Danger of letting down based on NDB false overhead. B707 crash 1974
In my view, navigation is 'the management of errors'. No single navigation aid (even GPS) is free from errors of some sort. The cautious navigator or pilot needs to use all available aids - whatever they may be at the time. And the greater the risk of error, the greater should be the safety margin.
See also this report:- https://aviation-safety.net/database...?id=19660124-0
See also this report:- https://aviation-safety.net/database...?id=19660124-0
navigation is 'the management of errors'. No single navigation aid (even GPS) is free from errors of some sort. The cautious navigator or pilot needs to use all available aids
https://en.wikipedia.org/wiki/Korean...nes_Flight_902
megan,
Indeed, yes. The Mark 1 Eyeball (and the seat of his pants) is part of a navigator's equipment. Is the sun in the right place? Is Polaris (or Southern Cross) where it should be? Or, when sailing, why has the wind changed? Why are the waves coming from a different direction. Why is a cloud that shape, is it the top of mountain? Do those cumulus clouds indicate an island beneath?
Does the change of movement of my boat indicate land nearby - waves reflected off rocks or refracted down wind of an island?
There are similar signs when flying (perhaps the source of Centaurus' sixth sense). Every little indication should be used, however small.
Indeed, yes. The Mark 1 Eyeball (and the seat of his pants) is part of a navigator's equipment. Is the sun in the right place? Is Polaris (or Southern Cross) where it should be? Or, when sailing, why has the wind changed? Why are the waves coming from a different direction. Why is a cloud that shape, is it the top of mountain? Do those cumulus clouds indicate an island beneath?
Does the change of movement of my boat indicate land nearby - waves reflected off rocks or refracted down wind of an island?
There are similar signs when flying (perhaps the source of Centaurus' sixth sense). Every little indication should be used, however small.
Last edited by Bergerie1; 1st Jul 2017 at 10:34.
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There was INS fitted to 707s in 1974. Qantas fitted their first in 1971 and by 74 all were fitted. There was Doppler and navigators prior to that.
I'm not sure what Pan Am had by then but there is no doubt Bali was known as a challenging port.
Out of interest up to that time Qantas didn't operate to Bali but Pan Am did the SYD / DPS trip. From then Qantas did it 2x per week.
When QF got down to 2 x 707 we had about 2 years of the 3 or 4 day Bali trip and our boss couldn't figure out why we wouldn't bid for the 747?
I'm not sure what Pan Am had by then but there is no doubt Bali was known as a challenging port.
Out of interest up to that time Qantas didn't operate to Bali but Pan Am did the SYD / DPS trip. From then Qantas did it 2x per week.
When QF got down to 2 x 707 we had about 2 years of the 3 or 4 day Bali trip and our boss couldn't figure out why we wouldn't bid for the 747?
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and our boss couldn't figure out why we wouldn't bid for the 747?
A bit like the popularity of the AN PER and DRW trips with crew changes where crewing periodically forgot about folks and it took days to sort it out ..... of course, we always did the right thing and rang up ... after a while ... when it became absolutely obvious that they had forgotten all about us ...
A bit like the popularity of the AN PER and DRW trips with crew changes where crewing periodically forgot about folks and it took days to sort it out ..... of course, we always did the right thing and rang up ... after a while ... when it became absolutely obvious that they had forgotten all about us ...
Folks,
I see a number of comments containing the remark: "----- before BALI had radar".
So, now BALI has radar??
Would you actually rely on the radar for terrain clearance ---- and not just at BALI?? Do you believe ATC will not give you a clearance below LSA (by whatever name) or actively monitor you on a STAR that you might screw up??
I speak as somebody who knows the area ( and a much wider area) very well.
Tootle pip!!
PS: That was a bad year for "The World's Most Experienced Airline", they had several "experiences" that year +/-, including another B707 loss at Tahiti. Around about that era they put a B707 off the end of YSSY 34 (R now) in an abort.
