Accident McDonnell Douglas DC-9-33CF N935F,
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Date:Saturday 2 May 1970
Type:Silhouette image of generic DC93 model; specific model in this crash may look slightly different    
McDonnell Douglas DC-9-33CF
Owner/operator:ALM - Antillean Airlines
Registration: N935F
MSN: 47407/457
Year of manufacture:1969
Total airframe hrs:2505 hours
Engine model:Pratt & Whitney JT8D-9
Fatalities:Fatalities: 23 / Occupants: 63
Aircraft damage: Destroyed, written off
Location:48 km ENE off St. Croix, Virgin Islands [Caribbean Sea] -   Atlantic Ocean
Phase: En route
Nature:Passenger - Scheduled
Departure airport:New York-John F. Kennedy International Airport, NY (JFK/KJFK)
Destination airport:Sint Maarten-Juliana Airport (SXM/TNCM)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
ALM flight 980, a McDonnell Douglas DC-9-33CF, ditched into the Caribbean Sea after running out of fuel. Forty of the 63 occupants survived the accident.
The aircraft was being operated under terms of a lease agreement by Overseas National Airways (ONA) on behalf of ALM - Antillean Airlines. Flight 980 was a regular service from New York-JFK International Airport to Juliana Airport on the island of St. Maarten.
Prior to departure the captain calculated that the flight would burn 21000 pounds of fuel. The total amount of fuel on board was 28900 pounds, which translated to an endurance of 4 hours and 34 minutes.
Bulletins received by the captain on the morning of the flight established a new company requirement for fuel planning purposes. The minimum estimated fuel on arrival at destination (EFA) for a nonstop flight to St. Maarten was established as 7000 pounds, which meant the aircraft's fuel exceeded the planned requirements by 900 pounds.

Flight to St. Maarten
The flight left the terminal at 11:02 hours local time and departed on runway 13R at 11:14. At the time power was applied for takeoff, the fuel totalizer read 28450 pounds. The aircraft climbed to the initial cruising altitude of FL290.
At 13:36 the aircraft descended to FL270 followed by a descent to FL250 due to turbulence.
At 14:24, the flight passed Guava Intersection, approximately 211 miles north of St. Maarten, with 8600 pounds of fuel on board. The captain estimated that they would arrive at St. Maarten at 15:00 with 6000 pounds of fuel.
Shortly after ALM 980 was given a final descent clearance to 10000 feet, San Juan Air Route Traffic Control Center (ARTCC) advised that the St. Maarten weather was below landing minimums. The captain requested a repeat of that information and then asked for clearance to San Juan at FL210. At 14:45, the flight diverted for San Juan. However, during the next five minutes, Juliana Tower at St. Maarten advised the flight that the weather had improved to an estimated ceiling of 1000 feet broken, 5000 feet overcast and 4 to 5 miles visibility in rain. With these weather conditions, flight below 1000 feet presumably could be accomplished by visual reference to the ground. The flight was given a new clearance to St. Maarten at 14:51, with permission to descend to 10000 feet at pilot's discretion. The captain noted at this point that 5800 pounds of fuel remained, and estimated that they could arrive at the ramp at St. Maarten at 15:05 with 4400 pounds of fuel. ALM 980 was cleared to descend to 6000 feet, and subsequently cleared for an approach to Juliana Airport at approximately 15:00.
At approximately 15:08, the flight reported level at 2500 feet and the tower controller advised that the weather was 800 feet scattered, estimated ceiling 1000 feet broken, 5000 feet overcast, visibility 2 to 3 miles. The crew commenced the approach at 15:15, and they were cleared to make any turns desired in case of a missed approach. On this approach the crew did not sight the runway in sufficient time to align the aircraft for a landing, and a left turn was made to reposition the aircraft, by visual reference to the ground, for another landing attempt at approximately 15:19. This attempt was also unsuccessful because of poor alignment with the runway. During both of these approaches, the aircraft had been flown with 25° flaps, landing gear down, and 140 knots airspeed.
After the second landing attempt was aborted, the captain selected full flaps and maintained 128 to 130 knots airspeed for the third approach. On this occasion, he was successful in aligning the aircraft with the runway, but he 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, but generally visual contact with the field was maintained.
The weather remained relatively unchanged throughout this period.
Following the third unsuccessful attempt to land, the captain returned to the St. Maarten NDB and elected to divert to St. Thomas.

