Air Crash Investigation TV next week. Boeing 737 NDB approach goes wrong.
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SOPS, Yes you are correct. I should have mentioned that as well for the older model 777 that still has ADFs.
I'm not sure what 'V's aircraft will have fitted as I wasn't commenting on theirs however many CADs now will approve aircraft without ADFs and many countries are rapidly withdrawing NDBs.
IMHO not before time having a few years back in a 74 classic been required to backtrack an NDB to a procedure turn to intercept an ILS in a non radar enviroment. 4000' wind of 240/80k and a healthy split of 30 odd degrees between both ADFs. Cannot be done there now...NDBs removed and RNAV approach installed along with the remaining ILS.
I'm not sure what 'V's aircraft will have fitted as I wasn't commenting on theirs however many CADs now will approve aircraft without ADFs and many countries are rapidly withdrawing NDBs.
IMHO not before time having a few years back in a 74 classic been required to backtrack an NDB to a procedure turn to intercept an ILS in a non radar enviroment. 4000' wind of 240/80k and a healthy split of 30 odd degrees between both ADFs. Cannot be done there now...NDBs removed and RNAV approach installed along with the remaining ILS.
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Get with the times. Unfortunately not everyone has that chance and still uses NDBs which will be around for a while longer yet. If you've got'em know how to use them, if you aint got'em then dont worry.
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Getting back to the original post. The USAF prang at Dubrovnik was caused by several factors. They were attempting to conduct a twin locator approach in an airplane that had only one ADF receiver installed. They had no prior experience of this approach or at this airport. The weather was below minima at the time, but they were carrying a high-powered delegation so there was great pressure on the crew to deliver . The Jeppesen approach minima had been calculated to a lower standard than that required by the USAF, but the crew did not have the USAF minima. USAF Command knew all about it but convienently did not advise crews operating to Dubrovnik of this. Their excuse was that other crews had managed to fly there OK in the past (and indeed on the day of this accident a more experienced crew had scraped in). And although they can not prove it because the airplane had no CVR (not required by USAF at the time) they believe that the crew may have decided to rely on INS positioning for the final tracking, even though they had been airborne for considerable time and had had numerous tracking changes with large changes of heading and no INS updates. This was pre-GPS days and for those of you who remember INS, you simply can not use it as sole means of navigation for precision tracking to a runway. So all the above is the classic Swiss Cheese example they use in safety seminars. The least guilty party in this sad event appears to have been the crew allthough of course in crude terms pilot error contributed. As it will ever be the case when adequate training and proper resources are not provided by the operator.
For as long as there is the potential for multiple failures and diversions to emergency aifields, at least one raw data, hand flown, engine out instrument approach to circle should be part of every annual test. Using what ever is the most degraded navigation equipment in the airplane. If the ADF receiver disappears, that would be the VOR, but without the benefit of the HSI. This requires the same level of interpretation as the ADF anyway. Maybe some airplanes can't be degraded to that level or come with a lifetime warranty that says they will never have to make an emergency landing at some badly-lit primitive alternate. Lucky crews who fly this kit.
For as long as there is the potential for multiple failures and diversions to emergency aifields, at least one raw data, hand flown, engine out instrument approach to circle should be part of every annual test. Using what ever is the most degraded navigation equipment in the airplane. If the ADF receiver disappears, that would be the VOR, but without the benefit of the HSI. This requires the same level of interpretation as the ADF anyway. Maybe some airplanes can't be degraded to that level or come with a lifetime warranty that says they will never have to make an emergency landing at some badly-lit primitive alternate. Lucky crews who fly this kit.
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It is the circling stuff that I could do without. Call me a chicken, but I tend to like runway approaches.
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Dubrovnik was a classic example of a systemic failure and the Group commander was subsequently relieved of his command for gross negligence. The Air crash Investigators episode is rather a poor precis of the event unfortunately.