PS2: PanAm B707-321 has two Bendix Doppler, with a common aerial, QF had two Marconi Doppler with a common aerial ---- they cold not be used as a position fix for a letdown, they were a DR position only. I know, I have flown them both.
PS3: To this day, there are far more "challenging" airfields than BALI. None of them are "challenging" as long as you stick to the SOPs., just some you have to work a bit harder.
I see a number of comments containing the remark: "----- before BALI had radar".
So, now BALI has radar??
Would you actually rely on the radar for terrain clearance ---- and not just at BALI?? Do you believe ATC will not give you a clearance below LSA (by whatever name) or actively monitor you on a STAR that you might screw up??
I speak as somebody who knows the area ( and a much wider area) very well.
Tootle pip!!
PS: That was a bad year for "The World's Most Experienced Airline", they had several "experiences" that year +/-, including another B707 loss at Tahiti. Around about that era they put a B707 off the end of YSSY 34 (R now) in an abort.
PS2: PanAm B707-321 has two Bendix Doppler, with a common aerial, QF had two Marconi Doppler with a common aerial ---- they cold not be used as a position fix for a letdown, they were a DR position only. I know, I have flown them both.
PS3: To this day, there are far more "challenging" airfields than BALI. None of them are "challenging" as long as you stick to the SOPs., just some you have to work a bit harder.
Wunwing,
I don't think all QF B707 had INS by 1974. As I recall it 1 A/C was fitted around 1971 or 72 to get everyone used to it and gain experience for the B747 classic. I remember the one INS CDU being fitted in the OH panel to the left, a rather useless place to use it for real nav.
I don't think all QF B707 had INS by 1974. As I recall it 1 A/C was fitted around 1971 or 72 to get everyone used to it and gain experience for the B747 classic. I remember the one INS CDU being fitted in the OH panel to the left, a rather useless place to use it for real nav.
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Would you actually rely on the radar for terrain clearance
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Interesting. I had a debate last year about the single QF INS. Its good to see that someone else remembers it. It was 1971 as I worked on the project as a LAME and went directly to FE training from that.
IF the 2 INS were not fitted by 1974 it was close. In 74 I took my wife on her first staff travel trip and 2 of the most senior Navs were on it as a retirement trip so I guess they would be the ones to turn out the lights.
IF the 2 INS were not fitted by 1974 it was close. In 74 I took my wife on her first staff travel trip and 2 of the most senior Navs were on it as a retirement trip so I guess they would be the ones to turn out the lights.
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Seems strange to have had no navigator and no INS.
Was a northern approach to Bali standard? Just looking at Google Earth, wouldn't it be far less difficult to burn a bit more fuel and time by going past the airport, descending over the ocean and then approaching from the south?
Maybe they had a plane to catch.
Was a northern approach to Bali standard? Just looking at Google Earth, wouldn't it be far less difficult to burn a bit more fuel and time by going past the airport, descending over the ocean and then approaching from the south?
Maybe they had a plane to catch.
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Here's a link to a 1971 article in popular mechanics: The Brain that Tells a 747 Where to Go! hailing the new miracle technology, the Carousel IV INS for the 747.
Last edited by CurtainTwitcher; 3rd Jul 2017 at 09:14.
ampan,
I can only speak for the UK legislation which specified that in certain areas of the world, where there were inadequate navigation aids, a qualified specialist navigator needed to be carried. Elsewhere, were there were adequate navigation aids, the pilots navigated themselves.
That has now been superseded by, first INS, and then GPS, and a combination of the two.
I can only speak for the UK legislation which specified that in certain areas of the world, where there were inadequate navigation aids, a qualified specialist navigator needed to be carried. Elsewhere, were there were adequate navigation aids, the pilots navigated themselves.
That has now been superseded by, first INS, and then GPS, and a combination of the two.
