Go Back  PPRuNe Forums > Aircrew Forums > Biz Jets, Ag Flying, GA etc.
Reload this Page >

HS 125 reported crashed in Akron

Biz Jets, Ag Flying, GA etc. The place for discussion of issues related to corporate, Ag and GA aviation. If you're a professional pilot and don't fly for the airlines then try here.

HS 125 reported crashed in Akron

Old 13th Nov 2015, 10:39
  #41 (permalink)  
 
Join Date: Aug 2000
Location: UK
Posts: 234
My memory may be a bit faulty but I carried out several 700B to 700A conversions, and A to B's back in the 80's and cannot remember any modifications to the wing. There used to be a SB to carry out the work but I can no longer access it.

Regarding post #26 "appears to be mechanical." I cannot recall any fatal Hawker accident caused by mechanical failure over the last 30 years, although they have had the usual undercarriage not coming down over the years and the odd engine blown off by a missile. May be somebody could correct me?

Mike Echo

Last edited by Mike Echo; 13th Nov 2015 at 11:30.
Mike Echo is offline  
Old 13th Nov 2015, 14:03
  #42 (permalink)  
 
Join Date: Apr 2009
Location: On the Beach
Posts: 3,221
Apartment house. 60' (approximately) power lines across the street:
aterpster is offline  
Old 14th Nov 2015, 04:27
  #43 (permalink)  
 
Join Date: Apr 2008
Location: SFO
Posts: 21
I think it's actually the building to the left of this one. There's three, all of which are nearly identical. You can see on the video of when they're extinguishing the fire.

Not that it matters of course.

The one news story I noticed was of the tenant, a fellow of around 30-35 years old, who left his unit and drove down the street to buy some 'Hot Pockets' (Processed pastries), returning home 20 minutes later to find his apartment in a heap of flames. Just chance.

Initially, seeing the weather and the approach, it was easy to dismiss this one as pilot error - getting a sneak peak below minimums. But upon seeing the video, it seems there might be more to it. No FDR, but a poor quality CVR. I hope if it was mechanical, that the pilots can be vindicated. An unfortunate set of circumstances nevertheless.
simon001 is offline  
Old 14th Nov 2015, 10:16
  #44 (permalink)  
 
Join Date: Dec 2002
Location: Essex, England
Posts: 91
Stalling the Hawker

I am not suggesting that the aircraft in question was stalled or not, but while the topic has moved to stall tests I add this;

There must be hundreds if not thousands of Hawker pilots like me who have done the post maintenance stall tests regularly following removal/inspection of LE anti icing panels.

The auto pilot should NOT be engaged, and crucially following the stall there should be NO attempt to recover with minimum loss of height . (Like we were all previously required to do in the sim, but which has now, sensibly, been dropped from the training).

If the autopilot IS engaged when the aircraft stalls - it will disengage of its own accord anyway.

As soon as the back pressure is released (and believe me there is a LOT needed to get it to stall) and thrust is added, the aircraft should be allowed to descend and accelerate before attempting to regain altitude - bearing in mind that you should have a LOT of space between you and the ground.

There is a requirement to calculate the expected IAS for activation of the stick shaker and stall, but from memory Hawker do not provide a table that gives this data for 17,000 feet that was mentioned in the highlighted AIN article. (IAS stall speed increases with altitude, as we all know).

Sometimes one wing or the other may drop violently, but I never had a Hawker enter a fully developed spin. My experience is that even a violent wing drop is easily contained as soon as the back pressure is released and both wings are fully unstalled. From memory (I'm no longer on the Hawker) any wing drop of more than 10 to 15 degrees requires rectification and re-testing before release to service.
sooty3694 is offline  
Old 14th Nov 2015, 12:52
  #45 (permalink)  
 
Join Date: Apr 2009
Location: On the Beach
Posts: 3,221
Simon 001:
I think it's actually the building to the left of this one. There's three, all of which are nearly identical. You can see on the video of when they're extinguishing the fire.
I used the street address published in the Akron newspaper the day after the accident.
aterpster is offline  
Old 14th Nov 2015, 16:19
  #46 (permalink)  
 
Join Date: Dec 2010
Location: UK
Age: 63
Posts: 79
the Hatfield design view was that they would only improve a bad wing – "Hatfield does not design bad wings"
So Hatfield didn't design the Mosquito with its bad stall (according to Winkle Brown), or the Comet 1 with its ground stall, or the DH110 with its flutter, or the Trident which went through half a dozen wingtip designs in drag reduction attempts before the wings were finally clipped to preserve fatigue life?

