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Air Traffic Monitoring => Aviation Audio Clips => Topic started by: medflight5 on December 20, 2011, 02:32:28 PM

Title: TBM-700 N731CA crash outside of MMU
Post by: medflight5 on December 20, 2011, 02:32:28 PM
Flight was Teterboro to Atlanta and it went down this morning around 10:05L just to the SW of MMU on I-287 in NJ.

This sound clip was created with archives from KEWR New York Departure just after the aircraft's departure from TEB around 09:50L and then the handover to NY Approach Liberty West/South. The TEB tower feed was inop and there is no feed covered for the NY Center freq this aircraft was communicating with at the time of the crash.

Also included are communications between NY Appch (Liberty West/South) and other aircraft around the time of the crash, advising of moderate to extreme rime and mixed icing between 13,000 and FL180.

Using http://www4.passur.com/ewr.html, make the time Dec 20, 2011 10:03am. Set zoom to 20mi and click "Start". Click on the aircraft near Morristown (top left of radar screen)... It's initially a helicopter but then changes to the N731CA aircraft. Notice the altitude go from 18,000 to it's disappearance in about 60 seconds.

Based on the ATC recordings, reports of severe/extreme icing throughout the area within this aircraft's climb altitudes, and the rapid decent at the time of crash... seems plausible this crash could have been icing-related. Any thoughts?

Very unfortunate, regardless. But hopefully we (pilots) can all learn something from this incident.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: N53020 on December 20, 2011, 03:03:15 PM
Yep indeed does sound like a icing incident.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: StrongDreams on December 20, 2011, 03:09:54 PM
Is that rate of decent even plausible?  I wonder if the transponder or altimeter was wrong.  From 18,000 feet to ground in 1 minute is 180 miles per hour straight down...it seems like there should be some horizontal component to the movement.  Even AF447 was only falling at 10,000 feet per minute, while keeping around 60 knots forward motion, if I remember right.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: mielsonwheals on December 20, 2011, 03:18:38 PM
I definitely think ice might have had something to do with it. Although I understand the TBM-700 is certified for all IFR flight conditions, and is equipped with de-icing boots. Perhaps these boots were never used, and the forces on the wing became too much during the rapid/ uncontrolled descent, and broke one of them off?

Here is a PIREP that reported moderate - severe icing nearby, about 40 mins later at a close altitude:

   PIREP 15:42Z 12/20/11
   SMQ UUA /OV BWZ250030/TM 1542/FL140/TP MULTIPLE/IC MOD-SEV RIME/RM ABE FL140-175

Title: Re: TBM-700 N731CA crash outside of MMU
Post by: VampyreGTX on December 20, 2011, 03:25:52 PM
Remember, boots are not foolproof. Icing can overwhelm the boots and create a 'cavern' effect, creating a void under the ice for the boot to expand with no effect on the ice buildup (not sure how to explain it a little clearer). With the reports of severe icing and airliners mentioning issues fending off the ice, I'm not sure the TBM with just boots could handle that type of encounter.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: mielsonwheals on December 20, 2011, 04:18:18 PM
Yes, sounds like the pilot was made aware of the icing conditions, so I'm sure he was indeed using all anti-ice equipment he had available. Very sad.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: medflight5 on December 20, 2011, 04:57:41 PM
Here's another clip I edited of MMU tower just after the crash. It includes the responses of the news helicopters and NJ State Police medevac helicopter N5NJ.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: toeknee25 on December 20, 2011, 10:09:26 PM
Truly a dark day for general aviation. Not only this crash but there were also crashes in Denton and Waco Texas :(

And NYC Aviation reminded me that December 20th has had some other crashes in the past too.. Continental Airlines Flight 1404 in Denver and American Airlines Flight 965 outside of Cali, Colombia.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: ArnieF on December 21, 2011, 05:16:29 AM
http://www.cnn.com/2011/12/20/us/new-jersey-plane-crash/index.html?hpt=hp_t3 (http://www.cnn.com/2011/12/20/us/new-jersey-plane-crash/index.html?hpt=hp_t3)
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: etobias on December 21, 2011, 09:34:30 AM
When told of the icing the pilot tells ATC: "We can go right through it."  That's the real cause of this tragedy.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: David7700 on December 21, 2011, 11:07:49 AM
Is that rate of decent even plausible?  I wonder if the transponder or altimeter was wrong.  From 18,000 feet to ground in 1 minute is 180 miles per hour straight down...it seems like there should be some horizontal component to the movement.  Even AF447 was only falling at 10,000 feet per minute, while keeping around 60 knots forward motion, if I remember right.

