Douglas DC-4 accident at New Orleans, Louisiana, 19 Dec 1946 (NC-88897)

Accident narrative

On December 19, 1946, at approximately 2258, Pan American Airways Flight 702, a Douglas DC-4 (NC-88897), collided with trees in the immediate vicinity of Moisant Airport in New Orleans, Louisiana. The aircraft and engines sustained considerable damage, but none of the 45 occupants were injured. The flight proceeded to Brookley Field in Mobile, Alabama, landing safely at 0105 on December 20.

### The flight

Flight 702 originated in Balboa, Canal Zone. A new crew of six boarded at Guatemala City, and the flight departed Merida, Mexico, at 2103 with 39 passengers and 2,000 gallons of fuel aboard. The company cleared the flight direct to New Orleans on an instrument flight plan at 8,500 feet, designating Lake Charles, Louisiana, and Mobile, Alabama, as alternates. Good weather was expected along the entire route, though instrument conditions were anticipated near New Orleans.

Captain Sidney A. Adger had 3,146 flying hours, including 1,000 in DC-4 equipment. First Officer Nicholas H. Lutz had 2,926 hours, with 164 in the DC-4.

### Sequence of events

Two hundred miles from its destination, the flight was flying "contact." The New Orleans airway traffic control center cleared the flight to Moisant Tower, instructing it to cross the Barataria fan marker at 1,500 feet or below. At 2132, an airways communication station advised the flight that the New Orleans barometer was falling rapidly.

At 2151, Captain Adger reported crossing the Barataria marker on instruments at 1,000 feet. The tower transmitted a 2100 weather observation reporting a 2,700-foot ceiling and four miles visibility, cleared the flight to land on Runway 10, and provided an altimeter setting of 29.93 inches.

The flight reported over the New Orleans range station, made a standard instrument let-down on the northeast leg, and flew a heading of 280 degrees toward the field. The aircraft passed over Moisant Airport to the right of Runway 10 in contact conditions. Captain Adger made a left procedure turn to land into the wind on Runway 10 but was unable to align the aircraft with the runway. He climbed and proceeded back out the northeast leg of the range.

At approximately 2218, the flight passed over the range station inbound for a second approach. The tower transmitted the 2218 weather observation, which included an indefinite ceiling, a 400-foot overcast, and visibility of 2 1/2 miles in moderate rain and light fog. Heavy rain obstructed visibility, and the landing was not completed. Captain Adger climbed to 500 feet and held a heading of 100 degrees for one minute.

Shortly after the second approach, the tower transmitted a 2228 weather observation reporting an indefinite 200-foot overcast and two miles visibility. Between 2228 and 2240, the Pan American dispatcher at Brownsville recommended Memphis, Tennessee, as an alternate, and the tower relayed the course and distance to the flight. At 2243, the tower reported an indefinite 300-foot overcast and a rapidly falling barometer. At approximately 2251, the flight reported holding at 2,000 feet northeast of the range station. At 2258, the tower reported a 300-foot broken ceiling and two miles visibility.

Sometime between 2228 and 2303, Flight 702 made a third approach. The flight missed the approach and struck trees near the airport boundary. The crew shortly after reported trouble with engines No. 1 and No. 2. The aircraft remained in the New Orleans area for 20 to 25 minutes. At 2321, the flight was cleared to Memphis, but Captain Adger requested the nearest landing place due to engine trouble. Engine No. 1 was shut down and its propeller feathered; Engine No. 2 was reduced to 20 inches manifold pressure due to excessive oil temperature and vibration. Air traffic control cleared the flight to Brookley Field in Mobile. The aircraft landed there safely at 0105.

### What the investigation found

Examination of the aircraft revealed considerable damage from flying through trees. Spanish moss and wood particles were found in the No. 1 and No. 2 engine nacelles, the oil coolers, and all three landing gear struts. Propellers No. 1 and No. 2 were out of track. The aircraft sustained a ruptured right inboard fuel tank, a damaged right horizontal stabilizer, a torn left de-icer boot, and a broken left main landing gear bungee system. Several antennas and the right landing light were missing. The Board found no evidence of mechanical failure prior to the aircraft striking the trees.

The Board noted that weather data available before departure indicated instrument conditions would be encountered in the New Orleans area, and that Lake Charles and Mobile—both designated as alternates—could expect similar conditions as they were in the same storm area.

Pan American's minimums for Moisant Airport were a 400-foot ceiling and two miles visibility, or a 500-foot ceiling and one mile visibility. The Board found that the first two approaches were made when reported weather was above these minimums. However, the third approach was made after the ceiling was reported below minimums and after the dispatcher advised proceeding to Memphis.

Evidence indicated Captain Adger knew the ceiling was below minimums. The traffic controller reported that Captain Adger stated, "You gave me a bum steer on weather. I am down to 300 feet and am not 'contact'." Tower personnel also observed the aircraft flying as low as 50 feet above the trees.

Captain Adger referred to his landing procedure as a "New York approach," designed to keep the field in sight while maneuvering under the overcast. The Board found that no precise or consistent pattern was flown after passing the range station, and no standard missed approach procedure was used.

The altimeters were tested and showed no significant error. The Board noted two possible sources of altimeter error—an incorrect static selector valve position or a failure by the crew to update the altimeter setting, which had dropped significantly—but stated there was no reliable evidence to make a finding on these possibilities.

### Probable cause

The Board determined that the probable cause of this accident was "the pilot's deliberate descent through an overcast to a dangerously low altitude in an attempt to land despite his knowledge that ceilings and visibility were below the minimums authorized by the Civil Aeronautics Administration."