Preserve us from designers' hubris.
Iron Duck is offline  
Old 15th Nov 2015, 06:58
  #47 (permalink)  
 
Join Date: Jul 2006
Location: Idlewild
Posts: 115
IAS stall speed increases with altitude
That should be TAS
uncle8 is offline  
Old 15th Nov 2015, 10:06
  #48 (permalink)  
 
Join Date: Dec 2002
Location: UK
Posts: 1,847
Sooty,
With fading memory the AP should disengage at stick shake, not at ‘stall’ (stick push). The use of the AP (autotrim) at low speed in the 125 may be of greater importance because of the ‘short coupled’ design. This implies that more tail up-trim could be applied which detracts from stall recovery.
Planned stall tests should limit the start trim condition to 1.3 Vs (similar to Vref, i.e. a margin ~ 30kts), stick shake is nearer 1.1 VS (~ 10kts). The difference is like having to fly normally with the aircraft out of trim by 20 kts.

Iron … its not for me to defend a reputation, but inaccuracy demands comment – pickled not preservation.
In the heat of war, having building a wooded aircraft with higher capability than most others, who worries about the sensitivity of a stall.
Ground 'stalls' are linked to the aircraft configuration – tail arm and elevator effectiveness.
The DH110 was a structural failure (rolling g), not flutter.
The Trident is a classic example as why the operator should not be allowed to ‘design’ an aircraft.
safetypee is offline  
Old 15th Nov 2015, 10:26
  #49 (permalink)  
 
Join Date: Dec 2002
Location: Essex, England
Posts: 91
Uncle 8:

You are correct; for the same IAS, TAS does increase with altitude.

Unconnected with this though it is a fact that the indicated 1 G stall speed at altitude is greater than that at SL.
sooty3694 is offline  
Old 15th Nov 2015, 16:30
  #50 (permalink)  
 
Join Date: Jan 2008
Location: Torquay UK
Age: 91
Posts: 163
Originally Posted by safetypee View Post
Sooty,
With fading memory the AP should disengage at stick shake, not at ‘stall’ (stick push). The use of the AP (autotrim) at low speed in the 125 may be of greater importance because of the ‘short coupled’ design. This implies that more tail up-trim could be applied which detracts from stall recovery.
Planned stall tests should limit the start trim condition to 1.3 Vs (similar to Vref, i.e. a margin ~ 30kts), stick shake is nearer 1.1 VS (~ 10kts). The difference is like having to fly normally with the aircraft out of trim by 20 kts.

Iron … its not for me to defend a reputation, but inaccuracy demands comment – pickled not preservation.
In the heat of war, having building a wooded aircraft with higher capability than most others, who worries about the sensitivity of a stall.
Ground 'stalls' are linked to the aircraft configuration – tail arm and elevator effectiveness.
The DH110 was a structural failure (rolling g), not flutter.
The Trident is a classic example as why the operator should not be allowed to ‘design’ an aircraft.
Sorry to go off at a small tangent. I remember seeing clear slo mo images of DH110 Control surfaces detached and flying a foot or two behind the aircraft-- interpreted as flutter
wilyflier is offline  
Old 16th Nov 2015, 11:44
  #51 (permalink)  
 
Join Date: Jun 2006
Location: Canada
Posts: 1,309
Iron Duck, you forgot about the 87A model Hornet Moth with its tip stalling in the landing flare, followed by a sharp wing drop resulting in an impresive cartwheel acros the airfield, DH did of course replace {free of charge it is said} with " square wings". to solve the problem, however this made the aileron controll marginal to say the least, also the chief test pilot, Hubert Broard was fired for not finding this fault in the test program. I happen to own a "Hornet", its handling is quite "entertaining" to say the least, but this is what makes it" interesting "to fly, lots of fun!
clunckdriver is offline  
Old 16th Nov 2015, 13:44
  #52 (permalink)  
 
Join Date: Nov 2015
Location: Hinckley, OH
Posts: 3
This was sent to me by a friend. Sorry I don't know the source. Images did not reproduce and I don't see how to attach to this post. Full post with images should be here: https://drive.google.com/open?id=0B9...1JLSDMzUHhZVzg

------------------------------------

As a pilot that has flown in and out of the Akron Fulton airport hundreds of times and utilized the very same instrument approach procedure that was being used by the Hawker jet, here is My assessment of what happened to the plane that crashed at Akron Fulton.

