Chasing the Needles…

by

bordinstrument_232x232-rgb_tcm586-46594Pilots learning to fly on instruments are told by their instructors to be careful not to “chase the needles”. It is expression that refers to the gauge that is used to insure an airplane is flying inside an imaginary cone of safety as it descends toward a runway. The pilot’s goal is to keep the cross hairs lined up perfectly (as they are in this image) – meaning the aircraft is centered vertically and horizontally on the path toward a safe landing. Pilots who are new to flying with this gauge as a navigational reference tend to over-correct when the sensitive needles show the plane is in the wrong place. They “chase the needles” – flying S-turns – or porpoising up and down – as they struggle to find the sweet spot in the middle. More often that not, “chasing the needles” leads to a botched/aborted approach.

And so it goes for aviation accident investigations. As you read the daily dispatches about the current state of play in the search for the cause of the crash of Colgan/Continental 3407, I urge you to avoid “chasing the needles”.

Remember, a plane crash is almost always the result of a chain of seemingly unrelated factors.q400_turboprops

So far, it appears investigators have only ruled out one significant thing: the aircraft itself. It seems the Dash-8 Q400 controls, systems and engines were all operating as per design. That leaves the weather, the instrument landing system and the human beings in the cockpit on the list of possible causes or contributors to this crash.

We know the plane had picked up a pretty good coating of ice that night – the crew reported that fact to controllers . Was that, in and of itself, enough to bring the plane down? Highly unlikely. Did it change the way the airplane performed – making it important for the crew to fly a little faster so it would not encounter an aerodynamic stall? Very likely. Would it have been wiser for the crew to disengage the autopilot and fly the airplane “by hand” through the ice – so they could “feel” the effects of the ice? You bet.

ils23-kbufWas the Instrument Landing System for runway 23 operating properly that night? A few weeks before the crash, Southwest Airlines pilots warned of a glitch caused by terrain beneath the approach path to runway 23 that might cause an aircraft on autopilot to suddenly pitch up – chasing the needle – trying to intercept an errant radio beam. The FAA downplays this as a factor – saying the glitch is noted on charts. But I do not see any reference to this on the government issued diagram (“approach plate” in pilot parlance) for the Instrument Landing System approach to runway 23 at BUF. Apparently this would only be a factor for aircraft turning right toward the approach to runway 23 from the north. Colgan/Continental 3407 was turning left from the south. Stay tuned on this one.

Finally, did the crew manage the aircraft properly given the conditions and circumstances that night? Was the ice a distraction that caused them to ignore some basic rules of airmanship (like maintaining a safe speed)? Or was the ice a red herring – that caused them to make matters worse when the plane automatically tried to pitch the nose downward (apparently to prevent an aerodynamic stall)? Did they presume it was a so-called “tailplane stall” – wherein the recovery calls for the pilot to pull the nose up? (see previous post).

Or was it a combination of some or all of these factors? Don’t chase the needles.

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18 Responses to “Chasing the Needles…”

  1. steelopus Says:

    Miles, you provide such great insight.
    Living about 60 minutes from the crash site, this is big news in town, but no media outlet is providing the facts and potential causes as clearly or effectively as you are.
    Keep it up, you’re an asset to the community.

  2. Jon Says:

    I think you are spot on with this blog miles.

    I have a feeling that the whole industry has been chasing the needles since the deregulation bill was signed. Folks, its better to do something ”right” and then figure out how to pay for it than to figure out how to do soemthing ”cheap” and hope that its right enough.

  3. Bo Henriksson Says:

    Miles,
    On the BUF ILS23 Jeppesen plate (used by airlines, I’m sure Colgan too) clearly notes the glideslope as unusable beyond 5 degrees right of course. Either way, it’s another red herring since the flight guidance system will not capture the glideslope before the localizer.
    It is an old truth that the initial guess at the cause of an accident is usually wrong. That’s going to be true this time to..

    Bo
    Captain EMB146

  4. Phil G. Says:

    Hey Miles,

    I gotta say that I only wish you had a voice on a larger platform to share your insights with. Particularly regarding this area of expertise. I know from whence you came, this was and remains your expertise. But I don’t understand why the media chooses to glance over certain facts or just regurgitate the innuendos endlessly without concrete investigation.

