Your question is vague, so the only crisis dealing with Berlin that I can think of would be the Berlin airlift. If this is the case JFK was not in office in 1949. He wasn't elected president until 1960. If you mean the Cuban crisis that is a different story.
President John F. Kennedy approached the Berlin Crisis, particularly the construction of the Berlin Wall in 1961, with a mix of firm resolve and diplomatic caution. He reaffirmed U.S. commitment to West Berlin, signaling strong support for its inhabitants and a willingness to confront Soviet aggression. During a televised speech in 1963, he famously declared, "Ich bin ein Berliner," expressing solidarity with the people of Berlin. Kennedy's administration focused on maintaining a strong military presence in Europe while seeking to avoid escalation into direct conflict with the Soviet Union.
The Berlin Wall and the Cuban Missile Crisis were both situations that defined the presidency of John F. Kennedy. Chairman Nikita Khrushchev of the Soviet was convinced that since Kennedy did nothing to stop the building of the wall that he would also do nothing about the placement of missiles in Cuba.
John Kennedy made the famous ich bin ein berliner speech in Berlin .
"I am a citizen of Berlin"
1963
John Kennedy was the President during this crisis.
The (JFK) bungled attempt to rescue Cuba from Castro. The Cuban Missile Crisis The Berlin Wall Crisis JFK's committing the USA to put a man on the Moon by the end of the decade.
at whitch terminal at JFK I find Air Berlin
President Kennedy is credited with resolving the Cuban Missile Crisis.President John F. Kennedy
Cuban missle crisis.
John F. Kennedy
President John F. Kennedy.