Yes. Reports are he lost a wing due to the stresses on the airframe.  RIP to that family and their friend.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: David7700 on December 21, 2011, 11:09:00 AM
When told of the icing the pilot tells ATC: "We can go right through it."  That's the real cause of this tragedy.

+1
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: Wilky10 on December 21, 2011, 12:24:37 PM
I currently fly 2 TBM700s and have been in icing conditions on multiple occasions without any complications. The boot system on these aircraft have cycles. There are 3 different boot segments on the wings and one on the tail. The inboard section of the wing and the tail operate for 7 seconds. After this cycle the middle and outboard operate for 7 seconds. Then there is a cycle of 53 seconds that the boots do not operate. There is no way to speed up this cycle. This is the one downfall of this aircraft. Due to this operation cycle, I try to avoid any areas with pireps of moderate ice if possible.

My thoughts and prayers go out to all family and friend affected.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: JT1 on December 21, 2011, 12:49:46 PM
Listing to the audio clip I was reminded of a few things.  It's always good to know your abilities as a pilot and the abilities / limitations of the aircraft your flying.  When a pilot is over confident in their abilities, and /or over confident in the abilities of the aircraft they are flying, that is usually when bad things happen.  It's very hard at this point to say what caused the accident as sometimes many factors can play a role.  But given the weather conditions, it's easy to speculate or focus on ice.  Having experience in a variety of single and multi-engine aircraft, but no time in the TBM-700 I can only speak in general and not specific to this accident.  (Please note, I am not an expert and I feel we are always learning no matter how much experience we have in flying)  De-ice boots can be quickly overwhelmed in moderate to severe icing, as well as a single engine turbo prop can be quickly overwhelmed too.  When the boots are turned on too early, instead of the ice breaking away, it can form a barrier along the outer limits of the boot extension (as mentioned in a post above).  At that point the boots become useless as the ice has caused a cavity for the boots to expand, contract, and never breaking the ice away.  When an aircraft tries to climb too aggressively through ice, a reverse horse shoe effect can form along the leading edge of the wing, looking like: )C.   ")" -being the shape of ice buildup and "C" -being the leading edge of the wing.  Props can be overwhelmed by ice which can reduce the amount of thrust.  Ice can make the prop off balance causing vibration and even throwing ice, which can be alarming to say the least.  Many de-ice systems in light aircraft are designed to help in the event of an unexpected encounter with ice, buying time to help get out of a dangerous situation.  From a human factors perspective, ice buildup can become very stressful and distracting.  A white knuckle grip on the controls and looking back at the wings can cause sudden pitching up or banking in a situation where the aircraft is already struggling with performance, in icing, making a dangerous situation deadly.  An auto pilot can trim an aircraft to unsafe attitude or power setting while trying to do what is programed in an attempt to overcome the adverse conditions that icing can cause.  Fuel tank vents can get iced over causing fuel starvation.  Pitot tubes and / or static ports anti ice system can become overwhelmed and in some situations we can forget to turn them on if it’s not done automatically by an ice detection system.  Sometimes anti ice or de-ice systems fail which can contribute to an already bad situation.
   
As for forward movement, if an aircraft goes into a spin that develops into a flat spin, usually there is very little forward movement.

