Convair 340 (C-131D) ZS-BRV crash Pretoria, South Africa
As I said in a previous post, its really a torquemeter. The way it measures torque is the outer ringgear of the planetary gear reduction unit has helical splines around it's rim. These fit into helical splines in the nose case of the engine. the reaction to engine torque tend to shift this ring gear backward (Or is it forward?, it's been a while) opposing that axial thrust are a series of hydraulic pistons which operate off engine oil pressure from the nose case scavenge pump. there's some sort of metering mechanism so that the pistons exactly offset the axial thrust of the ring gear, and the actual measurement is of the oil pressure required in the pistons to balance that axial force, the signal from the oil pressure transducer is displayed on the BMEP gauge. As a side note, on other radial engine installations, the torque meter was calibrated in units of "Torque oil pressure" which is a more accurate description of what is actually being measured that BMEP, But again, the units are arbitrary, learn what numbers you should see for what power setting on your engine and it doesn't matter the actual units are.
OAP
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I flew/instructed on the C-131B before I left the Air Force 45 years ago. We operated the C-131's through Albuquerque, NM all year long at much higher density altitudes than this takeoff, so it's certainly within the capabilities of the airplane - it all depends upon the weight, of course. There are a LOT of things that could have happened on this takeoff - none of them good; some of them beyond the pilots' ability to do much of anything. We'll just have to wait and see how good the accident investigation is and what it turns up. Hopefully, the pilots will recover and be able to fill in the blanks.
Last edited by Murexway; 14th Aug 2018 at 23:38.
The date is when this document template was created. It's the format used in all of the SA CAA documents, not the accident date.
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Yeah, this. I said "huh????" when I first saw that date, but it didn't take a lot of advanced thinking to figure out what that date represented.
Bit early to be apportioning blame, chaps?
The investigation has a long way to go and minor anomalies in the preliminary report to clear up. The two flight crew have yet to be interviewed, AFAIK, and the unofficial third man is sadly deceased. With a crew debrief still pending, even if a recording of all cockpit conversations is available from the Go-Pro camera it's quite right that its transcript be withheld at the preliminary report stage.
Right now we can try and work out what may have happened, and what the crew probably did. We may also like to form an opinion, from the unhurried comfort of our armchairs, on what might have been done to mitigate the effects of the failure(s).
The investigation has a long way to go and minor anomalies in the preliminary report to clear up. The two flight crew have yet to be interviewed, AFAIK, and the unofficial third man is sadly deceased. With a crew debrief still pending, even if a recording of all cockpit conversations is available from the Go-Pro camera it's quite right that its transcript be withheld at the preliminary report stage.
Right now we can try and work out what may have happened, and what the crew probably did. We may also like to form an opinion, from the unhurried comfort of our armchairs, on what might have been done to mitigate the effects of the failure(s).
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With regard to the apparent left aileron anomaly, I once picked up a Gulfstream G-I turboprop from a heavy "C" check at a busy, well-known, U.S. maintenance facility that was very familiar with Gulfstreams. During the preflight, we noticed that when the control yokes were turned to the right, the left aileron went up and the right aileron went down (and vice-versa) - that was the end of the day's flying. A left engine fire on takeoff would be a bad time to discover that.
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With regard to the apparent left aileron anomaly, I once picked up a Gulfstream G-I turboprop from a heavy "C" check at a busy, well-known, U.S. maintenance facility that was very familiar with Gulfstreams. During the preflight, we noticed that when the control yokes were turned to the right, the left aileron went up and the right aileron went down (and vice-versa) - that was the end of the day's flying. A left engine fire on takeoff would be a bad time to discover that.
Yes they probably would have crashed immediately after lift off if the ailerons were connected wrong way round. The video of the departure of the a/c that is being discussed, showed normal lateral control after lift off.
I know of a light a/c years ago, with the ailerons reconnected incorrectly, after heavy maintenance.. The company chief pilot was the PF on the test flight and a senior pilot in the RHS. At lift off, the inevitable occurred. The authorities tried to blame the PIC. (Yes they survived) They were unable to make it stick, as the Pre t/o check list in the approved FM stated, " controls full and free". The words. "In the correct sense" we're omitted. That Chief pilot had close to 20k hours stick time. I doubt if he ever used an A/P as the entire fleet was never equipped with them. AG aircraft.
I know of a light a/c years ago, with the ailerons reconnected incorrectly, after heavy maintenance.. The company chief pilot was the PF on the test flight and a senior pilot in the RHS. At lift off, the inevitable occurred. The authorities tried to blame the PIC. (Yes they survived) They were unable to make it stick, as the Pre t/o check list in the approved FM stated, " controls full and free". The words. "In the correct sense" we're omitted. That Chief pilot had close to 20k hours stick time. I doubt if he ever used an A/P as the entire fleet was never equipped with them. AG aircraft.
