Saratov Airlines Flight 703 was a scheduled domestic passenger flight from Moscow to Orsk Airport in Russia that crashed shortly after take-off from Moscow Domodedovo Airport on 11 February 2018 in Stepanovskoye, Ramensky District. The Antonov An-148-100B serving the flight suddenly dived while en route to its destination, killing all 71 people on board. It was the deadliest crash involving the Antonov An-148 and the first commercial passenger flight crash involving the type.
The Russian Interstate Aviation Committee (IAC), which was responsible for the investigation of the crash, published the final report in 2019. They concluded that the crash was caused by multiple factors. The crews had decided not to turn on the pitot heaters even though the weather was conducive for icing. As the aircraft climbed, all three pitot tubes became blocked by ice, resulting in conflicting airspeed indications. The captain then quickly became fixated on resolving the issue and developed tunnel vision as he was unable to determine which reading was correct. Overwhelmed, he ignored warnings from his co-pilot, continued making a nose-down input, and caused the aircraft to dive and crash at high speed.
Aircraft
The aircraft involved in the accident was an Antonov An-148-100B built by Voronezh Aircraft Production Association, registration RA-61704, MSN 27015040004, powered by two Progress D-436 engines. It first flew in May 2010 and was delivered to Rossiya Airlines in June 2010. It had been involved in two previous minor incidents in service; an engine was shut down on 28 July 2013 after it surged in flight, and it suffered a nose wheel failure on take-off on 23 August 2013. The aircraft continued to operate with Rossiya until 2015. After years of storage, the aircraft had been leased to Saratov Airlines since February 2017, a year prior to the crash. The aircraft had flown about 16,250 hours and 8,400 landings against a designed life of 20,000 hours.
The aircraft had been involved in several previous incidents during service. In December 2010, the aircraft was struck by a snow-removal vehicle while being parked at Pulkovo Airport, causing significant damage to the wing. The aircraft was quickly repaired and went back to service on that same month. Two minor issues were also noted; an engine was shut down on 28 July 2013 after it surged in flight, and a nose wheel failure occurred on take-off on 23 August 2013.
The maintenance logbook indicated that prior to the flight, the aircraft had suffered some deferred defects, including a fuel-pump failure on No.2 engine. Despite the numerous faults, the aircraft was still allowed for service.
Passengers and crew
According to the flight manifest, Flight 703 was carrying 65 passengers and 6 crew members. Most of the passengers were residents of Orenburg. Russian news agency TASS reported that there were three children aboard the flight. The Russian Ministry of Emergency Situations said that all but two of the passengers were Russian citizens. The Azerbaijani community in Orsk confirmed that an Azerbaijani businessman was on board, while the Swiss embassy reported that a Swiss engineer was among the passengers.
The cockpit crews were consisted of:
- Captain Valery Gubanov (51), who had accumulated 5,000 hours of total flying experience, of which 2,800 were on the Antonov An-148. However, he had logged only 58 hours as pilot in command on the aircraft. He graduated from the Tambov Higher Military Aviation School in 1991 and served in the Russian Army until 2001, flying the Antonov An-12. He then worked as a pilot for the Russian Interior Ministry until 2005 before taking a three-year break from flying. He entered the civil aviation industry in 2008 and joined Saratov Airlines in 2011. His medical certificate had expired two days before the accident.
- First Officer Sergei Gambaryan (35), who had accumulated a total flying experience of 860 flight hours, of which 720 were on the type. He graduated from Leningrad aviation technical school in 1993 and worked in an air transport organization for a short period before spending 11 years as a flight attendant in various Russian airlines. He eventually joined piloting in 2013 through a training programme held by South Ural State University.
Accident
Flight history
Flight 703 was a regularly scheduled domestic passenger service from Moscow's Domodedovo Airport to Orsk Airport in Orsk, a city near the border to Kazakhstan and one of the most important industrial cities in Orenburg Oblast. The flight was operated by Russian regional carrier Saratov Airlines. At the time, it was the only flight from the Russian capital to Orsk. On 11 February 2018, the flight would be operated by one of the airlines' Antonov An-148 fleet, the RA-61704. The scheduled departure time from Moscow was 14:00.
Prior to the flight to Orsk, the aircraft was flown for a service flight from Saratov to Moscow, operating as Flight 760. Among the deadheading crew were Captain Gubanov and the rest of the cabin crew members, while First Officer Gambaryan would later catch up in Moscow. The aircraft arrived in Moscow at 10:02 a.m., arriving 5 hours late from its scheduled arrival due to delays during flight preparations in Saratov.
Preparation
After arriving in Moscow, the flight crews went to the airport for a pre-flight medical check, which they both passed. They later received the updated weather forecast for the flight. The on-duty forecaster explained that the pilots should watch out for moderate snow and severe icing while flying. The pilots then arrived at their aircraft, and Captain Gubanov started inspecting the Antonov An-148 for signs of ice. Following a walk around the aircraft, he used a ladder to inspect the upper surface of the left wing and concluded that no de-icing procedure was needed for the flight.
The aircraft was loaded with 472 kg of cargo and 561 kg of baggage. A total of 65 passengers boarded the plane. Both pilots went to the cockpit and started the pre-flight briefing.
After completing the boarding process, the flight crews started the "before engine start" checklist. While going through the checklist, the flight crews noticed that a message had appeared on the main display, informing them on a fault on the aircraft. First Officer Gambaryan commented "this is a fault, it was like this yesterday too", and Captain Gubanov merely responded with a simple "uh-huh."
