Gulfstream IV crash at KBED, 5/31

[Captain_Barfbag 31]

This one happened in my home town.  A G-IV went off the end of RWY 11 on takeoff.  7 souls aboard, no survivors.

 

They found the recorders and they seem to have good data.  They are analyzing them now and information is coming out slowly.

 

Weather was clear, the pilots were experienced, but the plane never left the ground.  Someone said "Rotate," but shortly after that brakes and reversers were applied.  The plane skidded through an antenna and a chain-link fence and stopped abruptly in a stream bed, where it exploded and burned.

 

I've been Googling "Hanscom crash" to get updates

[zmak 331]

If they were at :"rotate" as you say then they could not have aborted safely. Must have been a catastrophic failure perhaps? Awful way to go,RIP

[flybius 3]

I just read in the Boston Globe that max ground speed exceeded 160+ Knots at rotate call. I'm not familiar with the G-IV, but this seems fast to me. I am wondering if a take-off config (flaps, etc,) was to blame.

 

Perhaps someone more familiar with the G-IV can advise...

[Richard Sennett 2,499]

Flew out of that same runway in a lear jet - yah seems way to fast - and they now believe they hit the reversers and leaned on the breaks so something may have gone wrong with control surfaces ? - terrible thing to hear about

[Robert McDonald 167]

God rest their souls.

[Bob Scott 7,721]

From what I've read in the media, the FDR data showed that the G-IV had flaps set at 10 (nonstandard but legal), reached a max speed of 165 Kts and never left the ground.  CVR analysis showed that after the "rotate" call there was mention of a controllability problem (no specifics given).  The acft should have been pretty light with only 4 pax and fuel for a ~1 hr flight.

 

Assuming a reduced thrust takeoff at 10 flaps, just from memory I'd estimate V1/Vr was in the neighborhood of 125 KIAS, and takeoff roll probably close to 3500 ft.  At/after the rotate call, the jet is accelerating rapidly, and eating up over 250 ft per second of runway.  Given ~40 knots of acceleration after Vr until the abort was initiated, I'd estimate ~10 seconds elapsed from the rotate call to the initiation of the abort, so that puts the jet another 2500 ft down the runway at very high speed...165 knots at the 1000 ft remaining marker is a bad place to be.  That said, there was 1000 feet of paved overrun, and another 817 feet of open field until the ditch where the aircraft stopped.  The FDR stopped recording at 100 knots, suggesting the jet only slowed ~65 knots over the ~2800 feet from abort initiation until high-speed impact with the localizer antenna array and/or terrain in the ditch.

 

One important missing data point is the ground spoilers--the jet may well have been traveling fast enough at the time of abort to generate enough lift to get the "nutcracker" system (Gulfstream parlance for the weight-on-wheels switches) out of ground mode, in which case the ground spoilers would not have auto-deployed when the throttles were retarded to idle.  If the ground spoilers failed to deploy automatically, and the pilot did not immediately deploy them manually, the lack of weight on the wheels at that speed would have massively reduced the braking effectiveness during the initial phase of the abort.  That might explain what appears to be poor braking performance during the abort.

 

I'm more than a little bit interested to hear the "rest of the story" here, and it seems certain there are a lot more facts bearing on this accident yet to be discovered.

 

Regards

[Captain_Barfbag 31]

Thanks, Bob.  Since you know about these things...

 

I had a thought that auto-brake, auto-thrust-reversers and auto-spoilers might have been set on takeoff, which I assume would be wrong.  Then, the plane gained a few feet of altitude and came back down, activating the "nutcrackers" and applying one or more of those.  Is that even possible?

[MDF86 123]

RIP. Sad to hear of any fellow aviation lovers losing their lives.

[airman17 2]

Having followed those approach lights myself countless times it's hard to see something like this happen so close to home. Prayers to the families.

[JRBarrett 3,076]

Thanks, Bob. Since you know about these things...

