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air safety

Apr 27, 2017

Singapore Airlines cleared over Melbourne 777 tail strike incident

That much reported tail strike incident involving a SingaporeAir jet at MEL turns out to have been a case of exemplary piloting when things didn't go as planned

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The tail skid protection device on a -300 sized Boeing 777

The actions of Singapore Airlines pilots in continuing to fly to Singapore in a Boeing 777 after a confirmed tail strike on takeoff from Melbourne Airport last October have been exonerated and praised by an ATSB inquiry.

The ATSB found that the pilots had correctly determined that the aircraft’s pressurisation system had not been affected, and that they had continued the flight safely and in accordance with Boeing’s recommended action for dealing with such incidents.

The report is an interesting sequel to various tabloid media reports at the time insinuating that the pilot actions were unsafe or risky, and that they should have turned back immediately once Melbourne Airport confirmed that a tail strike protection device had left evidence of it being scraped along part of the runway.

The incident, on October 9 last year, occurred during wild weather with high gusty winds at Melbourne Airport. During the pre-flight external inspection of the 777-300 one of the pilots noted that “it was difficult to walk straight due to the wind.”

While taxying to their holding point for takeoff from runway 34 they saw two aircraft go around after abandoning approaches to the same runway.

The ATSB found that winds had been gusting to a maximum of 45 kt, and turbulence had been reported in the control zone.

During the take-off run, as rotation was initiated, the headwind component decreased resulting in the aircraft’s airspeed reducing below rotation speed. This airspeed reduction prolonged the time to lift-off, allowing the pitch attitude to exceed the tail skid contact attitude.

After take-off, air traffic control contacted the flight crew alerting them of a ‘possible tail strike’. With no TAIL STRIKE caution message displayed on the engine indication and crew alerting system the flight crew carried out the unannunciated tail strike non-normal checklist and determined the aircraft structural integrity was intact.

An inspection of the runway identified contact marks, consistent with a tail skid contact. Air traffic control advised the flight crew that ‘only superficial concrete debris were found’ during the runway inspection.

The flight crew discussed all the available information and considered their options. With the aircraft pressurisation system indicating no abnormalities the captain made the decision to continue to the destination. The remainder of the flight was uneventful. On arrival in Singapore engineers conducted a post-incident inspection of the aircraft. Damage was evident to the tail skid system indicating that a moderate energy skid contact had occurred during take-off.

The pilots used a reduced thrust  engine setting for takeoff, as most jet airliners do when using suitably long runways. This saves fuel and engine wear.

The ATSB notes that had the pilots on this occasion used a higher thrust setting it would most likely have minimised the exposure of the 777 to the gusty wind conditions during rotation and liftoff.

The tail skid protection system contact with the runway was caused by airspeed stagnation at the critical moment. The pitch attitude of the 777 when it lifted off was 10.7 degrees nose up, exceeding the 8.9 degrees where a 777-300 will have a tail strike.

The report says that Singapore Airlines has since drawn pilot attention to Boeing’s recommendation to use a higher thrust and rotation speed during gusty and strong crosswind conditions.

However it concludes by saying that the Singaporean crew provided an excellent example of how to manage a non-normal situation and through good communication and decision making processes, were able to complete the flight without compromising safety.

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29 comments

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29 thoughts on “Singapore Airlines cleared over Melbourne 777 tail strike incident

  1. 777 Steve

    Ben, I can’t remember if at the time what was said, but the Boeing recommendation is exactly as was followed by the Singapore crew. It differs significantly from the -200 variant of the 777 primarily because no tailskid is fitted. On the larger question of airmanship etc, the crews actions I would hope would be no different in similar circumstances should they be repeated.

    1. Dan Dair

      777 Steve,
      To the best of my recollection, most of the comments were very negative indeed,
      until some wise owl pointed-out that it was a -300 with the tail skid AND the associated warning devices.!
      At which point the vitriol calmed down somewhat.!
      (I can’t remember if I was one of the detractors…… I hope not.???)

      1. ghostwhowalksnz

        The current production B777-300ER dont have a tail skid.
        They seem to have been delivered from late 2013-to 2014, roughly about 8 77W were delivered to SX since that time

  2. comet

    At least it didn’t crash into the lighting fixtures at the end of the runway, or go down the grassy slope like Emirates EK407 did.

    But Melbourne’s​ Tullamarine does seem to be the place to have a tail strike.

  3. Tango

    I have a different take and its not to laud the pilots.

    They should have had more thrust to start with, the good piloting was the after the screw up part (Pel Air)

    They had a hard enough hit that the rear crew hear a bang, they had no indicators when they should have.