    I’m gonna start feeding your blog to my Facebook page. I enjoy your articles even if I don’t always comment. Thanks and keep up the great work.
    pg

    e2spg.edbd

  5. CNNfan Says:

    Miles,

    These comments are not intended to offend news business executives. It is just simply expressing the obvious truth about how viewers feel.

    Here we are again, with the latest headlines:

    NASA SATELLITE CRASHES MINUTES AFTER LAUNCH

    A NASA SATELLITE LAUNCHED EARLY TUESDAY WAS HAVING DIFFICULTIES, NASA REPORTED.

    It truly feels like all viewers are unanimous that they are not doing a proper job without you. The news executives, for the sake of the viewers should please reconsider, if that is an option.

    I am sorry to be off topic but I don’t know where else to put this. Please know that I do not mind at all if you delete this comment, especially for sounding like a broken record, or for any other reason. I don’t need an explanation.

  6. Ron Says:

    Miles : What do you think about the Turkish aircraft’s crash in Amsterdam? Investigators say the engine must have failed and stalled to cause the aircraft to just ‘fall’ out of the sky.

    http://news.bbc.co.uk/2/hi/europe/7913538.stm

  7. Mike Says:

    Just passing by.Btw, your website have great content!

    _________________________________
    Making Money $150 An Hour

  8. Eric Says:

    Miles,

    The FAA standard for annual proficiency checks requires pilots to demonstrate an impending stall recovery by taking a plane to the shaker and recovering while maintaining altitude. Operationally this means full power and hold the pitch until the speed recovers. If for some reason the plane went into stick-pusher before this recovery was complete (say, delayed reaction by the pilots, ice buildup increases stall speed, etc) the same response would be deadly. When the pusher pushes you push with it and certainly do not maintain pitch or altitude. But that doesn’t get trained because you’re never supposed to get to pusher. That’s a nasty catch that is not often noted: the correct stall recovery procedure changes when a stall progresses from impending to occurring.

    This may or may not have contributed to Colgan but from what I hear it sounds like the crew did try to override the pusher while executing a stall recovery. So did the Pinnacle crew a few years back.

  9. Doug Rozendaal Says:

    Miles,

    I found your blog from your Linkedin page. Thanks for accepting my invite.

    What an excellent analysis of the entire situation…… Rational and insightful, and restraint from jumping to conclusions…. What a concept….. Too bad that’s not what the national media is looking for! Instead we all endured uninformed and emotional reporters sensationalize this story for weeks now… What a travesty.

    I have no evidence, but my fear is that we will learn that this accident occured, not because of the ice, but because the pilots were more concerned about a little ice than flying the airplane….. Airplanes will fly with ridiculous amounts of ice on them if the pilots never stop flying them. (BTDT) When the pilot says “OMG, we are in the ice, what is the company policy, or, they told us we might die.” It is not an ice problem, it’s an experience problem.

    The CVR and FDR will tell the tale. If this proves true, it will sharpen the point that the new crop of pilots that went to Aviation Colleges and graduated to the right seat of a turbine powered commuter have a far different skill set than those who grew up flying checks in a Twin Beech, C-402, or a Navajo.

    Freight hauling gave the youngsters like me to learn from experience instead of textbooks. A couple times it almost killed me, and that is the point. If I had failed, it would have only been me, a tired old Twin Beech and a plane full of boxes that was lost. Not a shiney new turbine with a crowd in back.

    I know the questions are easy and the answers are hard. My answer is a Colemill B-55 whenever possible….

    Tailwinds,
    Doug Rozendaal

    PS, Did you get a chance to watch Red Tail Reborn?

  10. JohnDowd Says:

    There is a phenomenon that is called ‘tampering’ in manufacturing. It is, in effect, over-adjustment. This has been modeled and what it shows is that when a process is operating with onlynatural variation, if one were to continually hunt the aim (chase the needle) this action actually increases variability, often making matters worse.

  11. Wondering Says:

    The NTSB issued an update about 3407 on March 25. I’m wondering if Mr. O’Brien and any of the commenters here have reactions or feedback. I knew multiple passengers including a good friend, so I’m still trying to make sense of it all, to the extent possible, which I know can’t be much.