I am not trying to play arm chair quarterback nor am I trying to judge the decision making of the pilot at the controls (as I know nothing about his experience and we have very little information about the accident to go on).  It's very sad when a fatal accident happens and my thoughts go out to the victims and their families.  When an accident occurs in the industry it's best to let the investigators do their job and we can all learn from the findings.  But in the preliminary stages it's best to brush up on our knowledge about the possible factors (NASA has done interesting studies on icing and the FAA has publications) and have discussions in forums such as this to get different perspectives, share experiences and learn from each other.  An accident always reminds me that they can happen and it makes me take a second look at the calculated risks that I take.  This time of year we need to remind ourselves that weather is not kind and it’s not forgiving.  Weather is indifferent and I try to take a realistic approach when going up into the elements.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: flyingiceman on December 21, 2011, 06:43:51 PM
The remarkable thing is how little time transpired between entering IMC and loss of control…4 to 5 minutes max?  Wow!  A little frightening to think that, even at gross weight, an aircraft of this stature could encounter so much ice that it becomes unflyable in such a short period of time. Flightaware provides the data:
http://flightaware.com/live/flight/N731CA/history/20111220/1400Z/KTEB/KPDK/tracklog     
Between 13,900 (start of IMC?) and 17,400 the airspeed and rate of climb falls off pretty quickly.  Unless there was a reduction in power, these data seem consistent with increasing drag associated with ice. The idiosyncrasies of the deicing boot cycles on the TBM700 mentioned by Wilky10 are noteworthy.
I think the strategy and mindset of how you approach the ice is critical.  Do you assume you won’t have a problem and plan to react if you do?  Or do you assume you will have a problem and don’t react if the problem doesn’t materialize?  There is a critical distinction between these two mindsets.  One puts you ahead of the plane the other can put you behind the airplane at a time where behind is really bad.
An example….do you fly an ILS with the mindset of “I am going to miss “or I am going to get in?  I used to assume the latter.  I hadn’t missed an actual approach in years…why would this time be any different?   So flying a ILS into IND I had it LOCKED into my mind that I was getting in.  Yeah, I briefed the missed approach instructions but my MIND had no intention of missing.  Well turns out there was no runway environment in sight at the DH.  My first reaction was WTF?  The second was to be somewhat insulted (silly as it sounds) and my third reaction was to pitch up, power up at which point I looked down to see what the missed instructions really said.  It was a disorienting experience trying to make a full power climbing turn while rereading the instructions I has read less than 5 minutes prior.  I didn’t catch up to the aircraft until I was finally reestablished on the ILS.  Beat myself up pretty bad over that experience and never forgot it.  Every approach I make today I plan on missing.  If I break out prior to the MAP/DH I take it as a positive “surprise”.
Judging by his words to the controller the pilot of 700CA certainly didn’t anticipate a problem.  He even used the words “it will be no problem for us”.  And why would it be?  Probably seen ice dozens of times and it was never a problem.  So the transition from “it won’t be a problem” to “holy crap I am in serious trouble” took less than 5 minutes.  Could you get your head wrapped around that swing in reality in a seamless fashion?   Would you have the discipline to recognize how bad it would become so quickly and initiate an emergency descent in NY airspace without hesitation?  Seems like a pretty tall order.  If you agree, plan for an escape no more than 60 seconds after entering IMC when moderate to severe is reported.  If you get surprised because it is manageable….it will be a surprise you can live with. 
It may turn out that that ice had nothing to do with this tragic event or that there were other factors like an out of envelope or overweight aircraft or a systems failure.  Regardless, assuming the worst vs. expecting the best is worth considering.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: dylanh on December 21, 2011, 09:54:47 PM
The remarkable thing is how little time transpired between entering IMC and loss of control…4 to 5 minutes max?  Wow!  A little frightening to think that, even at gross weight, an aircraft of this stature could encounter so much ice that it becomes unflyable in such a short period of time. Flightaware provides the data:
http://flightaware.com/live/flight/N731CA/history/20111220/1400Z/KTEB/KPDK/tracklog     
Between 13,900 (start of IMC?) and 17,400 the airspeed and rate of climb falls off pretty quickly.  Unless there was a reduction in power, these data seem consistent with increasing drag associated with ice. The idiosyncrasies of the deicing boot cycles on the TBM700 mentioned by Wilky10 are noteworthy.
I think the strategy and mindset of how you approach the ice is critical.  Do you assume you won’t have a problem and plan to react if you do?  Or do you assume you will have a problem and don’t react if the problem doesn’t materialize?  There is a critical distinction between these two mindsets.  One puts you ahead of the plane the other can put you behind the airplane at a time where behind is really bad.
An example….do you fly an ILS with the mindset of “I am going to miss “or I am going to get in?  I used to assume the latter.  I hadn’t missed an actual approach in years…why would this time be any different?   So flying a ILS into IND I had it LOCKED into my mind that I was getting in.  Yeah, I briefed the missed approach instructions but my MIND had no intention of missing.  Well turns out there was no runway environment in sight at the DH.  My first reaction was WTF?  The second was to be somewhat insulted (silly as it sounds) and my third reaction was to pitch up, power up at which point I looked down to see what the missed instructions really said.  It was a disorienting experience trying to make a full power climbing turn while rereading the instructions I has read less than 5 minutes prior.  I didn’t catch up to the aircraft until I was finally reestablished on the ILS.  Beat myself up pretty bad over that experience and never forgot it.  Every approach I make today I plan on missing.  If I break out prior to the MAP/DH I take it as a positive “surprise”.
Judging by his words to the controller the pilot of 700CA certainly didn’t anticipate a problem.  He even used the words “it will be no problem for us”.  And why would it be?  Probably seen ice dozens of times and it was never a problem.  So the transition from “it won’t be a problem” to “holy crap I am in serious trouble” took less than 5 minutes.  Could you get your head wrapped around that swing in reality in a seamless fashion?   Would you have the discipline to recognize how bad it would become so quickly and initiate an emergency descent in NY airspace without hesitation?  Seems like a pretty tall order.  If you agree, plan for an escape no more than 60 seconds after entering IMC when moderate to severe is reported.  If you get surprised because it is manageable….it will be a surprise you can live with. 
It may turn out that that ice had nothing to do with this tragic event or that there were other factors like an out of envelope or overweight aircraft or a systems failure.  Regardless, assuming the worst vs. expecting the best is worth considering.