 

I had a thought that auto-brake, auto-thrust-reversers and auto-spoilers might have been set on takeoff, which I assume would be wrong. Then, the plane gained a few feet of altitude and came back down, activating the "nutcrackers" and applying one or more of those. Is that even possible?

The GIV does not have autobrakes, nor automatic thrust reverser deployment. The ground spoilers would be set to auto deploy by the selection of of a switch on the center console - this is normally done while turning onto the runway to begin the takeoff roll - the auto-deploy feature would be switched off once safely airborne, and re-enabled during the final approach segment before landing.

 

But, as Bob mentioned, if the wings developed enough lift to switch the WOW system to air mode, the spoilers would not have auto-deployed.

 

I don't fly the GIV, but do have several years experience maintaining them. Clearly something went very wrong in the pitch control system, but it would be impossible to say what may have happened at this point.

 

The design has been in service for 25 years, with millions of safe flight hours logged - and I don't believe anything like this has ever happened before.

[NGXfanatic 85]

This incident is all over my local news because the new co-owner of my local city paper, Lewis Katz, was on the ill fated flight.  A real gem of a man, as my father says, he was one of the very few of the super rich who really used his money and influence to help mankind, often anonymously. 

 

The first thing I thought about when I first heard about the crash was if a VIP was onboard.   I live under the a STAR to KTEB, and I often think about who may be on board the biz jets gliding overhead at 18000ft. 

 

This was a very tragic event for all involved, and very unusual for such a reliable aircraft. 

[Captain_Barfbag 31]

The NTSB has released a preliminary report.

 

"The Globe reports that a preliminary report from NTSB shows that as the plane took off, the controls were in “gust lock” position, which secures the rudder and elevator to keep the plane safe from damage while parked."

 

Here is the full story from the Boston Globe site: 

http://www.boston.com/news/local/massachusetts/2014/06/13/ntsb-confirms-hanscom-crash-came-after-rejected-takeoff/igIl1qI4OgHIrouLDrcm4K/story.html

 

So, it looks like a glaring case of the crew failing to follow pre-flight check procedures.

[3-2-1-Now 126]

 

 

I had a thought that auto-brake, auto-thrust-reversers and auto-spoilers might have been set on takeoff, which I assume would be wrong.

Read Bob's post again. He sets out what *maybe* happened.

 

*IF* it is true the gust lock was still in at takeoff, very serious questions need asking.

 

The final report will make for very interesting reading.

 

Best regards,

Robin.

[n4gix 4,947]

The article in the "Globe" seems a bit incomplete, as the actual NTSB preliminary report* states:

 

"The FDR data revealed the elevator control surface position during the taxi and takeoff was consistent with its position if the gust lock was engaged. The gust lock handle, located on the right side of the control pedestal, was found in the forward (OFF) position, and the elevator gust lock latch was found not engaged."

Read the last sentence carefully. Although the "gust lock was found not engaged" nonetheless due to the lack of a control movement check, the actual "unlocking" was not confirmed.

 

Furthermore, the gust lock system on the GIV will also restrict power lever movement to ~6% thrust, which is just enough for taxiing. There is no possible way they could have reached 165 kias were that gust lock still engaged.

 

* See: http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20100217X24906

[3-2-1-Now 126]

the elevator control surface position during the taxi and takeoff was consistent with its position *** if *** the gust lock was engaged

 

It only raises more questions.

 

I never under-estimate the force crews will use to do things that shouldn't be possible/should have them questioning serious problems, but apparently don't (hence why we read these accident reports).

 

I'll never forget the unofficial conclusion of the F100 crash (reverser deployment in flight). It was supposed one of the crew members wedged himself between the cockpit bulkhead and the thrust lever to force it back to cruise position, breaking the reverser unlock linkage in the process. End result was nearly full power against a deployed thrust reverser, which resulted in the crash.

 

Some crew actions can never be adequately explained.

 

Best regards,

Robin.