Maxim Pyadushkin Moscow

Russian aircraft manufacturer Sukhoi has started flight-testing the long-range version of its Superjet 100. But if the SSJ program is to become a success, the technical flaws that affect the baseline version must be conquered.

The first prototype of the SSJ 100LR made its maiden flight Feb. 12. The variant has a range of 4,578 km (2,845 mi.) compared to 3,048 km for the basic type. The long-range version can carry more fuel and is powered by NPO Saturn-Snecma SaM146-1S18 engines that provide 5% more thrust than the standard SaM146s.

According to United Aircraft Corp., Sukhoi Civil Aircraft Corp.'s parent company, the SSJ 100LR trials will take 3-4 months. Certification of this version is slated for 2014. Gazpromavia is signed on to be the first operator. The carrier, a subsidiary of Russia's energy giant Gazprom, placed an order for 10 SSJ 100LRs in 2011.

Sukhoi officials meanwhile say measures are underway to improve the appalling reliability record of the Superjets already in service. Because of a range of technical issues, four of Aeroflot's 10 SSJs were temporarily grounded. They were cleared to resume regular flight operations earlier this month. The pressure on Superjet's civil arm is mounting now that the first export deliveries to Indonesia-based Sky Aviation and Mexico-based Interjet are imminent. Laos-based Lao Central received its first aircraft Feb. 15.

Aeroflot stated in an internal presentation in January that its SSJ 100s were involved in 24 technical mishaps in 2012. The aircraft was therefore responsible for 40% of the total technical incidents for Aeroflot's fleet of 125 aircraft during this period. Most common were problems with the SSJ 100's air conditioning system. Other issues that cropped up frequently affected the aircraft's flight controls, landing gear, fire protection system and engines. Aeroflot's SSJ 100s have logged a total of 17,313 flight hours or 9,186 flights as of January.

But Andrey Nedosekin, Sukhoi Civil Aircraft's senior vice president for post sales support, says the major problems have been identified and repairs are already underway. A service bulletin addressing the erroneous engagement of the air leakage detection unit—a part of the overall air conditioning system—has been issued and implemented for all aircraft at the production site. Sukhoi announced that all necessary changes will be implemented across the operating fleet by summer.

Another service bulletin addressed a slat extension fault after a new design was validated during additional bench tests. According to Nedosekin, the corresponding design improvements were implemented on the four grounded Aeroflot SSJ 100s. A schedule to correct the balance of the affected aircraft is being worked out with all carriers, according to Sukhoi. The manufacturer will be compensating the airlines for financial losses incurred during the grounding.