Iceland Connect DH8D at Reykjavik on Aug 9th 2018, engine shut down in flight
Last Update: January 7, 2020 / 18:41:31 GMT/Zulu time
The airline reported soon after takeoff the right hand engine failed and was shut down. The aircraft returned safely.
A replacement Dash 8-400 registration TF-FXB reached Egilsstadir as flight NY-1336 with a delay of 2 hours.
In 2019 Iceland's RNSA released their final report in Icelandic only (Editorial note: to serve the purpose of global prevention of the repeat of causes leading to an occurrence an additional timely release of all occurrence reports in the only world spanning aviation language English would be necessary, a Icelandic only release does not achieve this purpose as set by ICAO annex 13 and just forces many aviators to waste much more time and effort each in trying to understand the circumstances leading to the occurrence. Aviators operating internationally are required to read/speak English besides their local language, investigators need to be able to read/write/speak English to communicate with their counterparts all around the globe).
Editorial note: It is impossible to make any meaningful and reliable translation out of this report. Hence in the following only a few clearly identifyable key facts are mentioned.
The right hand engine needed to be shut down due to the loss of oil pressure. After landing a large puddle of oil developed below the right hand engine. The oil leak was caused by a retaining ring at the oil nozzle of the starter drive access cover, which separated causing both the retaining ring and the oil nozzle to be found loose in the engine nacelle. Prior to the flight there had been inspection works, during which a maintenance engineer in training incorrectly placed the oil nozzle. Due to holidays, illnesses and another aircraft taking the attention no licensed aircraft maintenance engineer had time to supervise the work.
On Dec 27th 2019 the RNSA responded to an inquiry by The Aviation Herald, whether an English version of the final report would be or become available for the benefit of aviators all over the world, who would all struggle for hours to understand the Icelandic report while it would be a matter of a few hours only for the Icelandic investigators to produce an English translation:
As an Icelandic government institution, the Icelandic Transportation Safety Board (ITSB) is in general required to submit its material in Icelandic. An exception to this is per article 32 of Icelandic law 18/2013, where the ITSB is allowed to issue its reports in foreign language, for example in cases where person involved is foreign. Therefore, as an example if a foreign pilot, foreign mechanic, foreign manufacturer, foreign authority, etc are involved in the accident or the accident investigation, the general rule is that the ITSB (in the case of aviation accident or serious incident) will write the report in English.
In this particular investigation, all parties involved were Icelandic. No input was required from the airplane manufacturer, EASA or other foreign parties in the investigation and all safety recommendations in the report are issued to Icelandic parties. Therefore the report was written in Icelandic.
On Jan 7th 2020 The Aviation Herald released an English summary produced by an Icelandic reader, who provided assistance to The Aviation Herald to create a meaningful summary of the final report. The final report concludes:
RNSA believes that the main reason for the incident was the shortage of licensed and experienced mechanics on the day of the incident.
RNSA also believes that it was a contributing factor that mechanics and managers in the maintenance department didn’t follow procedures that they should have followed.
Four mechanics were involved in the occurrence:
Licenses: Sveinspróf [Translation note: Proof that he finished his education as a mechanic], Part-66 license with the types Bombardier DHC 8-100/200/300, Bombardier DHC 8-400, Fokker 50/60
Experience: Finished his theoretical test 2002, 12 years at this air operator [Air Iceland Connect]
Experience: Finished his theoretical test in June 2014, 15 months at another air operator, 27 months at this air operator, has the preconditions to apply for a Part-66 license but didn’t do so yet, theoretical test for Bombardier DHC 8-400
Licenses: Flight mechanic student (EASA Part 147 Certificate of recognition for B1)
Experience: Finished his theoretical test in June 2014, 14 months at this air operator
Licenses: Sveinspróf, Part-66 license with the types Bombardier DHC 8-100/200/300, Bombardier DHC 8-400, Fokker 50/60
Experience: Finished his theoretical test in 1999, 19 years at this flight operator
The RNSA described the sequence of events:
The pilots of the Bomardier DHC-8-402 aircraft with the registration TF-FXA declared an emergency at 15:07, two minutes after takeoff from RWY 31 at Reykjavík Airport (BIRK).
The aircraft has lost oil pressure on the right hand engine, the pilots shut down the engine and came back for landing with the other engine working for an otherwise uneventful landing.
After landing a big oil leak was found in the right hand engine. The retaining ring that is supposed to hold the oil nozzle of the starter drive access cover of the engine has loosened, both parts were laying in the engine nacelle.
The investigation showed that maintenance work has been performed prior to takeoff where an inspection of the engine interior with a borescope has taken place. The day before, mechanics opened both engines for the inspections as described in the aircraft manual.
