longhauler wrote:

Max Q wrote:

Lhaul what was strange about AC’s 747 combis ?

It was only the -400s, as they were being considered when Air Canada was looking for a replacement for its -200 combis when this rule was being suggested. Boeing devised a version where the wall between the cargo and passengers was a fixed (air tight) part of the structure. It could withstand far greater smoke/fume and fire protection than the movable version. The hold also had it's own pack and outflow valve so they could "depressurize" the hold without depressurizing the rest of the cabin. There were other electrical variations too, allowing isolation of the hold.

When presented to Transport Canada, it was deemed acceptable and Air Canada placed the order for three.

However, during construction, Transport Canada announced they were not going to enforce this rule, allowing combi freighters in the arctic. While some of the features of the -400 combis could be reversed, the wall could not. It was a part of the structure. Some unlike most 747 combis where the wall could be placed at doors 4 or 3 or not at all, it was always at doors 4. It made the aircraft very difficult to sell when the time came.

Very interesting, if I understand correctly you could have a situation where the aft main deck of these aircraft could be depressurized while the passenger section in the front is unaffected with a normal cabin altitude


It sounds like a great idea with a main deck cargo fire but I can see how the immovable
bulkhead partition would greatly limit its flexibility and resale value


I assume converting this configuration to a regular combi would be uneconomic ?

BAe146 is closer than most, but again lack of a combi config does still limit it. At that point other than being a jet there's not really any advantage to it over the ATR. There are some 146s around, Summit was operating some for First Air out of YZF at one point, but I've heard First Air came to basically the same conclusion and those routes are on their own ATR42-500s now.


Also I forgot to mention in my first post that another factor is the northern airlines probably won't be buying anything new any time soon. Brand new airplanes often have astronomically high purchase prices and for the most part northern carriers just don't have the funds, utilization, or operating costs to justify the price.

Operating up north is a high cost environment. Fuel is expensive, in some places it has to be flown in on specialized fuel-hauling aircraft. Ground handling is expensive, often there is no real ground handler in the communities to airlines will have to train in house staff, lease airport space and buy GSE equipment even if they only operate three or four flights per week there. Hangars are expensive to heat. Things break more often when operating in the cold. Rough runways leave their marks even on gravel kitted airplanes. Aircraft utilization is limited by many communities only having enough business to justify a couple flights per week, and other airports that could fill more seats some of them can only be flown to in daylight hours. Simply put, even if the manufacturers did offer new gravel kitted jets after all of this is covered many of these northern airlines simply can't afford to go to Boeing or Airbus and say "hey we'll take 10 of those and 5 of these". It did happen back in the day with the 737-200Cs, but in those cases many of the operators buying them new were tied in with big operations down south from which they could source some cash, where as now many of the northern operators are their own airlines not directly linked to a major carrier.

Reminds me of Busy Bee's Boeing 737-2R4C in Norway. Had gravel kit and was also as the only 737 certified to be used for parachuting. Got to fly on this one back in the 80's.






I'm guessing a Boeing 727 could work. I beleave some of them was also fittet out with gravel kit ?

Hoping that an engineer happens to read this thread and this question…

What would be the largest intake diameter for which a practical vortex dissipator could be conceived? And then, in existing engines, which ones would fit the bill?

MDGLongBeach wrote:

Hello!

With the 737-200 program almost 30 years old, the need for a versatile airliner that has the ability to utilize small, unpaved, and secluded runways is only increasing. With airlines such as Canadian North, Air Inuit, Air North, Nolinor (which just refitted their 732s with modern avionics) and Alaska (which retired them 10 years ago now.. but probably could use something to rival everts and northern air cargo, which both rival Alaska in that aspect of flying.), and more airlines in South America, Africa etc.. Even though the need isn't that great since only a handful of airlines need this versatility, these villages rely on aircraft to receive goods, resources to survive. With that being said, the 737-200 is old, pretty much none low time airframes are left, and I suppose upgrading them will only give the plane an extra few years on the air. Here's my question: Are there any plans to replace the 737-200? I've seen people say the a319, which I wouldn't see fit since it's not possible to fit a gravel kit on their engines. Other people have mentioned the Avro, which is an ok short term solution, but not the best due to it having its production ended.. and the Dash 8, which is again an ok idea, but still doesn't have the capacity or speed or range of the 737-200. What are your thoughts?

-3star

If I were those companiesI would get the lowest cycle MD-80’s and the spares to go with it. Those planes will last a long time the DC-9 family has a ridiculous LOV limit they are built like tanks

Hey - if they are still flying C-47s up there, the 737-200 should be around a lot longer.

