U.N. peacekeepers and crew members struggled to evacuate the aircraft before the DC-9 went up in flames near a bustling outdoor market.
"The crew managed to save the majority of the passengers with the help" of peacekeepers, said Dirk Cramers, a spokesman for the private Congolese company Hewa Bora Airways.
The remains of the cockpit and tail rose over the flattened fuselage. Rescue workers with tractors, trucks and shovels searched for survivors as the peacekeepers sprayed the wreckage with hoses.
Cramers put the death toll at 21 and said "most of the victims were people on the ground."
The airline is "still trying to count the number of victims and wounded, but until now none of the 79 people on the official list of passengers and crew have been found dead," he said.
The Red Cross said 113 people had been injured and were being treated in local hospitals and clinics.
Witnesses reported many bodies at the crash site in this city in eastern Congo.
"We have already picked up many bodies dozens of bodies. There are a lot of flames, which makes it difficult to know if the bodies we are picking up are those of passengers of the plane or else passers-by or people that lived in the area where the plane crashed," said regional Gov. Julien Mpaluku.
Rescue workers carried about 20 bodies, many on stretchers, Anna Ridout of the aid agency World Vision said.
"I talked to a man who rescued seven people, including a 6-month-old baby, from an exit door. They were still conscious and moving," Ridout said. "But he couldn't go any further because he couldn't see anything. There was too much smoke."
Congo, which is struggling to emerge from a 1998-2002 civil war, has experienced more fatal crashes since 1945 than any other African country, according to the nonprofit Aviation Safety Network.
Last week, the European Union added Hewa Bora to its list of airlines banned from flying in the EU.
Federal Aviation Administration spokeswoman Alison Duquette said no Congolese airlines now fly into the U.S., although they are not banned from doing so.
World Vision, whose staffers when to the scene about a half-mile from its office, said in a statement that the plane "failed to leave the ground," plowing "through wooden houses and shops in the highly populated Birere market."
A former pilot, Dunia Sindani, was among the surviving passengers. He told a local radio station that the plane suffered a problem in one wheel possibly a flat tire and did not have enough power to lift off.
One of the plane's pilots reported that an engine died as the plane taxied down the runway, Gov. Mpaluku said. When the pilots tried to brake, a tire failed as well, the governor said.
It was unclear if weather played a part in the crash. It had stopped raining about one hour before the DC-9 took off at about 3 p.m., residents said.
Goma's runway was partially blocked and effectively shortened by lava from a 2001 volcanic eruption. The plane appeared to have burst through a fence separating the runway from a market district of wooden houses and cement shops where sugar, avocado, flour and fuel are sold.
The jetliner had been headed to the central city of Kisangani and then to the capital, Kinshasa, 700 miles to the west.
President Joseph Kabila expressed condolences to the affected families and called for an investigation.
The DC-9, an aviation workhorse for decades, has been involved in a number of accidents, including ValuJet Flight 2553, which plunged into the Florida Everglades on May 11, 1996, killing all 110 people aboard.
On Jan. 21, 2007, a Northwest Airlines DC-9 went off the runway in Milwaukee. The accident was due to an explosion in one of the engines, forcing the pilot to abort takeoff. Of the 104 people aboard, only one injury was reported.