    The prudent thing to do would be to land and have it checked, not continue a long distance over the ocean flight.

    Only an actual inspection and NIC would show if there was damage.

    I don’t think a SB should be a cheerleader.

    1. 777 Steve

      Tango, please don’t display your ignorance…unless of course you are saying you know more about the product than the people that manufacture it and would ultimately be liable?
      There is a specific procedure unique to the 777-300 variant that is unlike the others, unless you knew or know this you are quite frankly talking out of your posterior.

      1. Tango

        777 Steve: Let us discuss your gross ignorance.

        Recommendation is to add thrust when you have windy conditions.

        As a pilot I can also confirm that it is SOP with any aircraft as gusts can drop out from under neat you.

        If fact, to take off in gusty condition of that magnitude is the worst possible piloting.

        they then over rotate hitting the tail skid (and not that is not part of the procedure buster_)

        So they ignored the critical recommendation, then they followed it? Wow.

        And for that they get a pat on the back.

        You have to wonder what they hand out when you crash one, a gold cup?

  4. JW (aka James Wilson)

    The incident was handled in accordance with Boeing procedures after the tailstrike occurred, but to my mind there’s an important question that hasn’t been answered. Based on the report, the crew obviously recognised the gusty conditions, yet persisted with a reduced thrust take-off. Why did they not recognise the threat posed by the conditions and use a higher take-off thrust setting? Training? Experience? Increased thrust in gusty conditions significantly mitigates the threat and has been recommended by both Boeing and Airbus for many years.

    1. Ben Sandilands

      JW,
      Agree. The airline appears to concede that point, as covered toward the end of the full version of the ATSB report.

      1. Dan Dair

        I would suspect that it is/was a hole in the training procedures.?
        Line pilots are expected to follow the on-board computer thrust recommendations. As Ben pointed-out, it’s good for the engine & for fuel economy, so it’s good for the company.!

        As with the old-chestnut of line pilots with not enough hand-flying experience, this is another example of qualified pilots deferring to the computer system, as much as anything because that’s what that company wants.?
        Hopefully SIA will learn from this & remedy this specific issue……..
        & maybe they’ll not be the only airline to take onboard this particular lesson.?

        1. Dan Dair

          Clearly, the computer system has no idea what the weather’s like.!!!

          1. ghostwhowalksnz

            It should ! I thought temp wind etc was put into the computer.
            I found this rule of thumb for gusting winds..
            “During landing ( same on takeoff) you must add half the gust factor to your final approach speed. Thus if tower reports the wind 240 at 18 gusts 28 it is advisable to add 5 kts to your airspeed.
            As most accidents occur during takeoff or landing, I cant see how praise for the pilots (for continuing on) is justified. Thats isnt what the accident investigation is about- the primary cause.
            It must be Affirmations Month at ATSB.

          2. 777 Steve

            The key part in the report for me is this…
            “Both flight crew recalled hearing another aircraft query the tower controller if windshear was reported by the flight crew of the go-around aircraft. The tower controller stated, ‘no windshear, just unstable conditions’. Two aircraft departed prior to SYG with the tower controller again advising the departing aircraft that no windshear was reported. At about 1145, SYG was then cleared for take-off from the full length of runway 34.”
            It shows to me beyond a shadow of doubt that the crew were perfectly aware of the potential threat…but in the absence of a clearly defined and active trigger with respect to their procedures they assessed that reduced thrust was appropriate. In a way it’s the difference between a resilient mindset and a rule bound mindset. As a general principle there are wider social and educational issues at play here, the average Singaporean is compliant thinker, it’s rare to find someone that will step out of line so to speak, the trait is rare. Conversely the more western mentality is to think for yourself a bit more and use experience as a tool and procedures for guidance rather than be bound by them..particularly when circumstances fall into grey areas..as in cases like this they invariably do.
            If the crew had used TOGA thrust, the likelihood of the skid contacting the runway would have been reduced…but not eliminated, so it was a factor but not the determining factor.

          3. Tango

            You clearly do not understand the weather winds and affects on aircraft.

          4. Dan Dair

            Ghostwhowalksnz,
            My point is that clearly the computer doesn’t KNOW what the weather’s like. It knows what information the pilots & it’s software have provided it with.!

            It’s the pilots job to assess the weather conditions & decide upon the best course of action. All-concerned here (including the ATSB) seem to concur that significantly increased thrust would have mitigated, if not completely resolved this situation.?

            As I suggested earlier, a hole in SIA’s training.?

