Pan Am Flight 214
| Pan Am Flight 214 | |
|---|---|
 The crashed Boeing 707 (rear) with two identical machines before delivery |
|
| Accident summary | |
| Accident type | Structural failure after lightning strike |
| place | Elkton , Maryland , United States |
| date | December 8, 1963 |
| Fatalities | 81 |
| Survivors | 0 |
| Aircraft | |
| Aircraft type | Boeing 707-121 |
| operator | Pan American World Airways |
| Mark | N709PA |
| Surname | Clipper Tradewind |
| Departure airport | Isla Verde International Airport , San Juan , Puerto Rico |
| Stopover | Friendship International Airport , Baltimore , United States |
| Destination airport | Philadelphia International Airport , Philadelphia , United States (not reached) |
| Passengers | 73 |
| crew | 8th |
| Lists of aviation accidents | |
On December 8, 1963, a Boeing 707-121 crashed on Pan-Am Flight 214 over the US state of Maryland after lightning struck the aircraft and exploded the fuel gases in a wing tank . All 81 occupants were killed in the crash.
plane
The crashed Boeing 707 (Code: N709PA) was the third machine of this type of aircraft ( serial number : 17588/3) and was on 15 August 1958 as the first jetliner to the airline Pan American World Airways delivered. By the time the accident occurred, the machine had completed 14,609 flight hours.
The first six Boeing 707s (all operated by Pan Am ) were not equipped with so-called “ static discharge wicks ”. These bars, which are mounted on the trailing edges of the wings and control surfaces , prevent electrostatic charging in flight and divert the voltage picked up in the event of a lightning strike.
the accident
The Boeing 707 operated a scheduled flight from Isla Verde International Airport in San Juan ( Puerto Rico ) to Philadelphia International Airport . A scheduled stopover was planned at the Friendship International Airport in Baltimore .
The aircraft landed in Baltimore at 19:35 local time, where refueling took place. The tanks were checked for any leaks. At 8:24 p.m., the plane took off for the leg to the Philadelphia airport, around 140 kilometers away . The rotating radio beacon (VOR) in New Castle , which is about halfway between Baltimore and Philadelphia, was overflown at 8:42 pm. The pilots received the information from the approach control that there was a thunderstorm with strong winds at the destination airport . The air traffic controller advised against landing and pointed out that five commercial aircraft were already in holding patterns. The crew decided to circle west of the New Castle radio beacon at 1,520 meters (5,000 feet ) until the thunderstorm passed . The controller announced that clearance for landing would probably be given around 9:10 p.m. Meanwhile the weather front was approaching the aircraft.
At 8:58 p.m., lightning struck the left wing and caused the kerosene- air mixture to explode in the left reserve tank. As a result of the explosion, the wing was torn open, so that its outer part broke away. The crew made an emergency call at 8:58:56 pm (“Mayday, Mayday, Mayday. Clipper 214 out of control. Here we go.”) . The co-pilot of a Douglas DC-8 , which was in the same holding pattern but 300 meters (1,000 feet) above the Boeing 707, reported to the air traffic controller that the machine was crashing while burning (“Clipper 214 is going down in flames.”) .
During the crash, all four engines and other components tore off the airframe. Before the impact, the fire jumped from the left to the right wing. At 8:59 p.m., the plane hit a field about two miles east of the town of Elkton , on the border between the states of Maryland and Delaware . The tip of the left wing was found 2.9 kilometers from the main wreck. 600 pieces of debris were recovered outside the impact crater. They were spread over an area approximately 6.5 kilometers long and 1.6 kilometers wide.
Cause of accident
Eyewitnesses observed from the ground that the machine was struck by lightning before it crashed in flames. The debris from the left wing and the shortwave antenna that had been torn off from the vertical stabilizer showed numerous small, punctiform craters in which the metal had melted. In the outer section of the left wing, the lightning penetrated the hull completely and left a hole about five millimeters in size in the surface.
The explosion occurred in the left reserve tank. This tank had not been refilled in Baltimore and contained only a small amount of the Jet B fuel taken up in San Juan . The final report published in 1965 left it open as to whether the lightning first ignited the fuel vapors in the outer expansion tank or vent surge tank , in the reserve tank or in the outer valve of the tank ventilation system . Investigations carried out later indicated that the initial ignition took place in the left vent valve, which was located near the reserve and equalization tanks. The flames broke through the valve and advanced through the vent pipes into the left reserve tank. During the crash, further gas explosions occurred in the reserve tank on the right wing and in the center tank , damaging the filled main tanks in both wings. The fuel pouring out of them also ignited.
The Federal Aviation Administration (FAA) issued a number of recommendations and guidelines in December 1963, which were then established as binding standards. These included:
- The retrofitting of all jet airliners with “static discharge wicks” in order to avoid electrostatic charging.
- Structural changes to the expansion tanks (ventilation tanks) of the Boeing 707 so that their upper side is no longer directly adjacent to the outer shell of the wing.
- Modifications to the vent outlets to prevent the spread of flames.
- Improved ventilation in the tank ventilation system to remove fuel gases from the tanks and pipes more quickly.
- In order to reduce the formation of explosive gas mixtures, Jet B should no longer be used in commercial aviation . Due to its very high gasoline content, it has a very low flash point.
See also
Web links
Individual evidence
- ↑ Production list of the Boeing 707
- ↑ a b c d e f g h i Civil Aeronautics Board, Pan American World Airways Inc., Boeing 707-121, N709PA near Elkton, Maryland, December 8, 1963
- ↑ Federal Aviation Administration, Safety Recommendations Boeing 707-121, N709PA accident Elkton, Maryland, December 8, 1963 (PDF) ( Memento of the original from April 15, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b c Aircraft disasters, David Gero, Stuttgart 1994
- ↑ a b c ICAO Aircraft Accident Digest 15 Volume II, Circular 78-AN / 66, pp. 121-133 (PDF)
Coordinates: 39 ° 36 ′ 28 " N , 75 ° 47 ′ 20" W.