Jump to content

Polish Hercules Mishap


airnav
 Share

Recommended Posts

  • Replies 73
  • Created
  • Last Reply

Top Posters In This Topic

Take a look at the external tank and think of the damage that would be caused by a portion of the prop or boot or lockfoam or spinner...??? flying off in a trajectory that would impact the external tank. Just a thought... Also the Main landing gear door would be on the same vector...(with airflow taken into account....

Left wing damage looks like the panels just scraped up the side of the aircraft and impacted the fillet at the wing root....

Not much impact damage that I can see (from trees or other stationary objects)

Elevator is missing with no leading edge damage or underwing damage...pure overstress and failure?

Hope we can get more information LOTS MORE.... I would like to hear about the control imputs they use. We teach a Boost out approach but.... COME ON!!!

one word LUCK!

Link to comment
Share on other sites

Consider it as a rumor, but because its public, I can put it here. According to some news, the primary cause of the 1299 mishap were the attitude indicators - they were not giving the same indications.

Is it possible or just a news b.s.?

How the C-130 autopilot would react in such case?

Oberon

Link to comment
Share on other sites

Should not be an issue the autopilot can only be coupled to one attitude source. If the attitude source or power source fails there are several "warning lights and flags" that would be displayed to the flight crew.

Alternate sources (of both) can be selected but there are steps to be taken when switching to the new source.

The autopilot will follow the source selected if the failure is not a hard failure that would trip the "GYRO" flag and the autopilot fail light.

So its hard to say what could have happened we'll just have to wait!

Good thing is the aircraft was on loan from the USAF so I'am sure the AF will put out a 1000 page report and then blame the relays in the secondary AC system......

Link to comment
Share on other sites

We've had some "issues" with the C130 ADIs sticking at 20 and 30 degree roll indications. It been a subject during the PIWG and the SSG.

There have been dual failures in the past too. This is purely mechanical in the ADI, so any source feeding the A/P would be OK, and as stated, the A/P would have tripped off with any flags coming into view.

Link to comment
Share on other sites

Consider it as a rumor, but because its public, I can put it here. According to some news, the primary cause of the 1299 mishap were the attitude indicators - they were not giving the same indications.

Is it possible or just a news b.s.?

Yes. The primary source for the attitude indication is a gyro, MD-1 gyro in most cases. The MD-1 gyro is a gyro that has gimbal torquers attached to the parts that hold the spinning mass (gyro). That gyro has fast and slow torquers for erection. The Rate Transmitter gyro (Not to be confused with the Rate-Of-Turn gyro.) is a smaller gyro that provides 'turn rate cut-out'. Turn Rate Cut-out basically 'disconnects power to the slow torquer motors on the gimbal while the aircraft is in turns. That prevents erection of the gyro to the case while the gyro case is not level.

Here goes a lot of IFing: If the Rate Transmitter gyro internal contacts were stuck in 'cut-out' (and that does happen occasionally) the MD-1 gyro will continue to spin at the same speed, thus not displaying a big red OFF flag on the indicator, but the mass will precess and the indication will roll slowly off to one side or the other at a rate that is barley noticeable.

Improper power to the gyro could also cause the gyro to spin at a slower rate than normal, but still not show a flag and cause incorrect information to be displayed, but that's a bit rarer.

Now, having said that, the pilot and copilot have the ability to use other sources for their attitude information. If one indication seemed to look inaccurate, they should have switched sources to determine which source was showing bad information.

How the C-130 autopilot would react in such case?

Oberon

Ah, autopilot... In a normal flight configuration the vertical reference gyro used to maintain straight and level flight was a K-6A gyro in the E-4 Autopilot system. In the FD-109/AP-105 system, I'm pretty sure the the MD-1 was used for vertical reference. I'll have to do a little research on the digital autopilot vertical reference source.

UPDATE: The FD-109/AP-105 system uses the MD-1 for vertical reference and in the AN/AYW-1(V)1 autopilot it's the VG-1 or INS. (We'll leave gunboats out of this.)

To answer your question, if the autopilot was using a bad source for vertical reference such as the MD-1 gyro and the pilot was using VG as opposed to INS, the autopilot would follow the source, if it was slowly rolling the ADI and autopilot would be doing the same thing.

I'm sure I missed something in the autopilot portion and I don't have the books in front of me, so someone correct what I said wherever it's needed.

328X1

UPDATE: A lot depends on who had what selected/coupled as a nav aid, so there are a lot of possible scenarios.