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The International Society of Air Safety Investigators
VOLUME 10, NO.2 WINTER, 1977
PROCEEDINGS
of the
EIGHTH INTERNATIONAL SEMINAR
3-6 OCTOBER 1977
…
THE ACCREDITED REPRESENTATIVE
William L. Lamb
CHIEF, FIELD INVESTIGATIONDIVISION
BUREAU OF ACCIDENT INVESTIGATION
NATIONAL TRANSPORTATION SAFETY BOARD
…
The investigation of the Pan American World Airways, Boeing 707-321 accident on the island of Bali, Indonesia, illustrates the role of the accredited representative, and how I tdiffers from the role I normally held-Investigator-in-Charge. I was the United States accredited representative, and I hope that this .saga of my adventures-and mis-adventures may throw some light on the differences between the roles of the IIC and the accredited representative.
…
Pan American Flight 812 was a scheduled international flight from Hong Kong to Sydney, with an en route stop at Denpasar, Bali. The flight departed Hong Kong at 1108Z, with an estimated en route time of 4 hours 23 minutes. The flight was routine except for difficulty in establishing radio contact with Bali approach control. Communications were established and the flight was cleared to descend from its cruising flight level of 350 to flight level 100. The flight contacted Bali Tower at flight level 110 and requested a lower altitude; seconds later, it reported over the station. This report was made at 1519; although a corrected ETA of 1527Z had been reported a few minutes before the aircraft began to descend. The 8-minute early arrival should have been a cue to the crew to verify their position. The flight was cleared to descend to 2,500 feet and landing instructions for runway 09 were issued. Shortly before 1527Z , the crew reported level at 2,500 feet and were instructed to report the runway in sight. At 1527, the crew asked,"Hey Tower, what's your visibility out there now." This was the last radio transmission from the aircraft. The wreckage was found on the north slopeof the mountains about 37 nm northwest of the airport at the 3,000-foot level.The flight path through the trees indicated a direction of flight of 155° to160° and a 15° to 25° noseup attitude.
…
The CVR revealed that, following the problem connected with establishing radio contact with the Bali Approach Control, the crew identified being overhead the airport by the swing of one of the two ADF's that were tuned to the NDB on the airport. The comment that "one's swinging, the other decided to wait," followed by the overhead report and the commencement of the approach descent, indicates the crew's actions.
The descent flight path derived by a computer generated plot was in error, because in making up the cards for the computer, someone, the keypunch operator or someone, entered an extra digit in one card and this cancelled several heading changes. This error was not noticed until much later; however, this mistake would only move the start of the descent a mile or so to the west and the descent would still have been made behind the mountains.
It is interesting to note that the VOR referred to by the crew is about 6 nm south, or beyond the airport from the direction PA812 was approaching. The VOR was operating but it was not being used by the crew of PA812.
...
VOLUME 10, NO.2 WINTER, 1977
PROCEEDINGS
of the
EIGHTH INTERNATIONAL SEMINAR
3-6 OCTOBER 1977
…
THE ACCREDITED REPRESENTATIVE
William L. Lamb
CHIEF, FIELD INVESTIGATIONDIVISION
BUREAU OF ACCIDENT INVESTIGATION
NATIONAL TRANSPORTATION SAFETY BOARD
…
The investigation of the Pan American World Airways, Boeing 707-321 accident on the island of Bali, Indonesia, illustrates the role of the accredited representative, and how I tdiffers from the role I normally held-Investigator-in-Charge. I was the United States accredited representative, and I hope that this .saga of my adventures-and mis-adventures may throw some light on the differences between the roles of the IIC and the accredited representative.
…
Pan American Flight 812 was a scheduled international flight from Hong Kong to Sydney, with an en route stop at Denpasar, Bali. The flight departed Hong Kong at 1108Z, with an estimated en route time of 4 hours 23 minutes. The flight was routine except for difficulty in establishing radio contact with Bali approach control. Communications were established and the flight was cleared to descend from its cruising flight level of 350 to flight level 100. The flight contacted Bali Tower at flight level 110 and requested a lower altitude; seconds later, it reported over the station. This report was made at 1519; although a corrected ETA of 1527Z had been reported a few minutes before the aircraft began to descend. The 8-minute early arrival should have been a cue to the crew to verify their position. The flight was cleared to descend to 2,500 feet and landing instructions for runway 09 were issued. Shortly before 1527Z , the crew reported level at 2,500 feet and were instructed to report the runway in sight. At 1527, the crew asked,"Hey Tower, what's your visibility out there now." This was the last radio transmission from the aircraft. The wreckage was found on the north slopeof the mountains about 37 nm northwest of the airport at the 3,000-foot level.The flight path through the trees indicated a direction of flight of 155° to160° and a 15° to 25° noseup attitude.
