he did not mention the low fuel condition to San Juan center, delaying his climb. Furthermore, he used a low-power, low-airspeed climb that was less efficient in terms of distance than a full-power climb, diminishing any opportunity to reach the alternate airport.

The Board also noted that the cabin attendants did not fully appreciate the gravity of the situation and were not given signals to brace for impact. The inflation of the raft in the galley denied passengers the use of that door for egress and preoccupied four crewmembers.

### Probable cause

The National Transportation Safety Board determined that the probable cause of the accident was "fuel exhaustion which resulted from continued, unsuccessful attempts to land at St. Maarten until insufficient fuel remained to reach an alternate airport."

The Board found that a contributing factor was the reduced visibility in the approach zone because of rain showers, a condition not reported to the flight.

The Board also found that the probability of survival would have been increased substantially if there had been better crew coordination prior to and during the ditching.