I've been looking at all sorts of evidence available online. I've looked at the FlightAware radar tracks. The coordinates, the altitude, the airspeed, the flight path. I have listened to the recordings of the air-traffic control exchanges with the pilots which indicate nothing remarkable. I have made overlays of the flight path and transferred coordinates onto the approach plates and the aviation navigation charts.

Here's what I have concluded based on everything I can see. Understand that I am relying on data from sources I believe to be accurate and also that I presume I have correctly interpreted.

All the information gleaned indicates the plane was flying normally and was vectored by Akron-Canton approach control to intercept the final approach course for the localizer 25 approach into Akron Fulton airport. The radar coordinates log shows that at 2:48 PM as they turned west to intercept, they were at the proper intercept altitude of 3000 feet for the localizer final approach course. They were still traveling pretty quickly at this point (at 180 knots). Vref in a Hawker is 108 knots.
image1.PNG

You can see above that as they turned Southwest to align themselves with the localizer approach course they were pretty much leveled and beginning to reduce their excess airspeed. Note the trend with from 2:49-2:50 pm with the ground speed slowing from 178 mph down to 146 mph. Of course if you are trying to slow down significantly you normally cannot begin the descent at the same time as you're trying to bleed off (slow) the airspeed as the two dynamics counter one another. The last line on the above chart shows that they were still at 2800 feet and slowed to 146 mph. This would be Vref + 20 for a Hawker or right about where they'd want to be at that point.

Notably, when you plot the latitude and longitude coordinates shown in that last line of position track onto the aviation chart, that is exactly at the point of the localizer outer marker beacon (LOM) but they're still a bit high at 2,800 feet. Referring to the approach plate, you ideally want to be at 2,300 feet by the time you reach the localizer outer marker. With that extra 500 feet of altitude, instead of just descending at a more stabilized rate of 500 ft./m, the pilots were faced with losing 1,300 feet of altitude to get down to the minimum permitted descent altitude of 1,540 feet and they now only had about 3 miles in which to accomplish that descent.

Considering the speed at which they were flying, they'd had to have reduce power rather drastically (to high idle) and descend at about 1,000 + feet/min to get down to the MDA of 1,540 in the time and distance available. In fact, they reached the impact point in just 1.8 miles so they lost 1800 feet of altitude in less than one minute meaning my guess that they were descending very quickly is probably an accurate one - probably 1500 to 1800 ft./m descent over that short stretch .

Incidentally, an Akron-Canton air traffic control communication that occurred just seconds after the accident pilots made their frequency change to Akron Fulton read off weather conditions to another pilot of 400 feet overcast, 1-1/2 miles in rain. So even when our subject plane reached the permitted MDA of 1540 feet MSL it would still have been in the clouds at about 500 feet above the ground. Descending so rapidly and being consumed with looking outside the cockpit for Visual ground contact probably created a recipe for disaster.

So they inadvertently descended right down through the MDA, break out of the clouds at just 400 feet above the ground and they're descending at 1,500 fpm with the power throttled way back. This leaves virtually no time to pull up or spool up the engine power to level off. In just 12 seconds you drop 300 feet.

Result -- the plane flies right into the ground in essentially "controlled" flight. The house which which they impacted lies exactly under the extended centerline of the runway, which would seem to indicate the plane was tracking the approach path very precisely from a horizontal standpoint but there is no vertical electronic guidance for altitude on this approach. The altitude must be carefully managed by the pilots on this type of instrument approach and that needed to start well before the outer marker. Having not done so, the pilots then needed to descend at an abnormally high rate resulting in a non-stabilized approach. Particularly Bad news when weather is at or below minimums.