The whole lack of support to the 'front-enders' in this industry is a sad indictment of the times in both civil and military aviation. The higher-ups seem very happy to push crews to the limits in order to get the job done, even when commercial pressures are not a factor (self glorification perhaps?). I have studied this accident extensively for CRM trng purposes and the thing to take from it is that despite the pressures felt by the crew, there is one protecting shield that will prevent you becoming a statistic - strictly adhere to the rules of aviation. The crew made the following breaches in flight discipline in the conduct of the twin locator:
1. Commenced the appch way too fast (approx 80 kts above design criteria) in less than optimal config;
2. Continued the appch outside of tracking tolerances (possibly on INS);
3. Incorrect Navaid tuning during the appch. The wreckage reveiled the acft ADF was tuned to the first NDB/locator, thus the crew had no way of legally determining the MAP, which was o/h the second locator.
If the crew had properly responded to any of these criteria in the correct way (ie conducted a MAP immediately), the result could have been very different.
In fairness, there were many contributing factors to the error chain, such as badly interrupted min rest before the task, lack of a proper pre-flt briefing which included lengthy 'SPINS' (special instructions for mil ops), endorsed use of inaccurate/incorrect IAPs by the Group Command, and task focus pressure to get the high level Official to his meeting (or perhaps not get into trouble for failing to do so?). All these issues added to the difficulty of a flt conducted by a very fatigued crew.
The lesson is that aviation rules/SOPs were written in blood and you ignore them at your peril. It is hoped that all crews don't mean to breach the rules of any IAP, however, mistakes will certainly happen if you allow them to. The crew were warned by another mil Capt, who only just managed to get in previously, that the cloud base was at mins. The conduct of an unfamiliar appch with less than optimal Navaid set-up, in very poor wx, with proximity to significant terrain, would require thorough and careful consideration and execution. It would seem that this crew rushed themselves unnecessarily and opened the door to this fatal chain of events. A sobering lesson for all of us at the sharp end.
The whole lack of support to the 'front-enders' in this industry is a sad indictment of the times in both civil and military aviation. The higher-ups seem very happy to push crews to the limits in order to get the job done, even when commercial pressures are not a factor (self glorification perhaps?). I have studied this accident extensively for CRM trng purposes and the thing to take from it is that despite the pressures felt by the crew, there is one protecting shield that will prevent you becoming a statistic - strictly adhere to the rules of aviation. The crew made the following breaches in flight discipline in the conduct of the twin locator:
1. Commenced the appch way too fast (approx 80 kts above design criteria) in less than optimal config;
2. Continued the appch outside of tracking tolerances (possibly on INS);
3. Incorrect Navaid tuning during the appch. The wreckage reveiled the acft ADF was tuned to the first NDB/locator, thus the crew had no way of legally determining the MAP, which was o/h the second locator.
If the crew had properly responded to any of these criteria in the correct way (ie conducted a MAP immediately), the result could have been very different.
In fairness, there were many contributing factors to the error chain, such as badly interrupted min rest before the task, lack of a proper pre-flt briefing which included lengthy 'SPINS' (special instructions for mil ops), endorsed use of inaccurate/incorrect IAPs by the Group Command, and task focus pressure to get the high level Official to his meeting (or perhaps not get into trouble for failing to do so?). All these issues added to the difficulty of a flt conducted by a very fatigued crew.
The lesson is that aviation rules/SOPs were written in blood and you ignore them at your peril. It is hoped that all crews don't mean to breach the rules of any IAP, however, mistakes will certainly happen if you allow them to. The crew were warned by another mil Capt, who only just managed to get in previously, that the cloud base was at mins. The conduct of an unfamiliar appch with less than optimal Navaid set-up, in very poor wx, with proximity to significant terrain, would require thorough and careful consideration and execution. It would seem that this crew rushed themselves unnecessarily and opened the door to this fatal chain of events. A sobering lesson for all of us at the sharp end.
