Appreciation

The action in the movie is at some moments very tense and breath-holding. Loggia and Bakula nicely play their roles, along with the other secondary actors. The audiovisual quality is excellent and the air to air images are magnificent, most likely professional commercial footage. However, that compensates for the "amateur" special effects, that might remind you of the movie Airport. Also, too bad they don't give many precisions about the real event: no date is given at any time.

I give this movie 8 out of 10.
It is an excellent movie to watch with the family, and will keep you restless at key moments.

Things to notice

Here are the goofs and trivia for Mercy Mission: The Rescue of Flight 771.
In real life, Gordon Vette retired from Air New Zealand in the early eighties (1981 or 1982), so even in the movie, the event should have been depicted before that time, when the Boeing 767 was not yet on commercial service... nor the 747-400s seen at San Francisco, bearing a fresher United Airlines color scheme (larger and more "squeezed" characters).

Prior to departure, many planes are seen from the cockpit, among them a few Ansett Australia planes bearing the "Australian Flag", when the action occured in the early eighties (at the time Ansett used the "Star" livery).
I see an Australian Airlines plane in the ground cockpit scene at Fiji. Has Australian Airlines ever flown to Fiji? Did it even exist when the incident occured (early eighties)? Or was it still called TAA?

During the cockpit sequence, the engine needles (EPR, N1, N2) in the central video screens do not move, even though Captain Vette applies full thrust.
Air New Zealand Flight 308 is a Boeing 767-200 in all sequences (mostly stock footage from ANZ), except on take-off when it becomes a Boeing 737-200, and at the Auckland Airport apron, where it is a Boeing 737-300/400 of Australian Airlines. The titles are barely visible since the scene is at night.

Additionally, the hangar where Vette challenges one of his supervisors, in one of the first scenes, hosts a couple of Australian Airlines aircraft, minus titles.
In all the daylight sequences, the clouds seen from the inside the cockpit of the 767 are perfectly still. A poster was probably used. For the night sequences however, the clouds really move. In the case of the Cessna, the clouds from the outside are moving, but the use of background film is obvious.

The First Officer touches too many random and irrelevant buttons during the flight operations. For example, he sets the autopilot heading or course during the very final approach!

The take-off cockpit sequence was done (obviously) in a flight simulator.

You may be interested to know that...

As shown during the taxi sequence, the aircraft was baptized "Aotearoa", which is the Maori name of New Zealand and means "land of the long white cloud". It is one of the first 767-200s used by Air New Zealand. This can be noticed as the plane taxies to the runway... before it becomes a 737-200.
The major airport in the American Samoa is in a city called Pago Pago, which is actually pronounced "Pango Pango", as accurately depicted by the actors. The same thing can be said about Nadi, in Fiji, which is pronounced "Nandi".
When the air traffic controller stands up to warn Hudson about the Cessna declaring an emergency, you can see, right above his radar scope, a bumper sticker saying: "I AIR TRAFFIC CONTROL".

Gordon Vette has a cameo role near the end of the movie, as a bystander at Auckland Airport, tapping the back of what an IMDb user believes to be the real Jay Prochnow.

Here are the main differences between the real event and the movie depiction. This information comes from Stanley Stewart's excellent book Emergency! Crisis on the Flight Deck.

Jay departed Pago Pago for Norfolk Island in the night of December 21, 1978, and landed one day later (due to the International Date Change line crossing). The movie depicts his departure (and Frank's balked departure) as occuring after Christmas Day.

The only character names that were kept in the movie were Gordon Vette (probably as a token of gratitude from the film crew - his name is mentioned in the credits) and Jay, whose last name in real life was Prochnow.
Aboard what was really flight 103 (and not 308), there were also First Officer Arthur Dovey and Second Officer Gordon Brooks (later killed in the Mount Erebus, Antarctica crash on November 28, 1979). An Air New Zealand DC-8 First Officer, Malcolm Forsyth, flying off-duty as a passenger, later joined the three airmen.

The aircraft was a DC-10-30, registered ZK-NZS, and not a Boeing 767-200 as depicted in the movie. There are two accurate details, however: the flight's route was indeed a Nadi-Auckland run, and there were really 88 passengers.

Jay did make the trip all the way to Pago Pago with a fellow pilot, flying a separate Cessna 188 crop duster. The departure from Pago Pago is relatively accurate. The fellow's plane did experience difficulties on take-off, and its pilot was forced to ditch. It is interesting to note that, in real life, Jay landed back in Pago Pago after his colleague's ditching. In the movie, Jay is compelled to resume his departure to Norfolk Island immediately after witnessing Frank's ditching from the air.

It is believed that, on the second half of the movie, there are several scenes created for dramatic purposes, since the book makes no mention of them at all.

The planes

Flight 308 is a Boeing 767-200 operated by Air New Zealand, flying a Nadi - Auckland route. (NAN-AKL). Cessna 771 is a Cessna crop duster privately owned and operated, flying a San Francisco - Honolulu - Pago Pago - Norfolk Island - Sydney route (SFO-HNL-PPG-NLK-SYD) for a delivery flight.