The following paper,
"It is now well known that modern microelectronic devices can suffer from single event effects caused by cosmic radiation neutrons in the atmosphere. The phenomenon has been observed both on ground and at aircraft altitudes. The neutron flux at aircraft altitudes (<15 km) is large enough to make the neutron single event effects an issue of reliability in aircraft electronics. The most studied device type is static random access memories (SRAM) since those devices have a very high density of transistors, making them sensitive to particle radiation. The cosmic ray neutrons are produced by the charged primary cosmic radiation in the earth's atmosphere. Thereby the atmospheric neutron flux is certainly influenced by solar activity and space weather. Experiments have earlier been made to characterise the neutron radiation environment in the atmosphere. Rapid increases in the neutron flux have been correlated to solar events. We have performed in-flight measurements of single event upsets in SRAM using a component upset test equipment (CUTE). The in-flight measurements aim at verifying ground based accelerated device testing. The CUTE experiments are carried out on commercial airliners (SAS) on intercontinental flights at high altitude. During the CUTE experiments the upset rate varies between flights. These variations can possibly be explained by space weather."
Cosmic Ray Effects on Micro Electronics (CREME96).