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I should correct an earlier statement where I said 'pre-GPS days'. The GPS system existed, but it is unlikely that the airplane had it, or even if it did, that it could be used. At the time, Uncle Sam often scrambled the network or shut it down due to the conflict in the area.
Regarding being 80 knots too fast at commencement of the approach, it would only take a couple of miles error in the INS for the crew to hit the IAF beacon earlier than expected. Anyone whoever flew with INS would be familiar with the problem and would not rely on it, but what was the level of training given to the crew, and just how experienced were they? Plenty of high-time airline Captains would not do much better in such unfamiliar surroundings with such inadequate equipment. In fact, most airlines would put their crews through at least a simulator 'visit' before expecting them to deal with the conditions those poor guys faced on that terrible night.
Regarding being 80 knots too fast at commencement of the approach, it would only take a couple of miles error in the INS for the crew to hit the IAF beacon earlier than expected. Anyone whoever flew with INS would be familiar with the problem and would not rely on it, but what was the level of training given to the crew, and just how experienced were they? Plenty of high-time airline Captains would not do much better in such unfamiliar surroundings with such inadequate equipment. In fact, most airlines would put their crews through at least a simulator 'visit' before expecting them to deal with the conditions those poor guys faced on that terrible night.
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Some airlines don't allow circling approaches in wide-body aircraft.
There are some exceptions to this, ie specific published circling procedures.
I am with the other guys straight in after a long flight anyday..........
There are some exceptions to this, ie specific published circling procedures.
I am with the other guys straight in after a long flight anyday..........
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The Wednesday 5th December show on Air Crash Investigators on Channel 7 (VIC) was actually about the Airbus A300-600 that crashed in New York because the Vertical Stab' sheared off.
Does anyone know when the B737 story will be aired???
Does anyone know when the B737 story will be aired???
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Some of you do enjoy your own opinions. While ML 16 was on the twin NDB approaches I operated in there using the 16 twin NDB app. Using LNAV & VNAV while monitoring raw data the RNP was fine but the aircraft was paralleling final. We were in VMC on this occasion & a good 2nm from ROC we were diverging from the 5* tolerance & well right of the extended centreline(trackline indicated on the centreline). Of course CWS was used to correct the track. On other occasions in IMC I had to manually correct the path in the same way. In short, sometimes with all the technology you must use raw data to correct and/or ensure tracking is accurate. If you don't you may as well trust the FMC to fly your vertical path as well without monitoring the DME etc. Checkies who test these competencies in my opinion are doing all aviation a service by reducing a CFIT incident. This air crash investigation concludes that the crew may not have properly monitored & flew by the ground based aids. Even though the B737NG reduces this risk right down, lateral tracking can sometimes be inaccurate with the FMC generated tracks, sometimes by up to 0.5 of a mile, which I have experienced.
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That would be a bugger an a RNP approach....... guess thats why we check and select a suitable RNP. Very rarely with GPS updating will the FMC be inaccurate to that extent.
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I watched that Dubrovnik B737 crash episode of Air Crash; it was their worst yet and I won't bother watching the next one.
The reporter was on the right track in some cases but filled the layman viewer's head with utter garbage when it is supposed to be presented in a format to be understood by anyone.
The heading error on final cannot, as I understand it, be attributed to INS drift and he interpreted NDB or LOC "station passage" as passing over a marker beacon.
He kept on about something to do with being able to hear the beacon and he was not referring specifically to the ident, now was he referring specifically to a marker beacon. I have no idea what he really meant and neither did he.
For a program professing to "investigate" accidents, they have no clue.
That presentation has little relevance to Australian airline aviation.
The reporter was on the right track in some cases but filled the layman viewer's head with utter garbage when it is supposed to be presented in a format to be understood by anyone.
The heading error on final cannot, as I understand it, be attributed to INS drift and he interpreted NDB or LOC "station passage" as passing over a marker beacon.