^^^^^ Quite possibly the best story/reply/advice I've read online. 

The "beat myself up pretty bad" hits home. The road to where we are at in our professional pilot/controller careers is littered with these moments.  (lord knows I've had my share). The feeling of invincibility comes from doing the same thing over and over and not getting bit.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: Flyboy77 on December 21, 2011, 11:03:22 PM
Remember, boots are not foolproof. Icing can overwhelm the boots and create a 'cavern' effect, creating a void under the ice for the boot to expand with no effect on the ice buildup (not sure how to explain it a little clearer). With the reports of severe icing and airliners mentioning issues fending off the ice, I'm not sure the TBM with just boots could handle that type of encounter.

Ice Bridging does not exist in modern boots systems and they are not susceptible to run back according to the manufacturers.  However Ice accretion rates should be watched carefully.  When Airliners are calling sever ice you better avoid the area...
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: SASD209 on December 22, 2011, 12:55:05 AM
Just an observation about the 2nd recording of the response...is it me or does it seem like the news choppers are like vultures descending on some prey? I understand the need for the press to get the story, it just seemed a bit unsettling knowing 5 people had just died and the news choppers are racing to get the first video of it. Oh well, YMMV. RIP to those lost.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: aviator_06 on December 22, 2011, 08:16:28 AM
Very sad to here. Thoughts and prayers with their families.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: Hollis on December 22, 2011, 09:15:31 AM
Severe icing = rapid ice accretion, (less than 5 minutes) partial loss of lift, increased drag, causing entry into the back side of the power curve, loss of roll control and resultant stall-spin.
Been there, done that.
Recovery? Nose down (way, way down), throttle(s) back, controls neutral, then hopefully get to an OAT of 34F or higher and wait until the ice sheds enough to get full contol again.
 
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: FR8K9 on December 22, 2011, 03:16:58 PM
I am not familiar with the TBM 700 but in addition to the icing issue another factor the NTSB is sure to consider is the loading of the aircraft.  With five passengers, a dog, luggage, possible Christmas presents and the fuel on board for the trip, the permissible weight and balance limitations may have been exceeded.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: notaperfectpilot on December 22, 2011, 04:24:34 PM
I wonder if it was both? Being over weight and ice didn't help matters either.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: DrCox on December 22, 2011, 05:37:47 PM
I am ATC and it still amazes me how many pilots listen to the weather warnings and still choose to fly into the affected area. We shake our heads when we see it. It happens so often. I dont understand it. When you fly there are risks. When you fly in IFR there are greater risks. When you put passengers on board wouldnt you want to reduce the risks as much as possible? And when the passengers are children or your family wouldnt you want to even further reduce the risks?

I was once working a student pilot on his check ride. They departed and immediately their radio went bad. Not totally unusable but still bad. I informed him. He chose to continue his flight. And of course they returned nordo a few hours later. We had to put military jets in holding to accommodate his nordo landing. When I spoke to him over the phone he said he knew the radio was bad but they decided to 'go ahead and risk it'.

Now isnt flying risky enough as it is? Why further compound that by flying in controlled airspace with a known bad radio? Especially when the option to return to the airport, spend another half hour preflighting another flight school aircraft and then go off on the flight as intended with less risks?  In addition to more risk for yourself you are putting nearby aircraft at risk too by flying in controlled airspace with no communication with the tower.