The crew then proceeded with the next checklists and started to taxi to runway 14R. After being cleared to line up and wait, the crew ran through the "at line up checklist" while waiting. Finishing the checklist, First Officer Gambaryan stated "checklist complete, just the pitot probes left", referring to the activation of the pitot heaters. Captain Gubanov answered "pitot probes, good...".
Soon after, Flight 703 received take-off clearance from the ATC. The aircraft took off from Domodedovo at 14:21 local time, approximately 20 minutes late from its scheduled departure.
Start of failure
For the first three minutes after take-off, the aircraft was climbing normally. At 11:24:10 local time, the aircraft's recorded airspeed started to fluctuate. While climbing through an altitude of 1,100 meters, two of the aircraft's airspeed channels, the first probe and the standby probe, began showing different readings. Around 15 seconds later, all three airspeed indicators started to disagree with each other. The crew didn't notice yet as they were going through another flight checklist and were focusing instead on getting further permission to increase their altitude. At this point, the aircraft was still put in a climb as the crew got the required clearace to FL70 and later to FL110. The ATC granted the pilots request to climb to FL110. Shortly after, the An-148 warning system gave the crew "COMPARE AIRSPEED" alarm. The airspeed reading on Captain Gubanov's side was on 457 knots, while the standby probe read 430 knots. This prompted First Officer Gambaryan to check on whether they had the correct airspeed reading.
Several seconds later, the warning ceased. The airspeed on the first probe had converged within 5 km/h with the reading on the second probe. Satisfied, First Officer Gambaryan stated that the matter was settled, and the crew went back to their previous task. However, the airspeed diverged again for the second time. The first probe had its airspeed reading at 490 km/h before falling, while the standby probe had risen to 440 km/h. Since the difference between the readings on the first probe and second probe were within 10 km/h, no warning sounded. Captain Gubanov had been watching the fluctuating airspeed and started to be cautious.
Wanting to hold the airspeed, he set the autopilot at 460 km/h. The aircraft continued to climb normally with both probes giving different readings, rising and falling intermittently. Despite of it, the pilots didn't compare both probes and kept continuing with the flight.
First descent
Around 11:25 a.m, while climbing through an altitude of 2,000 meters, the "airspeed compare" warning sounded again for the second time. Captain Gubanov's probe showed a rapidly decreasing indicated airspeed, while the reading on the standby channel started to catch up and rose quickly. Alarmed with the falling airspeed, Captain Gubanov put the aircraft into a rapid descent by pushing the nose down, wanting to chase the speed he believed he was losing, causing the autopilot to disconnect. The aircraft pitched from 5 degrees up to 5 degrees down, g-load eased at 0,5 G and the aircraft descended at a rate of 20m/s. Gubanov's input caught First Officer Gambaryan off guard, causing him to try correcting the input by himself. Gubanov's airspeed display later showed the reading from the standby probe, in which the airspeed had jumped by 100 km/h. Meanwhile, the irregular speed warning had finally ceased.
The autothrottle was turned off and the thrust was pulled back towards idle. First Officer Gambaryan, whose airspeed display was showing the correct value, queried Gubanov's decision to pitch down, which he found perplexing due to the high speed of the aircraft. Gubanov, trying to understand the situation, kept making the nose down input. The actual airspeed, meanwhile, had been creeping towards the overspeed limit of the aircraft as the aircraft kept gaining speed. First Officer Gambaryan pulled the nose up a bit and managed to arrest the descent. Captain Gubanov, sensed that something was wrong with the aircraft, started to feel stressed with the condition.
The aircraft then started gaining altitude as it began to climb again. The overspeed warning ceased and the airspeed started to gradually decrease.
Crash
The aircraft was nearly reaching an altitude of 1,900 meters when the indicated airspeed on Captain Gubanov's display, which had been showing the reading from the standby probe, had dramatically fallen steeply from 480 km/h to around 300 km/h. First Officer Gambaryan's probe had also showed a significantly decreasing airspeed, from 440 km/h to 400 km/h. The airspeed continued to drop, causing Captain Gubanov to freak out. He then immediately put the aircraft into a descent by pitching the nose down again, this time at 16 degrees. First Officer Gambaryan, confused by Gubanov's abrupt input, asked him again on why he put the aircraft into a descent since the aircraft was flying normally, causing Gubanov to snap back at him and told him to stop talking.
Few seconds later, the aircraft's fly-by-wire system declared complete failure on all airspeed readings and deemed all of them invalid. The last two surviving probes had differed on their readings, reaching a difference of 36 km/h. The system then reconfigured the aircraft: pitch sensitivity doubled and autonomous nose-down input. Meanwhile, Captain Gubanov saw that the indicated airspeed continued to drop, now reaching only 200 km/h. Panicked by the reading, he doubled down on the pitch, making a nose-down input of 30 degrees below the horizon. First Officer Gambaryan alerted Gubanov that the aircraft was rapidly losing altitude. Gubanov yelled at him, ignoring his warning.
As the aircraft came hurtling down at a speed of more than 50 m/s, the aircraft's ground-proximity warning system blared, warning the crew of their impending crash with terrain. Roughly at an altitude of 1,200 meters, First Officer Gambaryan decided to intervene by making a nose-up input, even though Captain Gubanov kept pushing the aircraft towards the ground. Gubanov, startled by his co-pilot's input, ordered him to stop making the input. The airspeed finally reached the overspeed limit, causing the alarm to blare again.