The creaky airplane headed into its final approach, 12 hours overdue and shuddering so fiercely that the cockpit door kept swinging ajar, its hinge screws dancing merrily in threadbare holes.

As the propeller craft of 1950s vintage descended over the North China plain, the emergency hatch suddenly sprang open wide enough for a Chinese peasant to thrust out his face for a bird's-eye view. With the plane bumping to a halt, plumes of runway dust swept through the cabin.

No one aboard registered more than a nervous titter, however, for at least this flying fossil of the Civil Aviation Administration of China (CAAC) landed intact.

Not every flight ends so well. During the past 14 months, China's state-run airline has piled up a record that makes the most fearless flier thankful to reach the ground. Among dramatic examples reported by CAAC or reliable foreign sources:

* In April 1982, 112 tourists were killed when a CAAC jet crashed into a mountain in bad weather near the resort city of Guilin.

* Last July, Chinese passengers and crew overwhelmed hijackers in a desperate midair melee that left a large hole in the side of the plane.

* On Christmas Eve, 23 persons died and 28 were injured when a CAAC aircraft burst into flames after a forced landing in Canton.

* Last January, a hijacker ordered a domestic CAAC flight to Taiwan, fatally shot the pilot, then was killed himself by an ax-wielding navigator.

* The next month, a CAAC jetliner landing in Fuzhou slid off the runway and was destroyed when the landing gear collapsed. No casualties were reported.

* Last month, six armed hijackers who forced a CAAC plane to South Korea sent the aircraft into wild gyrations when the crew tried to resist them.

As the disasters mount, China's flag carrier has been criticized by wary passengers and foreign airline industry officials who say that flying the friendly skies of CAAC can be high risk.

"I have great misgivings about CAAC's standards of maintenance and equipment," said Robert Scott, director of the Hong Kong branch of the International Federation of Airline Pilots Associations. "Their airports have few navigational aids, the fleet is badly outdated, their security is spotty and their crews lack modern training.

"Any westerner who goes on CAAC should know he's flying in an unsophisticated aviation environment," Scott added.

The criticism coincides with CAAC's flushest financial period in its 33-year history. Last year it recorded about $120 million in profits, and officials predict even higher earnings in 1983.

With passenger loads said to have increased by 20 percent yearly since 1979, CAAC plans to expand its domestic routes to absorb the growing number of foreign tourists--100,000 from the United States last year--who bring in much-needed foreign exchange.

Foreign passengers pay dearly to fly CAAC, which has a monopoly. Fares charged foreigners on domestic flights can run three times higher than what Chinese pay.

Critics say westerners accustomed to top aviation standards are getting shortchanged by an airline that scrimps on maintenance, ignores basic safety rules, offers few passenger services and operates in secrecy.

CAAC officials refused to be interviewed for this article.

Even under the best circumstances, flying in China can be an adventure. Of CAAC's 162 planes, most are Soviet-made, designed in the 1950s and said to be long past their prime. Less than a third of the fleet are jets, mostly older Boeings and British Tridents.

The interiors of some of these flying antiques are shabby, with seats loosened from their bolts and meal trays flopping. Light switches seem to be mainly for decoration. A trip to the toilet can end in a wrestling match with an unclosable door.

Flights often are canceled if not enough customers show up. Overbooking, however, poses little practical problem. A European businessman recalls how six Chinese were seated on collapsible canvas stools on a crowded flight last year from Inner Mongolia to Peking. "Seat belts? The chairs didn't even have backs," he said.

Frequent travelers are accustomed to unscheduled stops caused by bad weather. When darkness falls, they can expect to lay over--at their own expense--because few Chinese airports have radar and other navigational aids for night landing.

Inconvenience, however, is the least worry of an airline said by one European aviation specialist to be among the world's most contemptuous of safety standards.

Crews give no safety briefings on domestic flights, and usually there is no sign of oxygen masks, life jackets, fire extinguishers or written emergency procedures. Piles of freight sit unfastened on seats or in front of emergency exits. Foreign observers said many of the 23 passengers who died of suffocation or gas poisoning in the Christmas eve fire in Canton might have survived if they had been given oxygen masks and evacuation instructions.

After the Canton and Guilin accidents, Civil Aviation Administration Director General Shen Tu promised to tighten safety measures. But critics say any real improvement would cost more than the cost-conscious airline is willing to spend.

"Safety procedures are appalling," a foreign airline official said. "But CAAC is interested in hard cash, not winning safety awards."

Although mechanics keep a regular maintenance schedule, they reportedly bypass some costly servicing recommended by western plane builders.

Instead of replacing nonreusable air filters in one of the western jets, service crews simply remove the filters, wash them and replace them, foreign sources said.

A pilot who landed a Trident jet in Hong Kong last year was advised by the local ground crew to change his engine, which was malfunctioning. The plane's oil filter, according to sources, was loaded with metal filings, suggesting that the engine was shearing.

But the pilot ignored the advice and asked for permission to take off, the sources said. The tower refused after being told of the trouble. Then the pilot bought a new engine.

Of concern to foreign experts is the way crews handle hijackings. According to Director Shen Tu, crews are instructed to subdue air pirates if "absolutely sure" they can be resisted without danger to passengers.

But Scott, of the pilots' group, said CAAC's policy runs against international standards for handling such security problems--to submit to demands, get the plane on the ground and only then contemplate ways to overwhelm them.

When five Chinese youths armed with dynamite ordered a Shanghai-bound tourist flight to Taiwan last July, the pilot flew in circles until fuel was almost exhausted. Then, the crew led Chinese passengers in an attack on the hijackers with umbrellas and mop handles while the plane plunged. The pilot regained control and pulled the aircraft out of its dive, but the plane hit the runway so hard that the tires blew out.

Last month's hijacking to Seoul almost ended in calamity when the crew's resistance angered the hijackers. The navigator was shot in the knee when he tried to drive out the air pirates with a wooden staff. Then, while the pilot tried to trick them by landing in friendly North Korea, the copilot was caught sending emergency signals for help to a ground station.

"That was when [a hijacker] got hopping mad, seized the controls himself . . . , made the plane pitch and roll wildly and terrified both the passengers and crew members," said the official news agency.

CAAC decorated crew members on both flights for gallantry.