A special borescope inspector then inspected the left engine. He asked to open the engine further, which was performed by the operator’s mechanics.
On the evening before the incident, after the borescope inspector had finished his work, the left engine was closed again. The inspector postponed the inspection of the right hand engine [the incident engine] to the morning of the incident.
The operator had their maintenance structured into 6 shifts with 3 mechanics each, 18 mechanics in total. Four of these 3 man shifts were distributed to be on site 24/7 in a so-called 5-5-4 shift system. Two teams of 3 mechanics were so called Scheduled Maintenance evening shifts between 18:00 and 02:00.
Because of that, there were up to 9 mechanics at a time on site, both licensed mechanics and students. The operator’s organization was set up in a way that the planes are mainly flown during the day so that during the evening hours / in the night maintenance takes place. Cand D-checks are performed abroad, i.a. Because the Q400 planes were rather new in the operator’s fleet.
When sickness, summer vacations and other cases of absence came up, a shift was in general not reassigned to someone else. Additionally, employees were taken off their scheduled shifts to cover urgent open positions in the operator’s workshops due to summer vacations.
Thus, on the day, three mechanics were on line maintenance. Because of summer vacations, two mechanics were put onto the line maintenance on the day of the incident.
The first of them, mechanic A, who was also supervisor in line maintenance, had a type rating for Bombardier DHC-8-400 aircraft.
The second one, mechanic B, had finished his sveinspróf and thus had the right to apply for a Part-66 license, but did not do it. He finished the theoretical training for his first type rating (Q400) but still had his practical training ahead.
Earlier in the morning, another aircraft of the operator had a problem in Egilsstaðir (BIEG), so that the line maintenance mechanic with type rating, mechanic A, was sent there to work on this aircraft. When the time came to close the right hand engine of the incident aircraft, mechanic B was the only line mechanic left to work on it, but mechanic D was also in the building working on something different.
It was not planned to bring another mechanic with a type rating into the project [of closing the engine] when mechanic A left Reykjavík. Because of that, a mechanic with type rating was missing to supervise the borescope inspection on the right hand engine, i.e. as nominated person (according to Part-66 III 6) On the job training) for mechanic B.
First, the borescope inspection for both engines of TF-FXA was scheduled for August 8th (day prior to the incident), where 5 mechanics with type rating have been scheduled on a shift.
The inspection was delayed because the aircraft was [likely: unplanned] used for a flight on the morning of August 8th.
That was the reason that the borescope inspector could only finish the left hand engine inspection on the evening of August 8th, the inspection of the right hand engine was postponed until the following morning.
TF-FXA was not scheduled to fly on the day of the incident, but because of the breakdown of the airplane in Egilsstaðir and because of the necessity of an additional flight to Greenland, operation management and the maintenance supervisor decided to expedite the maintenance on TF-FXA. Subsequently the plane was planned in on a flight later that day. This decision was not followed by a plan to change the staffing.
Because of the additional work, mechanic B realized he was under time pressure and asked for assistance. He got the assistance of two maintenance students who were scheduled as replacement for employees in summer vacations in the oxygen workshop and in the storage. Those students have not been part of the opening of both and closing of one engine the evening before.
Another mechanic, mechanic C, put the oil nozzle onto into the right engine and put on the retaining ring. He had the aircraft manual next to him for guidance. The mechanic was employed for 14 months at the operator. He had neither a Part-66 license nor a finished type rating for the Q400. He was thus working under supervision of an employee with type rating.
One mechanic with type rating (mechanic D) was in the building, but he came to work at 8 in the morning. He worked as a replacement for a staff member in summer vacations in the electricity workshop of the operator. He replaced there a man in summer vacations who would else run this workshop, a total of four people at the operator had such a license.
According to mechanic D the nature of the work in the electricity workshop was that he would otherwise be there and didn’t have much time, he also simultaneously helped mechanic A over the phone with looking things up in the manual and with trouble shooting for the plane in Egilsstaðir. It was very difficult for him to also work as a supervisor for the closing of the engine of TF-FXA and to certify this work but he let the pressure of his boss make him also take on this work in the afternoon.
When mechanic D first came to work on the engine (which was in the afternoon), all that needed to be done was done, the mechanic student C held onto the oil nozzle. Before he noticed student C put the oil nozzle on, he needed to go back to his work to the electrical workshop.
When mechanic student C worked on closing the right engine, he had quite some problems with finishing it because of tight access to this part of the engine. There’s no direct access to the valve because it’s behind the engine. It was for example necessary to remove a duct to be able to use the tools for opening and closing the engine. The fastening ring that was set behind the oil nozzle is tensed while putting it in and then expands into a groove in the valve when the tension is released. Mechanic student C worked on his work without being under competent supervision of someone with a type rating.
