Go Back  PPRuNe Forums > PPRuNe Worldwide > The Pacific: General Aviation & Questions
Reload this Page >

Norfolk Island Ditching ATSB Report - ?

The Pacific: General Aviation & Questions The place for students, instructors and charter guys in Oz, NZ and the rest of Oceania.

Norfolk Island Ditching ATSB Report - ?

Old 31st Jul 2016, 01:29
  #861 (permalink)  
 
Join Date: Mar 2005
Location: N/A
Posts: 2,775
I'm not going to go ferreting around for the post, but there was a post by someone familiar with the systems, that the gear would extend as a result of the damage evident in the photo. Gear required hydraulic pressure to hold it in the "up" position, no pressure available sans engines, and hydraulic lines obviously severed by virtue of the missing forward fuselage.
megan is offline  
Old 31st Jul 2016, 01:36
  #862 (permalink)  
 
Join Date: Oct 2014
Location: In my Swag
Posts: 495
Megan, I can understand how the mains "fell' due to no pressure, but don't understand what forced them all the way down and to appear locked.
Eddie Dean is offline  
Old 31st Jul 2016, 03:56
  #863 (permalink)  
 
Join Date: Mar 2005
Location: N/A
Posts: 2,775
Gravity. From one operators training notes
The landing gear is hydraulically actuated and mechanically controlled. The only electrical items related to the gear are the gear indication, warning, squat switch functions, and anti-skid. With loss of electrical power, the gear may be extended normally, but will not retract because of the down lock solenoid. If you are unfortunate enough to have a hydraulic failure, the gear may free fall to the extended position if the fluid trapped in the uplocks leaks out. Prior to a long over water flight, some operators check the uplocks by jacking the airplane, retracting the gear, bleeding off the hydraulic pressure, and letting the aircraft sit for two or three hours to see if the uplocks hold. Israeli Aircraft makes fine airplanes, however, there are a few things that indicate some level of brain damage in one or more members of their design team. This is one of them. The range and speed of the airplane is somewhat more limited with the gear down.

The landing gear is hydraulic. What a surprise! It is powered by the main hydraulic system. The normal extension and retraction of the gear is not dependent upon electrical power, as in many aircraft. The gear handle on the Westwind actually moves a hydraulic valve that operates the gear. Indication and anti-skid protection is all that is lost if an electrical failure occurs after the gear is retracted. If you have an electrical failure prior to retracting the gear, the ground safety solenoid will not let you move the gear handle out of the down position. It does take electrical power to override this. The most likely use for the override would be the failure of a squat switch followed by an engine failure after V1, but prior to gear retraction, as leaving the gear down would result in a substantial loss of climb performance.

Alternate extension of the gear is done by placing the gear handle in the down position, unlatching the emergency gear handle and rotating it 90 degrees aft, and pulling it up to discharge the nitrogen into the down side of the forward main landing gear actuators. The nose wheel is extended by a bungee.

If the main hydraulic system is not providing pressure to the brakes, the brake pedals can be depressed farther by the pilot's feet. This activates the emergency braking system. The emergency brake system takes fluid from a standpipe in the main hydraulic system reservoir. An electric hydraulic pump supplies brake pressure to the aft brake calipers only. There is no anti skid protection when using the emergency brake system. The emergency brake system is what you use to set the parking brake prior to starting engines, as you most likely will not have main system hydraulic pressure until one of your engines is started.
megan is offline  
Old 31st Jul 2016, 04:40
  #864 (permalink)  
 
Join Date: Oct 2014
Location: In my Swag
Posts: 495
That's what happens if the uplocks all leak.
Any idea what happens when the supply is stopped and no uplock leak?
Eddie Dean is offline  
Old 1st Aug 2016, 06:59
  #865 (permalink)  
 
Join Date: Feb 2006
Location: Melbourne
Posts: 1,652
Any idea what happens when the supply is stopped and no uplock leak?
I would assume that the system will always have a degree of pressure loss.

But the premise of the original question is that damage caused by the ditching created a leak, which seems entirely plausible.
Old Akro is offline  
Old 1st Aug 2016, 07:53
  #866 (permalink)  
 
Join Date: Oct 2002
Location: ɐıןɐɹʇsn∀
Posts: 1,963
I would have thought water pressure would beat 'gravity' in this circumstance..
Hempy is offline  
Old 1st Aug 2016, 20:46
  #867 (permalink)  
 
Join Date: Oct 2014
Location: In my Swag
Posts: 495
+1 what Mr Hemp said
Eddie Dean is offline  
Old 2nd Aug 2016, 00:47
  #868 (permalink)  
 
Join Date: Aug 2004
Location: Melbourne, Australia
Posts: 7,298
Hempy, your grasp of hydraulics seems rather tenuous. It's the pressure differential between the two sides of the piston or between inside and outside of a ram that is responsible for the actuating force.

Broken piping = no pressure differential = no force.

water, hydraulic fluid and absolute pressure are irrelevant if there is no pressure differential.