This is what we dont understand. If youre going to play russian roulette with yourself thats one thing. But dont do it with passengers or other nearby aircraft.

Title: Re: TBM-700 N731CA crash outside of MMU
Post by: N62LM on December 22, 2011, 08:45:32 PM
Remember, boots are not foolproof. Icing can overwhelm the boots and create a 'cavern' effect, creating a void under the ice for the boot to expand with no effect on the ice buildup (not sure how to explain it a little clearer). With the reports of severe icing and airliners mentioning issues fending off the ice, I'm not sure the TBM with just boots could handle that type of encounter.

As a TBM pilot, I can tell you that this aircraft should have been able  handled it.  If I am not mistake here, they were talking about light to moderate icing conditions.   VampyreGTX your explanation is correct.  This will occur if the boots are activated too early.  We don't know when the Pilot decided to activate the deicing boots.  Never the less, he should have had his prop deice on and maintain a proper air speed (cockpit management) regardless of the ice. The climb is secondary.

The boots on a TBM work as follows, the inboard come on and cycle for 7 seconds, then the same with the outboard.  There is a 53 second or so delay before they are activated again.

Did the Pilot put the boots on too early..?  Was his climb too steep and the ice build up was so rapid..?  You gotta remember the TBM 700 is a very well built aircraft.  For the TBM to break up in flight, one would have to think the speed was in the range of 500+ mph.  That's just my two cents.

I would be hard press to see if there was something mechanically wrong with the aircraft.  


Prayer and thoughts to the families...
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: tonyairplane on December 23, 2011, 12:09:38 PM
The AD says to activate the boots right away.  Apparently other TBM-700s have lost control at the first sign of ice.
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/f671d6221d402b6586256a4900563e19!OpenDocument&ExpandSection=-5
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: FR8K9 on December 23, 2011, 12:20:25 PM
Here's a link to a good informative article on airframe icing that every pilot should review.

http://www.aopa.org/pilot/features/inflight9910.html
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: gsaviator on December 23, 2011, 01:50:21 PM
Ice Bridging does not exist in modern boots systems and they are not susceptible to run back according to the manufacturers.  However Ice accretion rates should be watched carefully.  When Airliners are calling sever ice you better avoid the area...

I can not speak for what the manufactures say about bridging, but I can certainly speak from my own personal experience. Ice bridging can and does occur on modern boot systems. I have seen it with my own eyes.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: N62LM on December 24, 2011, 10:09:10 AM
The AD says to activate the boots right away.  Apparently other TBM-700s have lost control at the first sign of ice.
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/f671d6221d402b6586256a4900563e19!OpenDocument&ExpandSection=-5


Not sure why the AD says that.  If you active them too early, then they are not effective at all and, when ice does start to build up during the dormant period of 53 seconds, then what..your basically f***ed..!  :|
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: tonyairplane on December 24, 2011, 10:52:36 AM
My guess is that on this particular airfoil and configuration, the laminar boundary layer gets disturbed very easily, resulting in separated flow, and loss of lift and control.  So the system has to be used immediately, just as the AD says.  It says clearly that there have been incidents and an accident due to this.

Please don't take this personally, but you fly that aircraft and apparently weren't aware of this AD - I wonder if this guy was?
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: gsaviator on December 24, 2011, 11:00:10 AM
The AD says to activate the boots right away.  Apparently other TBM-700s have lost control at the first sign of ice.
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/f671d6221d402b6586256a4900563e19!OpenDocument&ExpandSection=-5


Not sure why the AD says that.  If you active them too early, then they are not effective at all and, when ice does start to build up during the dormant period of 53 seconds, then what..your basically f***ed..!  :|


Yep your 100% right. Use the boots too early and you are screwed. Unfortunately, Most aircraft manuals now tell you to activate the boots at the first sign of ice thanks to ADs that force a suppliment to the aircraft manual. This has always been the problem with having a bureaucratic sitting at a desk making decisions about something they know nothing about.

So look at the bright side. We must use the boots at the first sign of ice, Screw ourselves from being able to use the boots again on that flight, then build more ice and crash and not be violated for braking a reg since we did exectly what the AD said. Yeah, that sounds right. "FAA" always there to help.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: gsaviator on December 24, 2011, 11:31:44 AM
My guess is that on this particular airfoil and configuration, the laminar boundary layer gets disturbed very easily, resulting in separated flow, and loss of lift and control.  So the system has to be used immediately, just as the AD says.  It says clearly that there have been incidents and an accident due to this.