      2. comet

        As far as preventing future events goes, using increased thrust is the crux of the issue.

        It makes me wonder why the ATSB report doesn’t highlight this issue, rather than confine it to a small mention towards the end. And why does the ATSB praise and exonerate the crew, who caused this potentially dangerous situation in the first place?

        1. ghostwhowalksnz

          Likely Singapore Air had final say over the report wording. 20 years ago they would got to the point and drew the relevant conclusions.
          Now these things are re- written by lawyers who can brow beat civil servants who are concerned for their career.

  5. George Glass

    Decisions in the cockpit can be quite simple,but with great consequence.
    “We can do it with 48 degrees assumed temp. But its pretty rugged out there.Wana to go max.thrust?
    No, reduced thrust will be ok.”
    Simple as that.
    A judgement call that happens a million times everyday,a million times around the planet,along with millions of others
    Its called Airmanship.
    Amazing aviation is so safe,isnt it?

    1. comet

      Reduced thrust = save money

  6. Tango

    High gust, way too low an airspeed to overcome those, lets use econ thrust in a very unsafe sitation/

    To make it worse, lets over rotate .

    Followed up by a gold star by ATSB.

    Pel Air pilot should have gotten a gold cup by that standard.

    MH370 pilots, well lets add up the fatalities, maybe $100,000 base rewards?

    How about a lot of hours in the simulator to correct lousy piloting and judgment?

    1. Mick Gilbert

      Tango, the ATSB did not give the crew a “gold star” for using a reduced thrust take-off; let’s be very clear on that. In fact, the ATSB notes that a higher thrust setting, per the Boeing FCTM, would have most likely minimised the chance of a tail strike. They also note that the SQ FCOM does not align with the FCTM in that it “… does not contain direct guidance regarding take-off thrust setting requirements in gusty wind and strong crosswind conditions.” SQ are addressing that matter.
      What the ATSB gives due credit to the flight crew for is what they did after the tail-strike. The report says,
      “… this incident provides an excellent example of flight crew managing a non-normal operation. Throughout the non-normal occurrence period, the flight crew communicated with each other, air traffic control and the cabin crew, which allowed all relevant information available to be gathered. The flight crew demonstrated effective crew resource management and decision making resulting in the flight being able to continue to destination without compromising safety.”
      That’s a “gold star” for handling the incident, not causing it.
      You don’t improve safety by just highlighting and “penalising” dysfunctional/deviant behaviour, it is also improved by highlighting and reinforcing functional/compliant behaviour; stick, carrot.

      1. comet

        Is it the ATSB’s roll to highlight functional/compliant behaviour, or to highlight what went wrong to prevent future occurrences?

        It would have been more useful for the ATSB to have an indepth investigation into why the crew opted against using a higher-thrust takeoff.

        What were their thoughts. The roll that commercial pressures obviously played. The amendment of rules, policies and commercial culture regarding low-thrust takeoffs.

        1. Mick Gilbert

          Comet, it’s both; highlight functional/compliant behaviour AND highlight what went wrong to prevent future occurrences.
          This from the ATSB’s website;
          “The ATSB’s function is to improve safety and public confidence in the aviation, marine and rail modes of transport through excellence in:
          – independent investigation of transport accidents and other safety occurrences;
          – safety data recording, analysis and research; and
          – fostering safety awareness, knowledge and action.”
          An in-depth investigation as to why the crew used a reduced thrust take-off wasn’t required; the reason for the reduced thrust take-off had been determined and is recorded in the investigation report –
          “The operator’s Flight Crew Operations Manual (FCOM) stated that the use of reduced thrust is standard procedure for take-off. The FCOM also listed the environmental conditions when take-offs with reduced thrust are not permitted.
          The operator’s FCOM does not contain direct guidance regarding take-off thrust setting requirements in gusty wind and strong crosswind conditions. Guidance for considering the use of higher thrust settings and rotation speeds for take-offs under these environmental conditions is provided in the [Boeing] Flight Crew Training Manual (FCTM).”
          In sum, it was standard operating procedure at SQ. It is worth noting that the crew were not oblivious to hazards associated with the weather conditions and, as also noted in the investigation report,
          “The flight crew stated that, in accordance with the operator’s standard operating procedures, they briefed the use of full climb thrust after becoming airborne to mitigate the strong and gusty wind conditions.”
          And the subsequent action taken by SQ to amend procedures is also noted in the report,
          “As a result of this incident, the aircraft operator issued circulars to all company flight crew directing operation towards Boeing’s recommendation of the use of higher thrust and rotation speed for take-off in gusty wind and strong crosswind conditions.”