...or did you mean water pressure on the gear doors?
Sunfish is offline  
Old 2nd Aug 2016, 01:40
  #869 (permalink)  
 
Join Date: Feb 2006
Location: Melbourne
Posts: 1,652
I would have thought water pressure would beat 'gravity' in this circumstance..
Depends which way its acting. Its entirely possible that the water flow past the aircraft while it sinks could pull the gear away from the airframe (ie down). Gravity is not the only force which might extend the undercarriage.
Old Akro is offline  
Old 2nd Aug 2016, 11:02
  #870 (permalink)  
 
Join Date: Oct 2002
Location: ɐıןɐɹʇsn∀
Posts: 1,963
It's a dark and stormy night, and you are attempting to land at a remote strip.

Unfortunately, due to a number of circumstances, you are dangerously low on fuel and have no practical alternate.

Fortunately, the runway aligns with an approach over the ocean, but unfortunately the aerodrome is socked in.

You position yourself safely out to sea, configure the aircraft for landing, and commence a descent in order to get below the cloud and become visual.

Unfortunately, you run out of altitude before you find the cloud base*


*This is a fictional account, and any resemblance to any actual persons or events is entirely coincidental.

I'll be interested in reading the CVR transcript.
Hempy is offline  
Old 2nd Aug 2016, 11:32
  #871 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 2,706
I'll be interested in reading the CVR transcript.
I'll be interested to hear a replay of the actual CVR.

The ATSB has been so compromised that I'm not prepared to accept any "transcript" as bearing an accurate semblance to anything.
Lead Balloon is offline  
Old 2nd Aug 2016, 12:46
  #872 (permalink)  
 
Join Date: Aug 2007
Location: sydney
Age: 56
Posts: 356
It's a dark and stormy night, and you are attempting to land at a remote strip.

Unfortunately, due to a number of circumstances, you are dangerously low on fuel and have no practical alternate.

Fortunately, the runway aligns with an approach over the ocean, but unfortunately the aerodrome is socked in.

You position yourself safely out to sea, configure the aircraft for landing, and commence a descent in order to get below the cloud and become visual.

Unfortunately, you run out of altitude before you find the cloud base
Two problems with this fictional account. Firstly, the PIC has been repeatedly requesting the CVR be recovered. Secondly, would not the gear/gear doors be ripped off if down when ditched.
slats11 is offline  
Old 2nd Aug 2016, 12:58
  #873 (permalink)  
 
Join Date: Mar 2005
Location: N/A
Posts: 2,775
Two problems with this fictional account
Only one problem really, it bares no resemblance to what actually happened, as he said, fictional.
megan is offline  
Old 2nd Aug 2016, 23:26
  #874 (permalink)  
 
Join Date: Feb 2006
Location: Melbourne
Posts: 1,652
The ATSB has been so compromised that I'm not prepared to accept any "transcript" as bearing an accurate semblance to anything.
The "Transcript" of recorded radio calls on area frequency for the Bankstown Mojave accident changed from the interim report to the final report.

And have you noticed that recent reports seem to have ceased publishing full transcripts at all??
Old Akro is offline  
Old 29th Sep 2016, 01:31
  #875 (permalink)  
 
Join Date: Oct 2014
Location: In my Swag
Posts: 495
Has there been any further information released about this accident? Nothing new on the ATSB site.
Eddie Dean is offline  
Old 29th Sep 2016, 07:43
  #876 (permalink)  
 
Join Date: Jun 2000
Location: Australia
Posts: 3,845
Years ago, I learned one thing to my cost after an incident at Alice Springs where an Ansett 727 and a DCA F27 were involved. The F27 captain was more or less hung out to dry on the evidence of an ATC transcript. A clerk did the transcription from the tape to paper but wrote what he thought was said on the ATC tape. In fact he guessed what was said and wrote it down.

For example the request by the F27 pilot "Request Airways clearance" while at the holding point at Alice Springs, was transcribed as "Are we clear" There were several similar mistakes by the transcriber which changed the whole context of the event. Moral of the story is that those involved in such incidents should ensure they are permitted to listen to the tapes themselves and not blindly accept the transcribed version.
Centaurus is offline  
Old 29th Sep 2016, 10:02
  #877 (permalink)  
 
Join Date: Jul 2007
Location: BAO
Posts: 209
Well said Centaurus.

Rgds
S28- BE
Section28- BE is offline  
Old 29th Sep 2016, 22:03
  #878 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 2,706
In the ATSB's original report into the ditching of NGA there were, at the very least:

(A) patent errors in what was represented as a transcription of the transmissions to NGA, or

(B) disclosures of patent errors and omissions from transmissions to NGA.
Lead Balloon is offline  
Old 2nd Oct 2016, 00:08
  #879 (permalink)  
 
Join Date: Feb 2012
Location: West of SY OZ
Posts: 69
AND:

(C) Failure to send atsb the Chamber's report by casa, which was highly derogatory of the operations of PelAir [and ultimately REX];

(D) Obfuscated Senate inquiry by atsb for a lengthy period of time [will be attributed to staff cutting and MH370, no doubt]

Last edited by advo-cate; 2nd Oct 2016 at 00:10. Reason: Layout
advo-cate is offline  
Old 4th Oct 2016, 23:51
  #880 (permalink)  
 
Join Date: Feb 2006
Location: Melbourne
Posts: 1,652
The ATSB transcripts of ATC recordings differ between the draft & final reports of the Bankstown Mojave accident. Which really raises questions about the ATSB preparedness to change transcripts to suit the conclusion they want. Transcripts are no longer evident in recent ATSB reports that i have read. They seem to instead to adopting isolated quotes from a transcript.
Old Akro is offline  

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.