[Accident Report] 11/07/2017 SAS CRJ-900 (reg EI-FPG) on flight SK-589 Stockholm-Brussels

[Passenger]

Qualification "Accident report" on AvHerald:

"...On 11th July 2017, a SAS CRJ-900 (reg EI-FPG) performing flight SK-589 from Stockholm to Brussels, was enroute when the crew was informed about tyre debris having been found on the departure runway. The crew elected to continue the flight to Brussels and requested emergency services on stand by for the precautionary landing... The aircraft landed safely on BRU runway 25L about 2 hours after departure. Emergency services reported the #2 tyre (inboard left main) was blown. A post flight inspection revealed damage to the flaps and foreign object ingestion into an engine... The aircraft was unable to depart for the return flight and is still on the ground 132 hours after landing..."

http://avherald.com/h?article=4abb67af&opt=0

[luchtzak]

Via social media somebody asked why the crew continued to Brussels iso returning to Stockholm ...

[CTBke]

maybe it's in the WX procedures ?

[Passenger]

Me thinks that a notice "tyre debris has been found on the runway" should lead to a return and/or a precaution landing. Such notice means it's not just a flat tyre.

[sn26567]

If the plane was still in BRU 132 hr after landing, the repair (and the incident) must be serious. Is it still in BRU now?

[sn26567]

Looking at FR24 data, I see that EI-FPG on 11 July made a short flight (SK5890) around ARN airport (at the STD to BRU) before really taking off to BRU. Did the incident occur on this short flight, or on the (late) departure to BRU as SK589?

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[Homo Aeroportus]

Looking at FR24 data, I see that EI-FPG on 11 July made a short flight (SK5890) around ARN airport (at the STD to BRU) before really taking off to BRU. Did the incident occur on this short flight, or on the (late) departure to BRU as SK589?

Capture.PNG

I guess that EI-FPG went through Mx during the night and had a dry run in the morning before operating the SK589 which indeed took off 90 minutes late.
Would be interesting to know what Mx was performed at SAS and what takes so long in BRU to bring her back in service.

H.A.

[flightlover]

Looking at FR24 data, I see that EI-FPG on 11 July made a short flight (SK5890) around ARN airport (at the STD to BRU) before really taking off to BRU. Did the incident occur on this short flight, or on the (late) departure to BRU as SK589?

Capture.PNG

I guess that EI-FPG went through Mx during the night and had a dry run in the morning before operating the SK589 which indeed took off 90 minutes late.
Would be interesting to know what Mx was performed at SAS and what takes so long in BRU to bring her back in service.

H.A.

Maybe the bursting tyre has hit some non 'off the shelf' parts that need to be replaced. And maybe they need some specialized tools and mechanics to be flown over to replace them. BRU is not really known to be a maintenance base for CRJ's.

[Hue]

The aircraft landed on runway 25L in Brussels to protect 25R for departures + arrivals in case of damage to the pavement or a blocked runway. Emergency services were available upon landing and immediately checked the tires. Thorough inspection confirmed no damage to the runway or taxiways.
The works on runway 25L late August are not related to this arrival.

[pilot_gent]

Me thinks that a notice "tyre debris has been found on the runway" should lead to a return and/or a precaution landing. Such notice means it's not just a flat tyre.

They asked for emergency services on standby = at least precautionary.

Regarding a return: with no evidence of other damage you are looking for a long runway and low weight (read = not a lot of fuel). As BRU has a long runway, it was probably decided in cooperation with the company to continue. Normal decision imo.

[epsilon]

The Boeing training manual even recommends to continue to destination after a tire burst(if no other obvious damage that would need a return). More time to think enroute and lower landing weight at destination means less braking.

[Bralo20]

The Boeing training manual even recommends to continue to destination after a tire burst(if no other obvious damage that would need a return). More time to think enroute and lower landing weight at destination means less braking.

The difference with virtually any Boeing (except for the MD8x/9x and the B717's) is that the chances of FOD in the engines is relatively slim compared to the CRJ's due to the position of the MLG compared to the engines. With a B737,747,757,767,777,787 there's virtually no possibility that tire debris will be ingested in the engines (except when one of the NLG tires explodes of course). But with the CRJ (and certain other planes) the engines are hanging in the path that debris will take when a wheel explodes, specially during take-off.

