Iran Air B722 near Uromiyeh on Jan 9th 2011, impacted terrain during go-around

Last Update: November 14, 2017 / 15:22:48 GMT/Zulu time

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Incident Facts

Date of incident
Jan 9, 2011

Classification
Crash

Airline
Iran Air

Flight number
IR-277

Departure
Tehran Mehrabad, Iran

Destination
Uromiyeh, Iran

Aircraft Registration
EP-IRP

Aircraft Type
Boeing 727-200

ICAO Type Designator
B722

Airport
Urmia Airport, Urmia

Airport ICAO Code
OITR

EP-IRP broken up on the ground(Photo: Reuters/IRNA/Aliasqar Shadjoo)An Iran Air Boeing 727-200, registration EP-IRP performing flight IR-277 from Tehran Mehrabad to Uromiyeh (Iran) with 96 passengers and 9 crew, was on final ILS approach to Uromiyeh's Urmia Airport runway 21 in fog and snowfall around 19:45L (16:15Z). The crew went around but the airplane impacted terrain near Terman village about 8nm southeast of the airport (approximate position N37.558 E45.171) and broke up in six major parts. 78 occupants are confirmed dead (77 identified), 27 occupants were hospitalised with a number in critical condition.

The Vice governor of West Azerbaijan province of Iran said, that the airplane was on short final when the crew declared emergency due to a technical problem explaining they could not land at Urmia in these circumstances and requested to return to Tehran. During the go-around the aircraft lost height for unknown reasons and impacted terrain.

Iran's Transport Ministry said, that there was no emergency. According to tower tapes the pilot aborted the approach when he could not establish visual contact with the runway at decision height and went around indicating they wanted to return to Tehran.

On Jan 11th the Transport Ministry said, the last missing occupant was found underneath the belly of the aircraft and was recovered in the evening of Jan 11th. Of the 93 passengers and 12 crew 27 people have been taken to hospitals, 78 have perished.

On Jan 13th the Transport Ministry said that the aircraft was on the VOR/DME ILS Procedure 1 within 5nm from touch down when the aircraft went around, the crew reporting no reason for the go-around but announcing to return to Tehran Mehrabad. The aircraft intercepted radial 150 of the VOR. About 13nm southeast of the airport the airplane suddenly turned around and headed directly for the airport but lost height and impacted ground about 8nm from the airport.

On Jan 24th 2011 the Transport Ministry reported that first results off the flight data recorder suggest a loss of power from the engines (JT8D).

On Jan 10th 2011 the Civil Aviation Authority said, that both black boxes (flight data and cockpit voice recorders) have been recovered and first analysis has begun.

The Uromiyeh forensic medicine reported on Jan 10th to have received 77 bodies, 73 thereof are already identified. Uromiyeh hospitals reported on Jan 10th that they are treating 26 patients that were rescued out of the aircraft, 2 or 3 are still in critical condition.

Aviation sources in Iran suggest that engines #1 and #3 (left and right hand engine) may have lost power during the missed approach procedure at about 13 DME from the airport.

Uromiyeh's Airport features a runway 03/21 of 3250 meters length, there are ILS instrument approaches only to runway 21 (21: ILS, VOR/DME, VOR, NDB, 03: VOR/DME).


Some time in 2017 Iran's CAO published their final report in Persian.

Due to the construction of the PDF file, which does not permit to copy and paste the text due to a lot of digits and other characters randomly thrown in and thus does not permit to translate the text via translation software, The Aviation Herald was unable to provide a summary with any degree of certainty, a native Persion reader offered and provided assistance leading to the following translation and summary:

bad weather conditions for the aircraft and inappropriate actions by cockpit crew to confront the situation is the main cause of the accident

Contributing factors were:

- the old technology of aircraft systems
- absence of a suitable simulator for adverse weather conditions
- failure to correctly follow the operating manual by the flight crew
- inadequate cockpit management (CRM)

The investigation released following findings:

1. During descent into Uromiyeh airport, the first stall warning (Stick Shaker) was caused by the inattentiveness of the pilot to the flap degrees. This problem was resolved by corrective action.

