Alitalia A320 at Rome on Sep 29th 2013, right main gear did not extend due to debris in hydraulic gear door actuator

Last Update: September 29, 2016 / 16:28:12 GMT/Zulu time

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Incident Facts

Date of incident
Sep 29, 2013

Classification
Accident

Airline
Alitalia

Flight number
AZ-63

Departure
Madrid, Spain

Aircraft Registration
EI-EIB

Aircraft Type
Airbus A320

ICAO Type Designator
A320

Airport ICAO Code
LIRF

An Alitalia Airbus A320-200, registration EI-EIB performing flight AZ-63 from Madrid,SP (Spain) to Rome Fiumicino (Italy) with 151 passengers and 6 crew, was on approach to Rome's runway 16L at about 20:10L (18:10Z) when the crew needed to go around due to one of the main gear struts indicating unsafe. The crew worked the relevant checklists without resolving the issue and therefore performed a low approach to runway 16L tracking between runway and parallel taxiway to have the aircraft inspected from the ground. The crew subsequently prepared for an emergency landing with the right hand main gear remaining retracted due to the right main gear doors not opening. The aircraft landed on runway 16L about 50 minutes after aborting the first approach and 25 minutes after the low approach, the aircraft came to a stop on the runway. The aircraft was evacuated via slides. There were no injuries.

Italy's ANSV have opened an investigation into the accident. On Sep 30th the ANSV announced that two investigators have been dispatched on site to examine the aircraft and collect evidence. All occupants remained unharmed.

On Oct 1st 2013 the BEA reported the aircraft scraped the right hand engine on the runway since touch down after the crew could not extend and lock the right hand main gear. The occurrence is rated an accident and being investigated by the ANSV.

Another A320 had suffered a similiar fate in Rome recently, see Accident: Wizz A320 at Rome on Jun 8th 2013, left main gear did not extend.

On Dec 4th 2013 the ANSV released safety recommendations to EASA stating that current required checks are not effective to detect a developing failure of the main gear door actuators. Instead a campaign to replace current actuators with an improved version, that no longer requires such tests, should be accelerated. In addition, the ANSV recommends to require maintenance inspect and clear the associated hydraulic system in case of faulty door actuator being found.

The ANSV argues, that debris had been found within the failed and not failed gear door actuators of all three aircraft, EI-EIB, Wizzair's HA-LWM and N816UA, see Accident: United Airlines A319 at Newark on Jan 10th 2010, right main gear did not deploy. While maintenance procedures and airworthiness directives required the replacement of the actuator, neither required the associated hydraulic system to be inspected.

The ANSV reported, that the crew worked the checklists after receiving indication, that the right main gear was not locked into its extended position, amongst te procedures were high G procedures (+1.75G according to flight data recorder) with gear lever down, alternate gear extension, however all measures did not manage to extend the gear leg. The crew subsequently prepared for an emergency partial gear up landing at Fiumicino Airport, just before touchdown both engines were shut down, the right hand engine scraped along the runway until the aircraft came to a stop.

The ANSV stated: "The investigators noticed the right MLG door actuator only partially extended and the right MLG not in the up-lock position, but stuck on the door (the door was not touching the terrain and no signs of ground contacts were present on it – picture 2). At removal of the jammed actuator, the door fully opened and the gear correctly extended and locked."

Heavy debris was found in the damping housing of the failed actuator, some dampening components were missing with the exception of the retaining ring which however was out its design position. Tests confirmed the actuator was really jammed. Only when 1000psi hydraulic pressure were applied the failed actuator could be extended to near its extended length.

The left hand main gear actuator was also found containing debris, however, it was functional with a slight anomaly on the dampening speed (faster than maximum speed allowed).

The flight data recorder confirmed that after selecting the gear down the crew waited for more than 2 minutes before attempting the free fall procedure as recommended by the operations hand book.

The ANSV stated: "Recurrence of the accident, that seems fully coherent with the previous two events, one occurred at Newark Liberty International airport (NJ, USA) on January 10th 2010 to the A319 aircraft registration marks N816UA (equipped with a MLG door actuator std-10), and the other one occurred at Fiumicino airport on last June 8th 2013 to the A320 aircraft registration marks HA-LWM (equipped with a MLG door actuator std-12, like the one installed on the subject event), poses serious concerns about the effectiveness of the mitigation actions currently in place while taking into account the large fleet potentially affected by the issue. The DFDR analysis demonstrated that the total opening time of the main landing gear doors in the last two accident flight took about 4.5 seconds. So even if for the Wizzair case it has been individuated a problem solved with the Emergency AD 2013-132-E about the aircraft for which the interlink communication ARINC 429 was installed, the warning message on the PFR should have been not found. Further analysis have been performed on the DFDR data coming from the database of the ANSV Laboratory (A320 family fleet data), and normally the total timing for the main landing gear doors opening has been found between 3.5s to 5s (accident flight included)."