Low on fuel
The flight was cleared to St. Thomas via direct route at 4000 feet by the Juliana Tower and, at 15:31 ALM 980 was instructed to contact San Juan ARTCC. The captain testified that during the climb to 4000 feet the fuel gauges and totalizer were erratic, but the totalizer indication stabilized momentarily at 850 pounds while the aircraft was level at 4000 feet.
The captain stated that fuel cross-checks had been made en route, and no discrepancies had been noted until after the departure from St. Maarten. His last recollection of fuel quantity was 3800 pounds, which he testified he had observed when the aircraft was on the downwind leg of the third landing attempt. He testified that after the reading of 850 pounds was observed, the crew concluded that this was an erroneous reading.
Radio contact with San Juan ARTCC was established at 15:31. The flight was cleared to FL120, and during the climb requested clearance to St. Croix, which was 11 miles closer. The captain indicated that he used reduced power and airspeed in the climb in an effort to consume less fuel. At 15:38, in response to a request to descend, the flight was cleared to 5000 feet.
Less than 1 minute later, the captain reported to the San Juan controller, "Okay there’s a possibility I may have to ditch this aircraft, I am now descending to the water." He also called the purser forward and told him to prepare the cabin for ditching. During the next several minutes, the crew inquired about their position and the availability of assistance, and they were apprised of the rescue efforts which were already in progress.

Ditching and evacuation
At 15:47, they stated, "Nine eighty roger... ah... we’re ditching." The captain leveled off momentarily at 500 feet and positioned the aircraft over an established 'swell system.' He then descended in 100-foot increments, pausing momentarily to improve his depth perception. At approximately 20 feet, he lowered 15° flaps and allowed the airspeed to decrease from the previously maintained value of 145 to 150 knots.
When the low fuel pressure lights flickered, he selected full flaps. Shortly after this, the engines flamed out, and he flew the aircraft onto the water at approximately 90 knots while maintaining the aircraft body angle at 5-6° noseup.
Following impact, the purser and the navigator attempted to open the forward main passenger door, but found it to be jammed and inoperable. These two crewmembers then moved to the galley area where a third crewman, the steward, had already opened the galley exit door and at least one passenger had made her escape through the galley door. The three crewmen attempted to free the raft from the galley equipment which had spilled to the galley floor. They had just been joined by the first officer in this effort when the raft inadvertently inflated. The inflated raft pinned the first officer to the galley bulkhead, and prevented the other crewmembers from entering the main cabin area. These four crewmembers exited through the galley door. The captain was aware of the difficulties in the galley area, and entered the water through the cockpit window. He swam to the left overwing exits, opened them from the outside, and assisted two passengers out of the aircraft. The captain then glanced through the cabin for additional passengers but saw none. Most of the passengers exited through the aft right overwing exit, which was opened by a passenger who was seated next to it.
The navigator found an emergency escape slide floating in the water and, with the help of a female passenger, inflated it. The first officer, who had no lifevest, climbed on top of the slide and assumed command of the main group of survivors who gathered around the slide. Belts and ties were used to provide additional handholds for the people.
Although none of the five 25-man rafts on board the aircraft was deployed, several rafts were air-dropped at the ditching site. The U.S. Coast Guard Grumman HU-16 Albatross, an amphibian aircraft, dropped two rafts but both fell too far away to be reached. In addition, a Skyvan dropped two rafts in the area. The captain swam to one raft and the navigator reached the other, but neither was able to maneuver his raft back to the main group.
Recovery of the survivors by helicopter began approximately one and a half hours after the ditching, and the last survivor, the first officer, was picked up about 1 hour later.
Weather in the area during the rescue operation was estimated to be 400 to 500 feet overcast and visibility as low as three-eighths of a mile in rain. The aircraft sank in water more than 5000 feet deep, and was not recovered.

PROBABLE CAUSE: "The Board determines that the probable cause of this accident was fuel exhaustion which resulted from continued, unsuccessful attempts to land at St. Maarten until insufficient fuel remained to reach an alternate airport. 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 finds that the probability of survival would have been increased substantially in this accident if there had been better crew coordination prior to and during the ditching."

Accident investigation:
Investigating agency: NTSB
Report number: NTSB/AAR-71-08
Status: Investigation completed
Duration: 11 months
Download report: Final report




Revision history:


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