2. During descent into Uromiyeh airport, due to human error (both pilots), the aircraft did not acquire the correct ILS Inbound course and, because of this, the because of this, the flight crew made a Missed Approach decision.

3. After the missed approach at 16:00:41 UTC, despite a height of 8768 ft, pitch up 8.1, left bank angle 26 and speed 170 kt (within permissible operations), with Flap 5 the aircraft suffered a second stick shaker and lost height which is indicative of approaching stall speed.
Note: At this time, with flap 5 the maneuvering speed of this aircraft under normal conditions is 160 kt. It should be noted that this aircraft's speed was 170kt. Under normal conditions, the stick shaker speed is much lower than this.

4. The change in the aircraft's aerodynamic profile which is probably due to icing on parts of the fuselage that does not have Anti-ice system such as the tail section, cause the stall speed to increase so that the stick shaker was activated under these conditions.

5. Following the second stick shaker warning, for one second, the EPR for the three engines changed from (1.30 ? 1.25 ? 1.36) to (1.46 ? 1.48 ? 1.53) and after 4 seconds decreased to (1.05 ? 1.07 ? 1.06). This could be due to intake air turbulence caused by increase in the bank angle from 26 to 40 degrees left due to stall.

6. To get out of the stall, after 9 seconds at 16:00:50 UTC, the pilot orders maximum powers for all three engines. In this case, engine number 3 at 16:00:53 reached 2.14 EPR and subsequently at 16:00:55 due to entry of turbulent air entering the engine, the EPR parameter was reduced leading to the loss of the engine. After 5 seconds, the number 1 engine was lost in a similar manner.

7. With the occurrence of the second stick shaker, the pilot was forced to ask for increased powers for the engines. According to the FDR, the EPR parameter for the engines increased from (1.09 ? 1.36 ? 1.21) to (1.35 ? 2.06 ? 2.14) which is indicative of the crew's action to increase the engine power by quick movement of throttle (Rapid Acceleration). This action, taking into account the entry of turbulent air from the wings into engine intakes could result in engine flameout for engines 1 and 3.

8. At 16:01:07 the pilot ordered maximum power for all engines. Engine #2 complied with throttle movement and reached 2.11 which indicates this engine operated correctly until the accident.

9. Under the manufacturers training manual FCT 727, section ?Maneuver?, the pilot should have got the aircraft out of pitch and bank with the increased power to the engines. The pilot's action for bank was delayed.

10. Given the existing conditions, loss of two engines, existence of icing conditions, low speed (v=96kt) and low altitude (approximately 600 ft from ground), the crew's action to retract flaps was incorrect. This caused the aircraft to lose height faster although this act had no impact on preventing the accident.

11. The flight engineer, at the pilot?s command, began to restart the #1 engine but, due to the low altitude and lack of time, was unsuccessful.

The reader made The Aviation Herald aware of another important detail contained in the cockpit voice recorder transcript: According to the approach plate the lead in radial is 045 degrees (225 degrees), at which the turn to join the localizer should commence. According to the CVR the crew had set this to 070 degrees (250 degrees) instead which caused them to not be able to capture the localizer. The crew subsequently maintained heading 250.

The investigation reported the first officer (CPL, data not reliably determined) was pilot flying, the captain (ATPL, data not reliably determined) was pilot monitoring. The crew was assisted by a flight engineer.