The problem is really a two edge sword. You are correct saying the boudary layer gets disturbed very easily. Most new complex airfoils are very sensitive to any variation or disturbance to airflow hense why the FAA says they want you to use the boots at the first sign of ice. I have flown certain corporate jets that have (I'll keep this simple) one or two small triangle pieces the size and thickness of a dime attached to the leading edge of the wing which make a huge aerodynamic change to the airflow on the wing. Granted a corporate jet is designed to fly higher and faster than a TBM wing but it does tell one how a small item can make a difference; So, any ice accumulation can be huge.  

The next problem is how a boot actually works. I have been flying for over 21 years professionaly and a boot will not shed ice until it gets a significant amount of ice built on the surface. To little ice, and the ice will just expand with the boot and not shed. Then you can be basically screwed to the point where you cannot shed the ice properly once more ice builds.

The problem is certainly a catch 22.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: phaques on December 24, 2011, 05:53:02 PM
Medflight5 -

Can you share the precise feeds - and time slots - you used to piece together your montage? I can't find them in the archives.

Thx.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: Jason on December 27, 2011, 02:58:48 PM
Here's an interesting weather analysis from Scott Dennstaedt, a former NWS meteorologist, regarding the TBM700 crash.

http://avwxworkshops.com/forum/read.php?8,443
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: rduke007 on December 28, 2011, 01:15:12 PM
I see a profound lack of two issues being discussed in this conversation.
1. The effects of high AOA on icing characteristics.
2. The type of autopilot available to the TBM 700, and most-likely mode it was in (if on) at the time of the upset.
Most aircraft that don't have autothrottles would have either pitch hold, or rate hold. I have found the latter easier to use predictably in the light aircraft i fly, and use autopilots a lot, particularly during single pilot IFR.
Many booted types have had difficulty shedding ice in anything other than clean configuration straight & level flight. A lot of operators stopped flying this type of equipment (booted aircraft) in northern latitudes for transport category after the ATR Roselawn accident.What if the ice accreted where it wasn't easily seen?
Departures in this airspace often provide a host of distractions that could keep one focused on nav related tasks while the autopilot continued to sacrifice airspeed to try & regain it's programmed FPM climb rate. It may not be possible to determine whether the autopilot was even engaged, although microscopic analysis can usually tell if a lamp was illuminated during an accident sequence (filament stretching, as opposed to the cold fracture one would find if unlit)
It is also easy for us instructor types to say 'yes' to someone who has at least met the minimum requirements (i.e. instrument rating) and has equipment which appears, at least on paper, to handle a good share of the weather thrown its way.
It is disconcerting to those who fly to think it could happen to us, so we rationalize and eventually find "pilot error."
There is hazard in stopping there, and failing to understand how the combination of a recently certificated instrument pilot, an aircraft that appears on the surface to be all weather capable, and instructors who don't necessarily have to follow any specific syllabus for the transition from the trainer to the TBM. We don't teach judgment, but what we do as instructors has the largest impact on whether the pilots we turn out will go on to develop good judgment.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: medflight5 on December 28, 2011, 04:28:07 PM
Medflight5 -

Can you share the precise feeds - and time slots - you used to piece together your montage? I can't find them in the archives.

Thx.

KEWR New York Departure and NY Appch (Liberty West/South)
Audio was compiled from the 0930L (1430Z) and 1000L (1500Z) feeds from both.

His initial contact with ATC is at 09:51:49L (14:51:49Z)
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: phaques on December 28, 2011, 06:57:59 PM
Thanks - I found them all. First contact is with NY Departure at about 0949 as he is checks in after the handoff from tower at 800 feet.

A question: What is the normal climb performance of a TBM700 and how much does it normally deteriorate as the plane climbs into the low to mid teens? The Flightaware track log shows his airspeed and rate of climb dropping off precipitously as he climbs past 13,000ft, but I wonder how much the change might be due to normal performance changes? In the King Air E90, climb airspeed drops from 150kts to 130kts as you pass through 10,000 feet - does anyone know if there is a similar rate of change for the TBM?. I'd like to get an idea how much of his declining performance is attributable to ice.