When mechanic D came again to the engine, the whole oil system of the right engine was closed as well as all the things that had to be removed to access the valve had been put into place again. He went loosely over all the closing work but thought that he went over it more extensively. He did not recall inspecting the valve related parts in particular and the work that has been done there.
The aircraft was then taken out of the hangar and did a runup according to the instructions in the aircraft maintenance manual and then the engine was shut down. No leak was found during the runup. The aircraft was signed out of maintenance at 14:20 by mechanic D.
The RNSA analysed:
RNSA thinks that the oil nozzle has not been placed correctly enough into the valve, because you need to hit onto it a bit so that it goes all the way in. The groove where the ring was supposed to go into was likely covered by the oil nozzle with the result that the ring couldn’t go all the way in and couldn’t loosen the tension in the groove where it was supposed to be.
When the oil pressure increased during takeoff, the oil nozzle was slowly pushed out because the ring didn’t hold it in place. Finally, it totally fell off into the nacelle and the right hand engine lost oil pressure.
During the investigation it became clear that neither mechanic B, who was alone with closing the engine after the inspection, nor mechanic student C who came to help out had a Part-66 license.
Mechanic B had the right to apply for a license but didn’t do so and thus was un-authorized staff. Therefore he was working under the supervision of someone with a Q400 type rating who had the right to vouch for mechanical work.
In the case of mechanic student C, he was still working on the practical part of his mechanics license. His work in line maintenance was as well under the supervision of someone with a type-rating for the Q400.
The investigation showed that the work of mechanic B and mechanic student C was insufficient for two reasons:
- No type-rated mechanic was assigned to supervise the work after mechanic A left Reykjavík.
- When mechanic D was assigned to supervise the work, he wasn’t able to do it because he was occupied with other work (working in the electronic workshop and assisting mechanic A over the phone)
The investigation showed that finishing the task card was insufficient:
- Mechanic A signed off the boroscopic inspection in the morning before he left Reykjavík
- Mechanic A was supposed to sign off closing the engine after the inspection later that day. He was not on site though when the engine was closed since he left Reykjavík earlier and wouldn’t come back until after TF-FXA was released from maintenance.
- Mechanic B on line maintenance was the one who signed off the work on the task card. He didn’t have the license to sign this task card off though, so that the person supervising him should’ve signed it off.
- The task card for closing the engine was especially marked as a critical task. This meant that an independent inspection should’ve taken place of the work performed on this task card. This meant that an independent qualified person who did not work himself on the engine had to inspect it and sign it off. Mechanic D was the person who signed this independent inspection and he was also the one who supervised the work and signed it off.
- Mechanic D could not be at the same time the one signing the work of mechanic B that he supervised off and independently inspecting this work. He should have demanded that someone else from the maintenance team who was authorized staff did this.
- It was not planned to change staffing when the schedule got delayed the day before
- Nowhere in the papers of the operators it became evident that mechanic student C actually performed the tasks to close the valve of the right engine.
Maintenance takes place in a certified environment according to EASA Part-145. It is the responsibility of the accountable manager and maintenance manager to ensure that work happens according to Part-145 and the confirmed maintenance manual that the work is done after.
RNSA believes that the mechanics and managers in the maintenance department have let the pressure to release the plane into operation made them to not follow the procedures that they’re required to follow. From a safety point of view, RNSA believes that the maintenance manager should have been decisive about which tasks are performed, which can wait and whether to call in additional staff on the day of the incident.
Regarding the independent inspection of the closing of the right engine: There should have been at least two authorized staff members on site and one of them with the right to sign off maintenance. After mechanic A left Reykjavík there was only one such staff member on site (mechanic D).
Flight operations could decide to not let the plane go the scheduled maintenance on the day before the incident without approval from maintenance.
Samgöngustofa [Icelandic CAA] gave out a manual of twelve human factors related problems that can lead to accidents and multiple of those were found in this case.
The shift system at the operator was changed after this incident. Now there are two supervisors that have the overview over everything that’s going on, one during the day and one during evenings. They are assisted by two line maintenance persons in a shift system and fixed day- and evening persons. During the day there are 4-5 and during evenings 5-6 people always on site, this is dependent on the time of the year.
In the operator’s maintenance manual it’s now described how practical training after the theoretical type rating training should be done. “Training mechanics” have been appointed who take over practical training new mechanic students.
This article is published under license from Avherald.com. © of text by Avherald.com.
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