…
The CVR revealed that, following the problem connected with establishing radio contact with the Bali Approach Control, the crew identified being overhead the airport by the swing of one of the two ADF's that were tuned to the NDB on the airport. The comment that "one's swinging, the other decided to wait," followed by the overhead report and the commencement of the approach descent, indicates the crew's actions.
The descent flight path derived by a computer generated plot was in error, because in making up the cards for the computer, someone, the keypunch operator or someone, entered an extra digit in one card and this cancelled several heading changes. This error was not noticed until much later; however, this mistake would only move the start of the descent a mile or so to the west and the descent would still have been made behind the mountains.
It is interesting to note that the VOR referred to by the crew is about 6 nm south, or beyond the airport from the direction PA812 was approaching. The VOR was operating but it was not being used by the crew of PA812.
...
Last edited by ampan; 4th Jul 2017 at 00:27.
Twenty five years ago it was the same - on descent into DPS in an A330 from HKG and cleared to an altitude BELOW the MSA.
And it happened on several occasions!
On a slightly different note, 43 years ago I was ferrying an F27 from MEL to JNB and on the sector from SIN to Medan, approaching from the SE we were cleared to overfly and turn ‘right’ for a left downwind for RWY 05. Fortunately we had been warned that the controllers periodically had difficulty in translating their language into English and often got confused between their ‘left’ and ‘right’!
Needless to say, we ignored the instruction and made a safe landing.
Several months later a Garuda aircraft crashed into a mountain after following the ATC instruction to turn the wrong way!
And it happened on several occasions!
On a slightly different note, 43 years ago I was ferrying an F27 from MEL to JNB and on the sector from SIN to Medan, approaching from the SE we were cleared to overfly and turn ‘right’ for a left downwind for RWY 05. Fortunately we had been warned that the controllers periodically had difficulty in translating their language into English and often got confused between their ‘left’ and ‘right’!
Needless to say, we ignored the instruction and made a safe landing.
Several months later a Garuda aircraft crashed into a mountain after following the ATC instruction to turn the wrong way!
Last edited by Arsey Duck; 26th Feb 2024 at 23:13.
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Twenty five years ago it was the same -
I remember something about “night effect” from my CPL exam days and being told that at dusk or dawn you could kiss the ADF goodbye. My ATP examiner told me that he lost his crew chief in an NDB related accident in a DC3.
The NDB letdown into Bankstown under radar control from YSSY approach was probably the best approach but my main use for the ADF was to tune into a commercial radio station and use it to find the city I was going to.
The NDB letdown into Bankstown under radar control from YSSY approach was probably the best approach but my main use for the ADF was to tune into a commercial radio station and use it to find the city I was going to.
Our Hueys only had one ADF for navigation - our brilliant government paid to have the Tacan removed and a lead weight installed to keep the balance.
Doing IF training at Canberra, we would fly the Twin-NDB approach. Dial up the first one with the rotating dial (not numbered clicks, just roll till you hear the station) and fly the inbound leg. Overhead, mad scramble to dial the next one, identify, get back on the correct bearing, and hope for a high cloudbase. Luckily we were slow enough to have time for the nimble-fingered switch flicking between stations.
Doing IF training at Canberra, we would fly the Twin-NDB approach. Dial up the first one with the rotating dial (not numbered clicks, just roll till you hear the station) and fly the inbound leg. Overhead, mad scramble to dial the next one, identify, get back on the correct bearing, and hope for a high cloudbase. Luckily we were slow enough to have time for the nimble-fingered switch flicking between stations.