The final report does not graphically present the flight data, however, narrates the FDR second by second later on (which could be copied and pasted in very large parts and thus could be translated with a sufficient level of certainty leading to the following narrative of the accident flight):

According to first translation attempts of the final report the aircraft carried sufficient fuel for the flight to Uromiyeh and back to Tehran (see flight plan below). The aircraft was descending through 13,400 feet MSL at 291 KIAS, engine EPRs were 1.05, 1.06 and 1.05, anti-ice systems had been turned on already on departure from Tehran, when approach control terminated radar services and handed the aircraft off to Uromiyeh Tower. The aircraft followed the TUBAR2A standard arrival to join the ILS/DME runway 21. The aircraft flew the 11 DME arc at about 10,200 feet, 224 KIAS and 4.1 degrees nose up. The engines, that had been accelerated in between reaching up to EPR 1.4, were reduced to idle again and stabilized at 1.05, 1.06 and 1.05 EPR, flaps 5 and further flaps 15 were subsequently selected, the aircraft slowed to 183 KIAS while still on the arc turning through 334 degrees at 9600 feet MSL. Descending through 7100 feet MSL at 171 KIAS and 4.6 degrees nose up, the crew stowed the speed brakes that had so far been in use. The speed decayed further, 22 seconds after descending through 7100 feet the aircraft descended through 7000 feet at 140 KIAS, still flaps 15, 11.6 degrees nose up and 17 degrees left bank. Turning onto finals through 298 degrees maintaining 7000 feet the speed decayed to 130 KIAS, 9 degrees left bank and 11.2 degrees nose up, the stick shaker activated (flaps 15 minimum speed 150 KIAS). The engines slightly accelerate to EPR 1.06, 1.10 and 1.06, the aircraft while still at 7000 feet turns through 288 degrees at 11 degrees left bank and 16.2 degrees nose up, speed further decayed to 120 KIAS. The flight engineer now applied full thrust, the engines spool up to EPR 2.14, 2.13 and 2.17, the aircraft descended through 6650 feet (MSA 7200 feet MSL) at 154 KIAS and 15 degrees nose up. The EGPWS announced 2500 feet. The aircraft reached a minimum altitude of 6644 feet MSL, then began to climb again. The aircraft climbed through 7000 feet at 154 KIAS and 9.9 degrees nose up, the engine thrust was reduced to EPR 1.75, 1.75 and 1.75, the aircraft levels off at 7064 feet, heading 199 degrees amd 156 KIAS, the crew decided to join the ILS. The crew attempted to engage the autopilot. The glideslope became alive with the localizer still off, the crew rejected the glide slope due to the localizer not yet being active. The aircraft climbed to 7200 feet, the glideslope indication went off scale again. The aircraft began to descend again, at 6900 feet the crew lowered the gear at 179 KIAS and a heading of 227 degrees. The engines get reduced to EPR 1.07, 1.08 and 1.10, heavy snow fall set in, the wind screen wipers were selected to maximum speed. The speed decayed to 139 KIAS again while the aircraft descended, flight engineer and captain called "SPEED", engines get accelerated to about 1.20, the EGPWS calls 2500 feet and "SINK RATE" (suggesting a sink rate of more than 2500 fpm). Descending through 6500 feet at 155 KIAS, the engines accelerate to EPR 1.40, 1.41, 1.40, the aircraft attitude is 7.5 degrees nose down and 213 degrees heading. At 5900 feet, 182 KIAS, 7.1 degrees nose up, +1.37G vertical acceleration, the crew announced the go around. The investigation annotated, that with the visibility of 800 meters and cloud ceiling at 1500 feet AGL (Uromiyeh elevation 4373 feet MSL) the crew never became visual with the aerodrome and never got inside the ILS cone. The aircraft climbed out, ATC instructed the aircraft to return to the IAF and join the hold at 9000 feet. The aircraft climbed through 6000 feet at 171 KIAS, The engine EPR reduced to 1.23, 1.21 and 1.26, the speed decays again to 153 KIAS at 13.3 degrees nose up. The engines accelerate again to 1.63, 1.70, 1.76 (where it should be above 2.00) while the aircraft is at 6277 feet at 5.9 degres nose up and 134 KIAS. The engine thrust increases further to 1.91, 1.98, 2.00, the aircraft is at 6200 feet, 142 KIAS, heading 196 degrees, 21 degrees left bank and 3.2 degrees nose up. At 6000 feet the engines reach 2.10, 2.06 and 2.09, heading 186 degrees, 3.2 degrees nose up, the speed increased to 155 KIAS. The aircraft continues to descend accelerating through 174 KIAS at 5900 feet, the flaps are selected to 5 degrees. At 5800 feet the speed is 187 KIAS, heading 165 degrees, left bank angle 27 degrees and 3.7 degrees nose up.