So IMHO the risk in a CRJ is quite a bit higher compared to virtually any Boeing and any Airbus plane. On the other hand, landing an overweight plane with one of more damaged tires has his risks also. In the end it's a bit of a gamble following the assessment of the flight crew, if they don't see anything suspicious on the flight deck and nobody hears strange noises coming from the engines then you might assume they could be ok without (severe) damage. But minor damage can eventually grow into bigger damage and a sudden break without any indications on the flight deck. So, in the end it's a bit of a gamble, even after thorough risk assessment on board. Nothing happend this time but an uncontained engine failure was one of the possibilities in this case. Ultimately it's the captain who makes the decision to continue or to return and will take responsibility for it.

[RTM]

The way I read the article, It took off uneventfull, but was notified enroute that tire debris was found on the runway. No certainty that it came of this A/C, but since it was one of the candidates, they were notified. No abnormal readings on the engines, continue flight. Upon arrival in BRU, they asked for emergency services to stand by because of the notification they got. During landing, the tire completely gave out, causing damage to the flap and engine. Safe landing, but A/C AOG.

Just my 2 cents.

And btw, the A/C is still in BRU, inside H41 for repairs.

[Bracebrace]

So IMHO the risk in a CRJ is quite a bit higher compared to virtually any Boeing and any Airbus plane.

Engine damage is "a" risk. There are plenty of other risks.

Direct problems:
Boeing have more complex flap designs, flap damage might be bigger but more apparent (blocked flaps)
Boeing have pitot tubes on the tailplane used by the flight controls for force feedback.
Indirect problems:
Retracting a damaged main gear tire on a 737 can lead to a lot of other problems as a lot of systems pass through the landing gear bay (unfamiliar with the CRJ, don't know what hides in their landing gear bay). It is better to leave the gear out for a certain time.

Only to say that the "risk to continue" on a CRJ is "higher" only because of engine location is a very focused viewpoint.

Pilots start with facts and if instruments and data show no issues, you can continue. CRJ or Boeing, the pilots will work in the same fashion.

[RTM]

Retracting a damaged main gear tire on a 737 can lead to a lot of other problems as a lot of systems pass through the landing gear bay (unfamiliar with the CRJ, don't know what hides in their landing gear bay). It is better to leave the gear out for a certain time.

Don't know either aircraft very well, but it is more or less the same, the gear bays are ideal locations to put systems in. I do know that on the CRJ however, there is protection because the wheels retract into a shielding tub inside the well, so that should help. But also, almost all modern aircraft have retaction braking, meaning that as soon as the gear is selected up, the wheels stop spinning to get rid of gyroscopic effects. So that would eliminate the need to leave it down for a certain time.

[epsilon]

The 737 has a very smart system, if you have tire damage and the spinning thread impacts a fitting on the wheelwell it will automatically freefall back down and locked preventing retraction and wheelwell damage.

[Bracebrace]

The NG has the freefall down functionality, not the classic.

So that would eliminate the need to leave it down for a certain time.

The freefall down system on the NG shows there is a danger on the classic. There is also the much more present fire danger (ie hydraulic line rupture on the landing gear and hydraulic liquids hitting hot wheel systems)

[RTM]

Tire bursts generally happen with gear extended. And the design should be that it can absorb an impact without causing too much failure. But you never know. But retraction braking should prevent pieces of rubber flinging into other area's during or after retraction. But as stated, I am not familiar with nor the 737, nor the CRJ. Though lots of experience with other Bombardier products, and this seems to be their philosophy.
As for hydraulic fluid causing fires... no. Phosphate ester based hydraulic fluids, as used on all modern, larger aircraft, is fire resistant. Mineral based MIL-H-5606 is another story, but not much airliners still use that...

[Bracebrace]

Phosphate ester based hydraulic fluids, as used on all modern, larger aircraft, is fire resistant.

Wasn't aware of this, you will see the note appear in many pilot notes though. Thanks.

[RTM]

In all honesty... fire resistant is not the same as fireproof. Under the right circumstances it can ignite, but will not sustain a fire. Also, as fluid gets older, and more contaminants settle into it, flamability caractiristics change. So, from a pilots point of view, and thus their procedures, eliminating as much risk as possible makes perfect sense.