    Thanks in advance for any thoughts or explanations in lay person terms.

    http://www.ntsb.gov/pressrel/2009/090325.html

  12. Wondering Says:

    One question I have about the NTSB’s 3/25 statement is what might have caused the speed to slow down to 130 kts as the plane approached landing? If icing wasn’t a major factor, why might it have gotten dangerously slow enough to (properly) trigger the shaker? Also, regardless of what caused the slowing to 130 kts, then at that altitude was there likely room enough about the ground to recover if nose-lowering had been combined with increased power (instead of rising the nose)? Thank you for any insights and explanations.

    from NTSB 3/25: “…Preliminary airplane performance modeling and simulation efforts indicate that icing had a minimal impact on the stall speed of the airplane. The FDR data indicates that the stick shaker activated at 130 knots, which is consistent with the de-ice system being engaged. …”

  13. Doug Rozendaal Says:

    Here is what the report is saying with out saying it….
    The 1G stall speed for a clean airplane is 105 kts.
    he airplane was at 1.42G based on a pull at the stick shaker, presumably from one of the pilots.
    The squareroot of 1.42 is 1.19 multiplied x 105 kts would predict a 125 kt stall speed which is what happened and would mean that there was very little if any ice accumulation on the airplane.
    The FDR knows the throttle position and the NTSB did not report it because in these kinds of cases they piece this information out,(as they should) in deference to the families of the crew.

    It appears that the fears in my previous post are supported by this information. The pull on the yoke MAY have been a response to a perceived tail stall and had there been a tail stall, that would have been appropriate. There is, however, no indication in any of the reports so far, or is there any reason to beleive their was a tail stall.

    I predict the next NTSB report will indicate that the power had been reduced to descend and slow the airplane in perpetration for the approach and it was never increased at level off. A likely reason for this, as I said previously, is because the crew was preoccupied with the icing encounter even though it was insignificant.

    This is a sad story and some might find it an indictment of the pilots. IT IS NOT! It is a systemic problem. In the past pilots worked their way through the ranks, first instructing and the flying freight and passenger charter in light twins and then to the airlines. Today these young pilots come from Emery Riddle or NSDU straight to the right seat of a Commuter. They have incredible skill and and excellent training. What they lack is experience and you can not teach it in a simulator or a classroom. It comes from flying in the crappy weather by yourself. The advent of electronic check clearing and the reduction in the military training is the cause and this accident is a symptom of this breakdown in the system.

    These pilots reacted to the best of their ability with the training and experience that they brought to the situation. It is not their fault, it is not Colgans fault, it is a system problem and I don’t have a solution.

  14. wondering Says:

    Doug R., Thank you for the reply.

    Could you please explain your reference to “advent of electronic check clearing”? Your writing is tremendously understandable, but that phrase sailed over my head.

    On the broader question of the solution:

    Even though there’s no longer as many cargo pilots, couldn’t airline co’s feasibly have their pilot crews in training fly a couple additional months of practice flights without passengers in a variety of conditions (including winter nights with icing conditions) on the type of planes they’ll fly and have the pilot actions graded and reviewed carefully during and after by trainers?

    Perhaps some of that is done already, but would it cost all that much to add more real flights like that before beinig allowed to fly passengers?

    Also, upon changing the type of plane a pilot is flying (for example, changing from Saab to the Q400) when that has significant different characteristics, would requiring say a month or so of flights without passengers at that point also be feasible – also with review and grading?

    Those ideas would add costs for fuel and aircraft use, but I wonder how much it would really need to raise the cost of tickets in the context of the whole revenue stream and airline economics.

  15. Doug Rozendaal Says:

    Wondering,

    First off, I neglected to say in my first post, I am sorry for your loss. I have lost many friends in aviation, and it is never easy.

    Also, it is important to keep any discussion of aviation in perspective. Traveling on a scheduled airliner in America is the safest mode of transport ever conceived, and the long term safety stats continue to improve.

    Per passenger-mile it is safer than walking, driving, riding a bike, a train or a bus. Moving about has risk associated with it, and while it is hard to accept any loss, the safety record of the system is incredible. That does not relieve anyone from desiring to do better.

    To your questions: In the “old” days, pilots grew up hauling cancelled checks an UPS or FEDEx freight in tired old light twins in the middle of the night in terrible weather. As an aspiring pilot you did that for a year or two and if you survived, the airlines figured you were a pretty decent pilot. Not everybody survived….

    Banks now clear checks electronically, so there are a lot less freight dogs.