Dominion301 wrote:

I'm guessing a Boeing 727 could work. I beleave some of them was also fittet out with gravel kit ?

The 727 didn’t need/have a gravel kit for gravel runways.
[/quote]

Yet some apparently did:

https://en.wikipedia.org/wiki/Gravel_kit

Mortyman wrote:

Reminds me of Busy Bee's Boeing 737-2R4C in Norway. Had gravel kit and was also as the only 737 certified to be used for parachuting. Got to fly on this one back in the 80's.






I'm guessing a Boeing 727 could work. I beleave some of them was also fittet out with gravel kit ?

Trying to understand how you could parachute from a 737


How would you get a door open against the airstream to begin with ?

Max Q wrote:

I assume converting this configuration to a regular combi would be uneconomic ?

My understanding is that the three were eventually converted to pure freighters. It would seem like a huge undertaking removing the fixed wall, but I guess that is what happened.

But the separate AC and electrics never were installed, as the requirements were changed during construction.

Max Q wrote:

Trying to understand how you could parachute from a 737

How would you get a door open against the airstream to begin with ?

The rear left door was a little different. Like most 737 combis, it was fitted with internal airstairs. The door was hinged at the bottom and when lowered the airstairs followed. You can tell from the outside, as the door is wider and has no window. The door/stairs were raised and lowered hydraulically in normal operation. (and using gravity and a push from the inside in an emergency).

I am not familiar with this parachute certification, but I suppose with a door like that ... it is possible.

Check out this video. Starting from time 15:00, one can see the rear airstair operation on the 737 combi.

https://www.youtube.com/watch?v=PLxwNv6Y3C0

AN-148/158 have a frightful safety record. Shame it's a nice looking aircraft.

As to the topic I don't think there really is anything that will replace the -200 for some operators such as those up north.

longhauler wrote:

Max Q wrote:

I assume converting this configuration to a regular combi would be uneconomic ?

My understanding is that the three were eventually converted to pure freighters. It would seem like a huge undertaking removing the fixed wall, but I guess that is what happened.

But the separate AC and electrics never were installed, as the requirements were changed during construction.

Max Q wrote:

Trying to understand how you could parachute from a 737

How would you get a door open against the airstream to begin with ?

The rear left door was a little different. Like most 737 combis, it was fitted with internal airstairs. The door was hinged at the bottom and when lowered the airstairs followed. You can tell from the outside, as the door is wider and has no window. The door/stairs were raised and lowered hydraulically in normal operation. (and using gravity and a push from the inside in an emergency).

I am not familiar with this parachute certification, but I suppose with a door like that ... it is possible.

Check out this video. Starting from time 15:00, one can see the rear airstair operation on the 737 combi.

https://www.youtube.com/watch?v=PLxwNv6Y3C0

Thanks for that, very interesting to see the operation of that door and stairs, seems like a rugged design, probably heavier than
the integral stairs under 1L


As far as operating that door in flight though (without the stairs I’d think) for parachutists to exit I would think the air loads would twist it significantly, if not take it off


Quite unlike some 727’s that have been modified for jumping with the stairs removed

32andBelow wrote:

PEK777 wrote:

The Mighty 757? There are an increasing number on the second hand market.

No. Low turbofans fine work as they Injest travel. You need a smaller turbojet or a turboprop preferably one with a high wing.

Is this an issue specific to how turbofans ingest air or just a ground clearance issue? Because it does look like the 757 has similar engine clearance as the 737-200 because of its elevated landing gear.

CanadianNorth wrote:

BAe146 is closer than most, but again lack of a combi config does still limit it. At that point other than being a jet there's not really any advantage to it over the ATR.

Even if you discount the payload and cabin size, the 146 has a huge advantage in engine-out climb. That was one of the main sales pitches against the Fokker 100.

BAE also did design and certification work for a Combi variant, available as part of the 'Avroliner' relaunch in the early 90s but I don't remember any customer buying it.

That’s really interesting that the super jet and CS series was brought up, here’s a question, how small does the diameter of the engine have to be to be fit with a gravel kit? Maybe someone who can answer this will narrow down the options? Thanks for your responses everyone!

laxtrii wrote:

AN-148/158 have a frightful safety record. Shame it's a nice looking aircraft.

You mean, two frames crashed -- one via pilot error (on a training flight with a crew unfamiliar with the type); the other most probably pilot error (pitot tube heating switched off) -- are a frightful safety record for the type?

Max Q wrote:

Mortyman wrote:

Reminds me of Busy Bee's Boeing 737-2R4C in Norway. Had gravel kit and was also as the only 737 certified to be used for parachuting. Got to fly on this one back in the 80's.