Edited by 325X1
Updated Information
Link to comment
Share on other sites

  • 2 weeks later...

I can see the autopilot as a partial, possible cause, but cant see it as the total cause.

Many many moons ago, while flying over the Atlantic to Aviano, 62-1857 decided to go from FL220 to about 5,000 AGL in about ten seconds or so (man I was pissed, dying when I only had 70 flight hours or so).

I was happy asleep on top of the ABCCC capsule when the next thing I know I am stuck in the control cables, then some time later I smashed back down into the capsule with about 600 lbs of force - OWWWW (at least I didn't have it as bad as Bob Mayer, CC, when he came back down he missed the capsule - big thump). Seems like the AC and Nav were back in the capsule making some sandwiches and just the other FE and the idiot CP (some griz adams guy, don't remember his real first name) were up front.

The AP was engaged and the copilot did something with the controls that made it just totally freak out, next thing you know the G-meter is maxed out both ways and fuel is running out of the flap tracks. Was rather pissed when they only wrote up an AP error and no mention of Over G:mad: But I was a freshly minted FE so I didn't get a say (I never let that happen again though).

Now looking at that Polish incident, I would be hard pressed to see that amount of damage strictly from an autopilot function. The speed and maneuver must have been HUGE to cause that kind of damage and the crew would have had to sit there and do nothing for many many seconds for it to get to that point. The only reason the AP hosed us on 1857 was the Pilots seat cushion was stuck in the co-pilots face and the moron was more worried about that than reacting to the dive.

Dan

Link to comment
Share on other sites

Tiny's got that one! If you move the flight control you would override the AP and it would disconnect... If the CP made an input to the AP controller IE: turn RT and it stayed in a turn and the rudder did not help... could be big trouble... might have been a attitude reference failure that would cause the AP to follow a bad reference....depends on the failure.. switch the inverter to the DC position with INS selected as the ATT source and you can see the effects on the ADI which may (most likely) be sensed by the AP and....HANG ON.

Link to comment
Share on other sites

What J heard from my good informed friend, engineers read a flight recorder and a speed was 1009 km/h and 5.8 g

According to my calculations that's 544.8 knots 627 mph. At what speed should the wing off light illuminate?

Hey! Maybe the problem with the indicators was that the A/S ind was reading too high. :P

325X1

Link to comment
Share on other sites

According to my calculations that's 544.8 knots 627 mph. At what speed should the wing off light illuminate?

Hey! Maybe the problem with the indicators was that the A/S ind was reading too high. :P

325X1

A tanker is good to 460 knots. That's what 106 did when it rolled over back in 2004 with IFR pods.

We had rolled over at least twice, lost 9,000 feet of altitude at a maximum rate of descent of 29,000 fpm, probably exceeded four positive and three negative G's (aircraft limits are +3 and -1), and reached a maximum speed of almost 460 knots.

The data pallet, installed in the cargo compartment to record our flight-test data, had recorded invaluable performance data from which we could reconstruct our flight profile. A month later, after extensive inspections and minor repairs, we returned to Huntington and flew our aircraft home.

http://safetycenter.navy.mil/media/approach/issues/sepoct06/The_Wild_Ride_of_106.htm

Link to comment
Share on other sites

When 69-6572 did their yankin' and bankin' during Desert Storm the G-meter showed +4 and -1 1/2 when I went out to FCF it.

Reason for the FCF was combination of engine and prop changes that were required.

Funny thing is after that it took less rudder trim for it to fly straight than before the acrobatics. There was a story about that plane being bent in Viet Nam, so we started saying that they bent it back.

Link to comment
Share on other sites

  • 2 weeks later...

Today I received several more photos regarding the damage, more than the original four. Infact I have 19 additional shots. The left wing's fuel tank nose is flattened against the mid-tank divider wall. The pics I received are numbered 011 to 034, telling me there are more out there but not being released...hmmmm... and four of those you've already seen. Al and I were in the desert together when 69-6572 had its encounter with over G conditions and this is very plausible. That the crew overstressed the aircraft in clouds loosing both ADI's and lost of situational and aircraft control. The other pics show major damage to both wing roots, aft wing root panels, hindge arms, etc.

http://s391.photobucket.com/albums/oo356/edrz01/Aircraft%20Mishaps/Polish%20C-130E%20Mishap/

Edited by edrz01
Link is incorrectly placed.
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share


×
×
  • Create New...