PSA Flight 182

Pacific Southwest Airlines (PSA) Flight 182 was a Boeing 727-214 commercial airliner, registration, that crashed with a private Cessna 172 light aircraft over San Diego, California on September 25, 1978. 
It was Pacific Southwest Airlines' first fatal accident. The death toll of 144 makes it the deadliest aircraft disaster in California history. Until the crash of American Airlines Flight 191, it was also the deadliest plane crash in U.S. aviation history.
Both aircraft crashed into North Park, a San Diego neighborhood, killing all 137 people on both aircraft and seven people on the ground in houses, including two children. Nine others on the ground were injured and 22 homes were destroyed or damaged by the impact and the spreading of debris.
The Boeing 727 flew in on top of and behind the Cessna, unbeknownst to the Cessna pilots. The larger 727's right wing flaps and left main landing gear collided with the Cessna, which immediately exploded and fell to the ground below in flames. The burning PSA continued on for another few kilometeres before crashing in a residential area with high vertical speed and exploding, killing everyone on board instantly.