Thanks.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: sykocus on December 29, 2011, 06:53:34 AM
Thanks - I found them all. First contact is with NY Departure at about 0949 as he is checks in after the handoff from tower at 800 feet.

A question: What is the normal climb performance of a TBM700 and how much does it normally deteriorate as the plane climbs into the low to mid teens? The Flightaware track log shows his airspeed and rate of climb dropping off precipitously as he climbs past 13,000ft, but I wonder how much the change might be due to normal performance changes? In the King Air E90, climb airspeed drops from 150kts to 130kts as you pass through 10,000 feet - does anyone know if there is a similar rate of change for the TBM?. I'd like to get an idea how much of his declining performance is attributable to ice.

Thanks.
Don't put too much weight on the speed from flightaware. That's the ground speed from radar not the plane's airspeed.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: rduke007 on December 29, 2011, 03:28:17 PM
Groundspeed would be directly related to airspeed and winds, and winds on that day should have produced an increase, so the log is a "tell" in my opinion.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: MikeNYC on December 29, 2011, 05:12:13 PM
rduke, but the aircraft as it climbs will encounter different winds aloft at various altitudes which will all affect the groundspeed differently.
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: rduke007 on December 31, 2011, 05:32:44 PM
This was discussed on Bill Waldock's Facebook page, and winds aloft for the time in question should have produced an increase in groundspeed as the aircraft turned southwest during the climb. Waldock is a recognized expert, and often sought after as an expert witness during litigation. This doesn't make his facebook friends automatically correct, but what I recall reading seemed to be based on accurate data. A lot of those folk are people who studied with Bill as their professor at Embry-Riddle, in the crash lab at the Prescott, AZ campus (where I graduated in 1990.)
Airspeed can be extrapolated from pressure & temperature records,as well as wind vectors, and my opinion, having seen the chart, is that the accident aircraft lost airspeed and climb rate. This is consistent with an airframe icing scenario. It is quite possible that at higher angle of attack, the ice accreted somewhere it wasn't detected, or could be addressed by the available deicing gear, and that the AP in FPM climb mode could well have held the plane in a smooth climb while slowly reducing airspeed until an aggravated stall occurred. If this was sudden, and unexpected, the loading conditions and the surprise factor could have easily resulted in loss of control, or even a spin. This, of course, is educated speculation on my part, and one possible causation scenario. But regardless of the eventual determination by the board, does this discussion change anything for the readers checklist in how we fly & manage traffic under these conditions?
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: frcabot on April 10, 2014, 03:44:09 PM
http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20111220X20005&key=1

Probably similar to what happened to N702H.

I think the probable cause report is a little unfair. Criticizes him for entering "severe" icing but no severe icing was forecasted and even the pilot himself only reported light icing. That three other flight crews reported severe icing doesn't mean the icing was actually "severe" icing as defined by the FAA, let alone for him at a different time and in a different location, and in a different airplane. The Socata is certified for FIKI, even if it's not for severe icing (AFAIK, the definition of severe icing is that the ice accretes faster than the de-icing system can remove it, so I'm not sure what plane could be certified for "severe" icing). According to the full narrative, the pireps about severe icing were made at 0749, 0808, and 1042. His crash occurred at at about 10:05, well after the 0749 and 0808 pireps had been made (and in different areas), and before the 1042 pirep. Plus, there's no evidence that the ATC controller ever advised him of these pireps other than to remind him about "moderate" icing between 15 and 17K.

Also, says the pilot failed to depart the icing area but that's exactly what the pilot was doing. I sure hope the NTSB never writes a probable cause determination like that in my case.

The perplexing thing about the N731CA accident is that the pilot voluntarily departed VMC to enter known IMC and icing conditions. That's pretty poor judgment. Even if you think your plane is capable of handling moderate icing conditions, why would you ever want to tempt fate?
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: InterpreDemon on April 10, 2014, 04:48:07 PM
"I sure hope the NTSB never writes a probable cause determination like that in my case."

I sure hope the NTSB never has a need to write any probable cause determination in my case... or yours :-)
Title: Re: TBM-700 N731CA crash outside of MMU
Post by: frcabot on April 11, 2014, 11:32:02 PM
"I sure hope the NTSB never writes a probable cause determination like that in my case."

I sure hope the NTSB never has a need to write any probable cause determination in my case... or yours :-)
Touche.