          1. Dan Dair

            In conclusion;
            After the fact,
            everyone concerned has done really, really well…..
            What a pity they let it happen in the first place.?

          2. Tango

            In other words very poor piloting and I will not even use the word judgment.

  7. Tango

    Back to, their extremely poor judgment lead to brilliant team work.

    Correct reading should have been, the crew violated clear directives to increase thrust for takeoff in gusty conditions in a foolish attempt to economize.

    Said very poor to reprehensible judgment then lead to a tail strike and because the PIC over rotated trying to horse the aircraft into the air.

    While the crew checkout was per the book, which is how it should be and is expected of a crew, that would not have been necessary if they had not caused the need for that to be used in the first place.

    The crew needs to be re-trained to be able to separate out economic operations from safety issues.

    And regardless of Boeing take, when you have had a tail strike and the notify system is malfunctioned it is prudent to land and check it out.

    In no way does a lack of ability to see a leak confirm there has not been damage.

    Loss of cabin pressure will force the aircraft down to 10,000 feet. What does that do to your ETOPS?

    Loss of an engine then would put you in even worse situation as this is a very long distance over water flight.

    1. JW (aka James Wilson)

      Tango:

      “…regardless of Boeing take, when you have had a tail strike and the notify system is malfunctioned it is prudent to land and check it out.”

      Gosh, what would Boeing know? In this incident, it was the tail skid that contacted the runway, not the tail itself. The tail skid is designed to absorb the forces of a minor tail strike without causing damage to the aircraft structure. If the tail strike had been more serious and the tail had actually contacted the runway, the crew would have received a TAIL STRIKE EICAS caution, which would have required the aircraft to land at the nearest suitable airport. That did NOT happen in this case.

      “Loss of cabin pressure will force the aircraft down to 10,000 feet. What does that do to your ETOPS?”

      Depressurisation is considered as part of the ETOPS fuel planning requirements. The aircraft will have at least enough fuel to divert to the nearest suitable airport, after suffering a depressurisation at any point along the route.

      “Loss of an engine then would put you in even worse situation as this is a very long distance over water flight.”

      I suggest you take a look at a map old boy. The MEL-SIN flight is largely over land, most of it in Australia. Surprisingly enough, there are quite a number of suitable diversion airports along the route.

      1. Tango

        James: I mis-remembered the destination (tangled it up) so I stand corrected on that one.

        I did not know they had ETOPS for 10k, having had once incident a year or so in the North Pacific, it seemed they could not make it at 10k when an engine quit (will track those hours but it seems upward of 2.5 or 3.5 on the longer ones)

        That said, they certainly failed to understand you need more thrust on take off as well as in the air for the conditions.

        I don’t remember over rotation being a recommended way to get an aircraft off the ground.

        Said over rotating did cause significant damage to the tail skid system and it was a bang not a scrape reported.

        I continue to believe the prudent thing to do is to land.,

        I will note that Airbus did not have a dual engine out procedures for Sully an his co pilot to revert to.

        Boeing ahs a number of major screw ups to their credit in regards to batteries, 747-400 that retracted the slats because of an slightly out of adjustment thrust reverser cowling position switch.

        NTSB has chastised Boeing for their auto throttle quitting as a result of another mode action not deliberate on the pilots part.

        The reason they have PIC is to exercise good judgment. That includes deviating from the Aircraft mfg approach if they feel it is not covered.

        In this case I would put it, we screwed up, we have backing form Boeing to keep going so we won’t look as bad at the end by causing us more embarrassment of a re-landed flight and inspections.

        When I made a mistake I was taught to bite the bullet and take what I had coming.

        1. JW (aka James Wilson)

          “I did not know they had ETOPS for 10k, having had once incident a year or so in the North Pacific, it seemed they could not make it at 10k when an engine quit (will track those hours but it seems upward of 2.5 or 3.5 on the longer ones).”

          The applicable US regulation [14 CFR § 121.646(b)] states the following:
          “No person may dispatch or release for flight an ETOPS flight unless, considering wind and other weather conditions expected, it has the fuel otherwise required by this part and enough fuel to satisfy each of the following requirements…
          (B) Fuel sufficient to fly to an ETOPS Alternate Airport (at the one-engine-inoperative cruise speed) assuming a rapid decompression and a simultaneous engine failure at the most critical point followed by descent to a safe altitude in compliance with the oxygen requirements of §121.333 of this chapter.”
          The rules adopted by European countries, Australia and others are similar and are based on the ICAO Annex 6 requirements.

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