The ANSV voiced concern with the timing of a solution: "The recent introduction of the P/N 114122-014 as indicated by the SB 32-1407 released in May 2013, and by the OIT 999.0074/13 issued on October 30th 2013, that it is intended to fix the problem through a new design of the internal damping mechanism, if effective, could still require too long a time to ensure the highest safety standard before completion of the retrofit of the fleet."

On Sep 29th 2016 Italy's ANSV released their final report in Italian concluding the probable cause of the accident was:

The cause of the event is attributed to damage the right hand main gear door actuator had received.

There was a hydraulic blockage found inside the actuator caused by multiple pieces of debris in the restricted area as well as hydraulic fluid.

The pieces of debris originated from the "Spirolox Ring" and "Damping Ring" found missing from their housings.

This failure seems to be attributed to a design flaw in the Spirolox Ring, the effects of which cause early deterioration and failure of the ring, which is consistent with the damage found within the actuator.

The ANSV reported that there was contamination in the left hand gear door actuator, too, which however did not (yet) block however had lost most of its damping properties as result of the contamination. Both left and right hand main gear door actuators had been installed on the aircraft since new.

The ANSV analysed that there were no errors committed by the flight crew, the procedures were followed by the book. In particular the gravity extension procedure, which required to re-cycle the landing gear lever, then wait for at least 2 minutes with the gear lever in the DOWN position before activating the gravity extension procedure has been followed by the crew, who waited for 2:15 minutes.

The ANSV analysed that the examination techniques to detect possible contamination were insufficient to detect deterioration of the actuators in time, and therefore recommended to introduce x-ray checks to the checks of the gear door actuators.

The ANSV also stated in their safety recommendations released with the final report, that no procedures existed to take care of a hydraulic system, which was driving a failed actuator. The procedures just required the replacement of the failed actuator, however, did not require cleaning of the hydraulic system. The ANSV thus wrote to EASA: "ANSV strongly recommends to ask for the proper technical actions to be carried out on the hydraulic system of the landing gear doors to be sure that contamination is not present in case of a landing gear door actuator removal." Two more recommendations were made.

Related NOTAMs:
A6444/13 - RWY 16L/34R CLOSED TO ALL TRAFFIC DUE TO CRASH ACCIDENT. REF AIP AD 2 LIRF 2-1. 29 SEP 19:30 2013 UNTIL 30 SEP 10:00 2013 ESTIMATED. CREATED: 29 SEP 19:30 2013

Metars:
LIRF 292020Z 22009KT 170V230 9000 TS FEW013CB SCT027 23/20 Q1006 RERA NOSIG
LIRF 291950Z 17011KT 8000 -TSRA FEW013CB FEW015 SCT027 22/21 Q1005 NOSIG
LIRF 291920Z 15008KT 110V200 8000 -TSRA FEW013CB SCT024 FEW015 23/22 Q1006 NOSIG
LIRF 291850Z 17007KT 8000 FEW015 SCT024 23/22 Q1006 TEMPO 3000 TSRA SCT020CB
LIRF 291650Z 16010KT 9999 -DZ FEW012 BKN024 24/22 Q1007 NOSIG
LIRF 291620Z 16011KT 9999 FEW012 SCT024 23/21 Q1007 NOSIG
LIRF 291550Z 16014KT 9999 FEW015 SCT024 24/21 Q1006 NOSIG
LIRF 291520Z 17014KT 140V200 9999 FEW015 SCT021 25/21 Q1007 NOSIG
Aircraft Registration Data
Registration mark
EI-EIB
Country of Registration
Ireland
Date of Registration
Manufacturer
AIRBUS INDUSTRIE
Aircraft Model / Type
A320-216
ICAO Aircraft Type
A320
Year of Manufacture
Serial Number
Aircraft Address / Mode S Code (HEX)
Maximum Take off Mass (MTOM) [kg]
Engine Count
Engine
HnjcqmmA enmb g Subscribe to unlock
Main Owner
NcmqdpgfqlqipbkAeckgml fdnmpjfejcAqggd hfeeknjg m b fAehAgpldjkcAddgpbeqphjnlAffh lpngAc Subscribe to unlock
Incident Facts

Date of incident
Sep 29, 2013

Classification
Accident

Airline
Alitalia

Flight number
AZ-63

Departure
Madrid, Spain

Aircraft Registration
EI-EIB

Aircraft Type
Airbus A320

ICAO Type Designator
A320

Airport ICAO Code
LIRF

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