A stretch of the Swearingen SA-26 Merlin it was designed to be stretched to seat 22 passengers and was called the SA226-TC Metro. Because FAA regulations limited an airliner to no more than 19 seats if no flight attendant was to be carried, the aircraft was optimized to carry 19 passengers but the name remained.
Swearingen Aircraft was in financial difficulties however, and late in 1971 Fairchild (which was marketing the Metro and building its wings and engine nacelles), bought 90% of Swearingen and the company was renamed Swearingen Aviation Corporation. It was at this point that the previously cash-strapped company was able to put the Metro into production.
The first airline to fly the new aircraft was Commuter Airlines based at Greater Binghamton Airport, Maine, New York.
Interestingly almost 20% of the total numbers built of various model Metroliner's has operated in Australia. New Zealand has had a number operating here too.
If my files are correct the first in NZ was ZK-SWA - a Metro II - for Air Albatross registered Dec 5 1983. SWB/SWC/SWD also served with AA until they collapsed in December 1985. Air Nelson, Eagle, Air Chathams and Airwork have also operated the Metroliner.
Today there are 3 passenger version; CIC/CID with Air Chathams and POB with Airwork, and 2 freighter versions POE/POF with Airwork, still flying.
At the 1987 Paris Air Show, Fairchild released details of proposed developments of the Metro designated the Metro V and Metro VI. These versions would have featured a longer fuselage with a taller "stand-up" cabin providing 69 in (180 cm) of interior height for passengers; a redesigned, longer wing; engines moved further out on the wing from the fuselage; a "T-tail" and various system improvements. A Merlin V corporate version of the Metro V was also planned. The Metro V was to be fitted with the same engines as the Metro 23 and the Metro VI was to be fitted with more powerful TPE331-14 engines. The Metro VI was shelved within months of being announced due to a lack of customer interest, but Fairchild did not proceed with the Metro V either.
One version that did see the light of day was the Metro 25, which featured an increased passenger capacity of 25 at the expense of the baggage space found in earlier models; the deletion of the left rear cargo door and the addition of a passenger door on the right-hand rear fuselage; and a belly pod for baggage. A Metro III was converted as a Metro 25 demonstrator, it flew in this configuration in October 1989. Also mooted but not built was the Metro 25J, which would have been another jet-powered aircraft with TFE731s in over-wing pods.
The 25 seat capacity was achieved by transferring baggage from the rear-fuselage area to an underbelly pod and installing six additional passenger seats. An extra five windows, a new door on the rear right-hand side, and the introduction of more, powerful engines make up the changes from the Metro III. The large rear cargo door was also deleted.
To meet FAR 25 regulations larger emergency exits, flight recorders, emergency lighting, cockpit "eyebrow" windows, flight-control redundancy, new nose wheel steering system, and strengthened wing spars were designed in.
1053 short + long body Merlin + long body Metroliner's were produced.
And for those who flew it, a reminder of the Metroliner's pre-flight checks!
Watch on youtube.com
Courtesy of Grayson Ottoway
Back to the ole real McCoy seat of the pants know ya plane rather the plane knowing you .. they weren't exactly designed with passenger comf
.. I knew someone may bring this up 