    With regard to non-passenger flights, typically the first time an airline pilot flies a new type of airplane there are passengers in back. All the training is done in the sim, and while that might seem scary, it is not, the sims very accurately reflect the airplanes. And if pilots did fly without pax, it would cost a fortune. Further,the experience I am talking about is years, not months.

    Flying used to be more like the medical community with a long residency. When the pilots at the top were making $250K or better pilots would put up with low pay for several years with the promise of the pot of gold at the end of the rainbow. A pilot starting today will never make that kind of money. And who wants a to spend a career being harassed by the TSA in an industry that is marginally financially stable with layoffs and furloughs almost a certainty. It is not a good road we are on here in aviation…. As I said, this accident is a symptom of a system problem.

    Tailwinds,
    DougR

  16. wondering Says:

    Thank you again, both for your explanations and condolences.

    Your points about economic realities do indeed make sense.

    Still, although “months” (or suppose “weeks”) would be nowhere nearly as useful as “years” (which happened in the old days) I have to wonder if a well-designed way to have a few empty real flights focusing on creating some some more challenging scenarios to be encountered in a safe way – potential moderate icing, other weather issues, recovery from accidental low speed, stick shaker resonse, stick pusher response, etc. – maybe could happen in an economically viable supplement to sim training.

    By far most training would still be in the sim, but also there’d be some in-flight experience of a few of the more more dangerous situations with close critiques by experienced peers before flights with passengers.

    Just trying to envision what kinds of things might be a practical, useful, constructive improvement.

  17. Doug Rozendaal Says:

    Below is the latest parcel in the piecing together of the facts in this accident. In my March 10th message above I predicted this was an experience problem…. This discussion highlights the limited experience of the crew.

    Sadly I predict the next piece of information will be the FDR and I predict that it will say that the throttles were at idle and the airplane was slowing far below it’s normal approach speed while the conversation quoted below about the ice was going on.

    Remember the airplane stalled only 5 knots above it’s predicted stall speed. Hardly an excessive amount of ice. Maybe the most either of the crew had seen, but not an excessive amount.

    I repeat, the crew did the best job they could with the experience they had, but their experience bucket was very low.

    Tailwinds,
    Doug Rozendaal

    The AP report transcript.
    “It’s lots of ice,” Shaw said.
    “Oh yeah that’s the most I’ve seen, most ice I’ve seen on the leading edges in a long time, in a while anyway I should say,” Renslow replied.
    Renslow then remarked that he’d flown about 625 hours in the region before he was hired for this job by Manassas, Va.-based Colgan Air.
    Shaw replied, “I really wouldn’t mind going through a a winter in the Northeast before I have to upgrade to captain. … I’ve never seen icing conditions. I’ve never deiced. I’ve never seen any. I’ve never experienced any of that. I don’t want to have to experience that and make those kinds of calls. You know I’dve freaked out. I’dve have like seen this much ice and thought, `Oh my gosh, we were going to crash.’ ”
    “I would’ve been fine,” Renslow replied. “I would have survived it. There wasn’t, we never had to make decisions that I wouldn’t have been able to make but … now I’m more comfortable.”

  18. wondering Says:

    Doug, thanks for updating this with your feedback.

    I’m curious whether you think neither of the pilots vocalizing anything during descent about speed is unusual, and also an experience issue? Given the industry practicalities regarding experience at this point, what shoudl be done? More or different kinds of monitoring or management?

    So far does it sound like it something like a 5-part series of mistakes? 1. entering (“bugging”?) too low a descent speed (i.e., not boosted for vref offset), 2. neither pilot noticing the speed condition indicated the “red barber pole” (as it was called in Tuesday’s hearing) warning indicator, 3. retracting flaps and/or gear after the shaker went off (an answer said those shouldn’t have been retracted but it wasn’t clear how much of an issue those were), 4. pulling up nose against pusher’s force instead of lowering nose to gain speed, and 5. adding only 75% power after the shaker (Mr. Sumwalt’s follow-up question clarified that happened).

    My total amateur take was it sounded like the NTSB’s 1st day questions intended to highlight those specifics about the event.

    Of those 5 (if that’s the right number), I wonder if all are experience issues vs. panic vs. training vs. fatigue vs. inattention….. I suppose each can be some combination of all.

    Naturally all this can never make sense when I think of my friend and everybody involved RIP, but trying to understand as much as possible as this unfolds feels like an important thing to do.

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