I'm guessing a Boeing 727 could work. I beleave some of them was also fittet out with gravel kit ?

Trying to understand how you could parachute from a 737


How would you get a door open against the airstream to begin with ?

A bit of history:

Busy Bee was an airline which operated in Norway between 1966 and 1992. Entirely based around wet lease, in conducted a mix of regional services for larger airlines and the military, as well as corporate, ad hoc and inclusive tour charters.

From 1980 the airline operated a single Boeing 737-2R4C. The aircraft was bought through a partnership with the Norwegian Armed Forces, in which it was specially equipped to meet military needs. Specifically, it was a combi variant, which encompassed a side loading door and the possibility to quickly rearrange the interior between all-passenger, all-freight, combined passenger and freight, as well as VIP configuration. The aircraft was designed to be able to operate out from gravel runways and was also as the only 737 certified to be used for parachuting.

Aviano789 wrote:

leleko747 wrote:

I wonder if a BAe 146 with gravel kit would do the job.
Nice short runway performance, high wing...

The Embraer KC-390 would maybe be nice too, as stated by a friend above.
Embraer needs to make it civilian!

There are many Boeing 727s, with time on the airframes parked in Mojave Desert

I'm not sure what your obsession with the 727 is, but it certainly makes no sense in seeking a frame younger than the 737-200.

2Holer4Longhaul wrote:

Aviano789 wrote:

leleko747 wrote:

I wonder if a BAe 146 with gravel kit would do the job.
Nice short runway performance, high wing...

The Embraer KC-390 would maybe be nice too, as stated by a friend above.
Embraer needs to make it civilian!

There are many Boeing 727s, with time on the airframes parked in Mojave Desert

I'm not sure what your obsession with the 727 is, but it certainly makes no sense in seeking a frame younger than the 737-200.

and why not may I ask ?

Mortyman wrote:

2Holer4Longhaul wrote:

Aviano789 wrote:

There are many Boeing 727s, with time on the airframes parked in Mojave Desert

I'm not sure what your obsession with the 727 is, but it certainly makes no sense in seeking a frame younger than the 737-200.

and why not may I ask ?

Because the Boeing 727 is not a modern airframe by any stretch of the imagination. The 722 is older than the 732 by a few years, not to mention it being less efficient on account of being a trijet.

Pardon me if I'm asking a dumb question, but couldn't a T tail jet (say, CRJx), work as a sort of replacement for the 732? Engines shielded somewhat by wing, so with some deflectors on the LG, should be workable, no?

2Holer4Longhaul wrote:

Mortyman wrote:

2Holer4Longhaul wrote:

I'm not sure what your obsession with the 727 is, but it certainly makes no sense in seeking a frame younger than the 737-200.

and why not may I ask ?

Because the Boeing 727 is not a modern airframe by any stretch of the imagination. The 722 is older than the 732 by a few years, not to mention it being less efficient on account of being a trijet.

No, but there are still proabably more of them flying around as cargo and private aircraft and if they are short on modern choices for their particulare operation … Thje question here was what could be fitted with a gravel kit and that is still flying.

80+ posts in and no one has pointed out the obvious solution: Boeing should simply fire up the assembly line and produce about 20 additional 737-200's. While they are at they should upgrade to include modern IFE, wider seats and more leg room. Shouldn't really be too big of a job.

Mortyman wrote:

Max Q wrote:

Mortyman wrote:

Reminds me of Busy Bee's Boeing 737-2R4C in Norway. Had gravel kit and was also as the only 737 certified to be used for parachuting. Got to fly on this one back in the 80's.






I'm guessing a Boeing 727 could work. I beleave some of them was also fittet out with gravel kit ?

Trying to understand how you could parachute from a 737


How would you get a door open against the airstream to begin with ?

A bit of history:

Busy Bee was an airline which operated in Norway between 1966 and 1992. Entirely based around wet lease, in conducted a mix of regional services for larger airlines and the military, as well as corporate, ad hoc and inclusive tour charters.

From 1980 the airline operated a single Boeing 737-2R4C. The aircraft was bought through a partnership with the Norwegian Armed Forces, in which it was specially equipped to meet military needs. Specifically, it was a combi variant, which encompassed a side loading door and the possibility to quickly rearrange the interior between all-passenger, all-freight, combined passenger and freight, as well as VIP configuration. The aircraft was designed to be able to operate out from gravel runways and was also as the only 737 certified to be used for parachuting.

Thanks for that MT


I’m still trying to understand how the parachutists exited the aircraft

Nobody was interested in my suggestion. Hmmm....

I still reckon the A319 could be a cheap possibility. With the single outflow design of the V2500 engine it could be a fairly low acquisition cost airframe and as it sits higher than a 737, vortex destroyer kits could be fitted to the nose of the cowl.