The FlightAware plot below shows the flight path of the plane (in blue line) and that their turn in to the final approach course occurred sufficiently far enough out to the East (approximately at the Akron VOR) to allow getting the plane properly stabilized from an altitude and airspeed perspective.

image3.PNG


Here are the Akron Fulton weather observations 10 minutes before and 10 minutes after the crash. At best the ceiling was 500 feet and at worst it was 400 feet which put the conditions right at or below the permitted minimums for the instrument approach that was being attempted

image4.PNG

Here is an excerpt from the instrument approach plate diagram for the approach that was being flown. Note the recommended altitude of 2300 feet at the localizer outer marker (LOM). Also note the minimum descent altitude of 1540 feet

image5.PNG
Piper J3 is offline  
Old 16th Nov 2015, 16:05
  #53 (permalink)  
 
Join Date: Nov 2015
Location: Oklahoma City, OK
Posts: 1
With that extra 500 feet of altitude, instead of just descending at a more stabilized rate of 500 ft./m, the pilots were faced with losing 1,300 feet of altitude to get down to the minimum permitted descent altitude of 1,540 feet and they now only had about 3 miles in which to accomplish that descent.

Considering the speed at which they were flying, they'd had to have reduce power rather drastically (to high idle) and descend at about 1,000 + feet/min to get down to the MDA of 1,540 in the time and distance available. In fact, they reached the impact point in just 1.8 miles so they lost 1800 feet of altitude in less than one minute meaning my guess that they were descending very quickly is probably an accurate one - probably 1500 to 1800 ft./m descent over that short stretch .
Simuflite trains to use a 1,200 fpm rate of descent between the FAF and MDA in the Hawker 700. The configuration would be flaps 25, speed ref +20. The training material doesn't specify a power setting, but power is not at idle.
yzpilot is offline  
Old 17th Nov 2015, 02:12
  #54 (permalink)  
 
Join Date: Jul 2013
Location: Pittsburgh
Posts: 129
Did we not see that they were left wing down, nearly vertical at impact? I.e. Certainly not wings level at ground impact.
Was ther e prior impact which flicked the aircraft wing down?
Smott999 is offline  
Old 19th Nov 2015, 23:40
  #55 (permalink)  
 
Join Date: Aug 2013
Location: South Alabama
Age: 69
Posts: 321
Video

I went back and looked at the video from the construction company several times.

To me, it does not look like they were vertical or in a bank.

It appears they were moving fast, and fairly level, which would go along with the comment that they started out high and fast.

We don't know of the VNAV capabilty of this aircraft, so one might assume they were using the "dive and drive" technique.

Just another observation.

RGDS

OBD
Old Boeing Driver is offline  
Old 20th Nov 2015, 00:01
  #56 (permalink)  
 
Join Date: Jul 2004
Location: Dunnunda
Age: 58
Posts: 130
Sorry OBD but having stopped that video a few times just prior to impact, the wings appear vertical to me - cabin towards the camera.

I concur that when the aircraft was behind the trees it appeared to have a reasonably level wing attitude which suggests that impact with trees or power lines may have flicked the aircraft over.

AS
Art Smass is offline  
Old 20th Nov 2015, 12:44
  #57 (permalink)  
 
Join Date: Aug 2013
Location: South Alabama
Age: 69
Posts: 321
@ Art

Thanks. I do not have that capability, so just watched through it several times.

Looks like they were moving pretty fast.

RGDS

OBD
Old Boeing Driver is offline  
Old 18th Oct 2016, 18:59
  #58 (permalink)  
 
Join Date: Feb 2006
Location: USA
Posts: 389
Pathetic... just pathetic

FAA oversight of Part 135 operators and Part 142 trainers turns out to be not worth very much...

NTSB Docket

Group Chairman's Factual

On the subject of training for CDFA at CAE/Simuflite:
Execuflight training guidance did not contain language for CDFA on non-precision approaches. While several CAE Simuflite instructors indicated they may teach CDFA as a technique, there was no formal instruction on CDFA.
Zeffy is offline  
Old 18th Oct 2016, 22:32
  #59 (permalink)  
 
Join Date: Jun 2005
Location: USA
Posts: 945
Reading the CVR transcript made it pretty clear to me what occurred. They conducted themselves quite differently than one must in order to pass training. You train like you're supposed to fly. Unfortunately not everyone flies in the manner they did when they were trained and checked.
westhawk is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.