Last edited by Dan_Brown; 14th Aug 2018 at 21:31.
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If the ailerons were rigged backward on this Convair, they would have crashed immediately upon lifting off. That's what happened in both instances I know of where the ailerons were connected backward. It's extremely unlikely that any pilot would be able to recognize what was going on and have enough time at low level to apply control input opposite everything he'd learned and practiced his entire life.
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Yeah, "would have". That close to the ground there simply isn't enough time or space to figure out why the airplane is rolling uncontrollably despite your aileron inputs. If there was a way to initiate this at altitude, perhaps some good pilots could figure it out and overcome a lifetime of practice and control roll with "backward" inputs. 10 ft off the runway? Not a chance. Your wing is in the ground before you have time to think anything other than " whoa! I'm really rolling left, I need more right aileron. "
Regardless, we have ample video of the takeoff it took off without a wobble in roll. Whatever the cause of the raised aileron in the video, it wasn't from them being rigged backward in Mx.
Regardless, we have ample video of the takeoff it took off without a wobble in roll. Whatever the cause of the raised aileron in the video, it wasn't from them being rigged backward in Mx.
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Who said it was rolling uncontrollably? He had control for quite awhile. But If he needed aileron and it went the wrong way, turn the yoke the other way. Just because previous instances turned out poorly doesn't mean they will all automatically result in an immediate crash.
Last edited by Murexway; 14th Aug 2018 at 21:52.
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Well, obviously on the video from inside the plane in flight, there's some problem with the aileron. I'm just saying that I think it's really unlikely that it was a Mx Reversal of the ailerons prior to takeoff. .
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The C-131 was old and slow, but it was a very comfortable, stable airplane. In 1972-73 when Bendix was developing the first TCAS, we used one with specially calibrated altimeters to run head on passes against a C-135 starting with 2,000 ft. vertical separation, and working our way down to 500 ft. It was an eye opener.
But I digress. Hope both the guys in the hospital do well.
But I digress. Hope both the guys in the hospital do well.
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Disgusted
Bare, I read your comment with utter disgust. How dare you slander these pilots before the investigation is complete. What right do you have to judge and condemn anyone involved in this tragic accident on the basis of a preliminary report? Who knows what this crew were faced with on the day. Controllability issues? Engine shutdown? How would you feel about intentionally destabilizing an aircraft that was maybe marginally controllable - immediately after take off? Gear? These guys know whether the gear has been selected up or not - but perhaps the fire had destroyed the gear indication circuitry. Would that not be cause for confusion and or discussion about the gear position? The fire is clearly evident below the wing and in the LH main gear area. Convairs have a history of Aileron issues associated with engine fires. And tell me Bare, which non normal checklist would you call for? The one titled "Crew Are Struggling to Control Aircraft - Shutdown Engine and Lose Control Totally"? Or would you expect the crew to muster their combined 37000 hrs of experience to try and manage a situation for which there is no checklist or training.Or perhaps you have some magical technique that neither Boeing or Airbus have mastered for dealing with multiple failures? The tragedy of this event is that two people lost there lives. It could have been so much worse. By all means speculate on the cause of this horrific event, but don't you dare condemn two men who have arguably saved the lives of 18 people on board, on the basis of a preliminary report.
Hopefully, the pilots will recover and be able to fill in the blanks
Post-Traumatic Amnesia - Memory Disorders - The Human Memory
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WFD post 358. I would go the engine shutdown and fire checklist from memory items close cowl flaps while on the way to land empty in about a 3 seconds pattern as it is an out of heavy maintenance test flight with nil pax/weight....... Is this answer ok, but Im not an Australian top gun so might be a bit simple.
OH I would have run the engines up with the LAME looking from the outside shutdown checked for leaks restarted etc before he jumped aboard rather than " started the left engine once the LAME was onboard per report ".
OH I would have run the engines up with the LAME looking from the outside shutdown checked for leaks restarted etc before he jumped aboard rather than " started the left engine once the LAME was onboard per report ".
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None of us know what was really going on in that cockpit. We can speculate all we want, but let's wait a bit before we castigate our fellow professional airmen, who are still in the hospital.
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Is this the same HARS crew that ferried the PBY from Portugal? There was a YT documentary on that which I can no longer find. I was somewhat surprised at the condition that the PBY was ferried with and the relatively cavalier attitude of the crew to potential problems - even to themselves (caveat, I don't know who narrated it).