He kept on about something to do with being able to hear the beacon and he was not referring specifically to the ident, now was he referring specifically to a marker beacon. I have no idea what he really meant and neither did he.
For a program professing to "investigate" accidents, they have no clue.
That presentation has little relevance to Australian airline aviation.
CX current 777's all have ADF's. However, the next new lot of ER's will NOT have ADF's fitted.
If you failed both CDU's then .............mmmm I'll try it in the sim.
If you failed both CDU's then .............mmmm I'll try it in the sim.
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The CDUs are used (amongst other things) to tune the ADFs. If either or both CDUs fail, there is a third in the centre console which will take over the functions of either of the others.
The Navigation Displays present ADF information to the pilot. If both Navigation Display fails, the information from either ND can be brought up on the lower-centre display.
The Navigation Displays present ADF information to the pilot. If both Navigation Display fails, the information from either ND can be brought up on the lower-centre display.
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That was some B737-200 they were flying, it's the only one I've ever seen that had a B747 Classic flight deck.
The pax cabin must have been quite small, really!
Those crash investigators are a wizz at locating the relevant equipment, did you notice how he simply reached in thru a convenient panel and pulled out, what, the actual ADF indicator, what unbelievable luck!
Seriously, of recent times, I'm finding that ACI series a real comedy, it's good for entertainment value only, I nearly fell out of my chair laughing on several occasions, it's just way to amateur-ish for me to take it seriously!
Plus 'a million' other TV-isms I just enjoyed!
Cheers...FD...
The pax cabin must have been quite small, really!
Those crash investigators are a wizz at locating the relevant equipment, did you notice how he simply reached in thru a convenient panel and pulled out, what, the actual ADF indicator, what unbelievable luck!
Seriously, of recent times, I'm finding that ACI series a real comedy, it's good for entertainment value only, I nearly fell out of my chair laughing on several occasions, it's just way to amateur-ish for me to take it seriously!
Plus 'a million' other TV-isms I just enjoyed!
Cheers...FD...
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They seem to use the same cockpit for all episodes - kind-of has Airbus windows and a combination glass/dial set of displays. Clearly it'd cost a bit much to change flight decks every time to be totally accurate to type.
And it's not necessarily a show designed to be watched & picked apart by experts - hell, they're distilling reports which can run into hundreds of pages and be full of very technical stuff, into less than an hour - but I suggest on the whole, it gives interested punters a bit of an idea into what happened. To be honest, I suggest it gives punters a bit of comfort - out of all the flights which take off every day, this is how little goes wrong and how each incident/accident then contributes to overall flight safety - how the lessons are learnt and assimilated.
If you really want to know the nuts & bolts, you read the report.
And it's not necessarily a show designed to be watched & picked apart by experts - hell, they're distilling reports which can run into hundreds of pages and be full of very technical stuff, into less than an hour - but I suggest on the whole, it gives interested punters a bit of an idea into what happened. To be honest, I suggest it gives punters a bit of comfort - out of all the flights which take off every day, this is how little goes wrong and how each incident/accident then contributes to overall flight safety - how the lessons are learnt and assimilated.
If you really want to know the nuts & bolts, you read the report.
Last edited by Taildragger67; 12th Dec 2007 at 08:05.
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Taildragger67....
I don't know if you're actually in training to be a politician or some such other similar activity...
But you certainly know how to state the bleedin' obvious, in a long-winded fashion.
I think you can safely say that we are 'all' aware of the thrust of your comments, and take those circumstances as the norm in these situations.
Just to show I'm not trying to wind you up, I'll add here - "Thank you for your comments".
....and leave it at that!!
I don't know if you're actually in training to be a politician or some such other similar activity...
But you certainly know how to state the bleedin' obvious, in a long-winded fashion.
I think you can safely say that we are 'all' aware of the thrust of your comments, and take those circumstances as the norm in these situations.
Just to show I'm not trying to wind you up, I'll add here - "Thank you for your comments".
....and leave it at that!!