At 5800 feet and 191 KIAS the engines get reduced to 1.52, 1.47, 1.48, heading is 147 degrees, 22 degrees left bank, 5.5 nose up, the speed decays. The missed approach altitude gets set on the MCP, the VOR frequency is not set. The aircraft climbs through 6500 feet at 169 KIAS and a heading of 162 degrees, 10.3 degrees nose up. The crew discussed and set the VOR frequency, then focussed on the navigation towards the IAF. At the same time the aircraft stabilizes and continued to climb reaching 8800 feet at 181 KIAS and the engine EPR gets reduced to 1.32, 1.31, 1.38. The speed reduced to 174 KIAS, 6.9 degrees nose up.

At 16:00:27Z radar data and FDR indicate the aircraft is turning right, however, the FDR indicates the aircraft is in a left bank. The investigation annotates the facts leading to this strange situation, aircraft turning right in a left bank, are unknown. 6 seconds later the stick shaker activates, the aircraft is in a 21 degrees left bank but the heading shows the aircraft turning right. At 8700 feet the speed is 170 KIAS, engine EPR 1.36, 1.30, 1.25, 8.7 degrees nose up, 26 degrees left bank, the left bank increases to 41 degrees, the captain calls "Power! Power!", the aircraft heading suggests left turns again.

A few seconds later the aircraft is at 8700 feet at 168 KIAS, EPR 1.53, 1.46, 1.48, heading 344 degrees, 12.0 degrees nose up and 28 degrees left bank, the vertical acceleration increases to +1.2G when the engines sharply reduce to EPR 1.06, 1.05 and 1.07 within 2 seconds, the aircraft descends through 8500 feet at 155 KIAS at 334 degrees heading and 12.4 degrees nose up. The investigation annotates: it is possible that icing occurred at this time disrupting the smooth air flow over the wings. With the bank angle of 27 degrees left, 9.4 degrees nose up and the installation of the engines that turbulent airflow could have caused turbulence in the engine inlets causing the roll back of the engines.

The first officer commands the flight engineer to apply TOGA power, the captain calls "Power! Power!", the flight engineer confirms Go Around Power.

The investigation comments according to the FCOM: "Do not make rapid thrust changes in heavy precipitation (rain/hail) unless excessive airspeed variations occur. If thrust changes are necessary, move the thrust levers very slowly. Avoid changing thrust lever direction until engines have stabilized at a selected setting."

The thrust levers get increased, however engine #1 does not accelerate, EPRs are 1.27, 2.07, 2.03. The aircraft is at 8600 feet, 149 KIAS, 8.6 degrees nose and 39 degrees left bank. The aircraft descends through 8200 feet MSL, EPRs 1.21, 1.39 and 2.09, 148 KIAS, 278 degrees heading, 13.7 degrees nose up and 25 degrees left bank. Engine #3 also begins to run down.

The captain commands the engines to be firewalled. EPR 1.05, 2.11, 1.06, the aircraft descends through 7200 feet at 156 KIAS, 8.6 degrees nose up. Tower queries about their intentions.

The investigation annotates quoting the FCOM: "Flying in turbulence or hail may cause engine inlet airflow distortion. This distortion , along with engine icing , angle attack changes , and high altitude engine surge margins can result in engine surge and flame out."

Descending through 7000 feet the EPRs read 1.05, 2.10, 1.06, speed is 154 KIAS at 269 degrees heading.

The flight engineer observes engines #1 and #3 reducing their N1, EGT and oil pressure, the amber light for engines #1 and #3 illuminate, the engineer announced engine failure.

The first officer commands flaps up, speed is 152 KIAS, 6900 feet, 12 degrees nose up, 7 degrees left bank, the speed continues to decrease with the aircraft descending rapidly, 3 seconds later the airsped is 147 KIAS descending through 6700 feet at 14.1 degrees nose up.

The investigation reports at this time the sounds of an engine restart can be heard. The EGPWS announced 2500 feet, EPR 1.06, 2.04, 1.05, speed 141 KIAS, 6500 feet.

Descending through 6000 feet the captain radios Urumiyeh Tower advising they would return to Tehran. The first officer again commands the flaps up, the engineer is trying to relight engine #1. EGPWS announced "PULL UP!" EPR is 1.05, 2.10, 1.06, aircraft drops through 5700 feet at 13.3 degrees nose up. At 5000 feet the airspeed had dropped to 97 KIAS. The aircraft descends through 4400 feet at 112 KIAS, 6.8 degrees nose up and 21 degrees right bank. The last airspeed recording was 69 KIAS.

The aircraft was found crashed at coordinates N37.5528 E45.1656 at an elevation of 4,307 feet MSL, the aircraft broke up into four major sections upon impact with agricultural fields. 8 crew and 70 passengers died, one crew and 26 passengers survived with serious injuries. The aircraft was destroyed.

Both flight data recorders were recovered with damages, needed to be cut out of the aircraft using hydraulic tools and were delivered to the investigation.

On Nov 13th 2017 Iran's Civil Aviation Organisation CAO, having taken note of our plea for assistance with the Persian final report, sent The Aviation Herald an e-mail summarizing the final report as follows:

About B727, EP-IRP we know that:

1- the crew could not align the aircraft in ILS inbound course due to setting wrong understanding of lead Radial for approach.

2- the pilot decided to Miss Approach and getting back to IAF but while 25 Deg banking with flap 5, they encountered Stick shaker which means near to stall.

3- the weather was in icy condition. The pilot should use enough power to supply hot air from engines for Anti-icing. This action was not observed by them. This error caused accumulation of Ice (snow) on wing surface and Engine nacelle.

4- they decided to increase power of the engines with rapid acceleration after stick shaker to get high velocity to prevent stall.

5- the crew tried to restart the Engine #1 but it was too late and aircraft impacted with ground.

6- due to Ice accumulation ON WING SURFACE, there was turbulence airflow in the engine intakes . so engine #1 and 3 were flame out and EPR decreased.

The causes of the accident are stated as:

1- severe icing condition for the flight and lack of enough preparation for cockpit crew to face this weather phenomenon.

Metars:
OITR 091800Z 29004KT 0500 +SN SCT015 SCT020 OVC060 00/00 Q1016
OITR 091750Z 29004KT 0500 +SN SCT015 SCT020 OVC060 00/00 Q1016
OITR 091700Z 33004KT 0600 +SN SCT015 SCT020 OVC060 00/00 Q1016
OITR 091650Z 33004KT 0600 +SN SCT015 SCT020 OVC060 00/00 Q1016
OITR 091600Z 26004KT 0800 SN SCT015 SCT020 OVC060 00/00 Q1016
OITR 091550Z 26004KT 0800 SN SCT015 SCT020 OVC060 00/00 Q1016
OITR 091500Z 24006KT 0800 +SN SCT015 SCT020 OVC060 00/00 Q1015
Incident Facts

Date of incident
Jan 9, 2011

Classification
Crash

Airline
Iran Air

Flight number
IR-277

Departure
Tehran Mehrabad, Iran

Destination
Uromiyeh, Iran

Aircraft Registration
EP-IRP

Aircraft Type
Boeing 727-200

ICAO Type Designator
B722

Airport
Urmia Airport, Urmia

Airport ICAO Code
OITR

This article is published under license from Avherald.com. © of text by Avherald.com.
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