Channex757 wrote:

Nobody was interested in my suggestion. Hmmm....

I still reckon the A319 could be a cheap possibility. With the single outflow design of the V2500 engine it could be a fairly low acquisition cost airframe and as it sits higher than a 737, vortex destroyer kits could be fitted to the nose of the cowl.

Mind you, my question about the largest intake to which a vortex dissipator could be fitted was in line with assessing your suggestion

But nobody reacted either, nor later when RR503 asked the same question.

mcg wrote:

80+ posts in and no one has pointed out the obvious solution: Boeing should simply fire up the assembly line and produce about 20 additional 737-200's. While they are at they should upgrade to include modern IFE, wider seats and more leg room. Shouldn't really be too big of a job.

It was noted upthread that there would be no market. The 732 combi's are used by northern airlines with low utilization and little money for capital investment based on my experience with them. Even the 'new' planes 4N, 7F and 5T have introduced in recent years have been 733/734/735s, far from new.

Mortyman wrote:

2Holer4Longhaul wrote:

Mortyman wrote:

and why not may I ask ?

Because the Boeing 727 is not a modern airframe by any stretch of the imagination. The 722 is older than the 732 by a few years, not to mention it being less efficient on account of being a trijet.

No, but there are still proabably more of them flying around as cargo and private aircraft and if they are short on modern choices for their particulare operation … Thje question here was what could be fitted with a gravel kit and that is still flying.

The ones still flying aren't exactly getting any younger, and I doubt the low-cycle ones in the desert were stored with resale/reactivation in mind (as in, they're probably not airworthy anymore).
A 737-200 replacement they are not. Not now and not in the future.

zeke wrote:

yzfElite wrote:

Does anyone know if the 734 and other newer variants can land on the ice/lake strips?

There are regular flights with A319s to the Australian Government ice runway in Antarctica.

https://www.google.com.hk/amp/amp.abc.n ... le/9516760

Iirc they have to use laser to cut the runway everytime before an A319 is to land there

Channex757 wrote:

For several reasons the A319 with IAE V2500 engines intrigues me for this role. The shape of the engine nacelle and height of the airframe could lend itself to a rough/ice field conversion.

These are starting to become available in volume so maybe one or two could find themselves in northern Canada once freighter versions are developed, or the A320 if the A319 is too short.

Is it?

flyingclrs727 wrote:

MDGLongBeach wrote:

Hello!

With the 737-200 program almost 30 years old, the need for a versatile airliner that has the ability to utilize small, unpaved, and secluded runways is only increasing.

Almost 30? It's over 50 years old!

Yup, even the new generation 737-300 is over 30 years old. Piedmont Airlines was the launch customer for the 737-300 and put it into service 33 years ago this month.

After a little more research I found an article on the Norwegian army’s use of Busy Bees 732 as a parachute aircraft


When used in this role they removed the right rear door completely and this is where
the paratroopers made their ‘exit’



Boeing did tests with an instrumented dummy that was ‘thrown out’ to prove the concept
and ensure clearance from the horizontal stabilizer



Interesting, operating with that door open must have been incredibly loud, more significantly
I’m surprised that wasn’t an issue structurally as cabin doors are usually an integral part of the airframe once closed

Phosphorus wrote:

laxtrii wrote:

AN-148/158 have a frightful safety record. Shame it's a nice looking aircraft.

You mean, two frames crashed -- one via pilot error (on a training flight with a crew unfamiliar with the type); the other most probably pilot error (pitot tube heating switched off) -- are a frightful safety record for the type?

With respect I think you have a limited understanding of this types operational history. There have been other incidents you are apparently not aware of. Such as the the March 2010 gear up landing at Samara. The fact that several operators of the types have been very critical of the types safety and reliability. GTK Rossiya cited issues with engines, APU, doors and manufacturing quality control and removed the type from it's fleet. The AN-158's are grounded for engine issues. This aircraft has been plagued by problems and indeed has a dubious safety record.

JustSomeDood wrote:

32andBelow wrote:

PEK777 wrote:

The Mighty 757? There are an increasing number on the second hand market.

No. Low turbofans fine work as they Injest travel. You need a smaller turbojet or a turboprop preferably one with a high wing.

Is this an issue specific to how turbofans ingest air or just a ground clearance issue? Because it does look like the 757 has similar engine clearance as the 737-200 because of its elevated landing gear.

The 757 has high bypass engines that would be much more likely to ingest gravel than the engines on a 732.

laxtrii wrote:

... GTK Rossiya ..... and removed the type from it's fleet.

This one was subject to much drama in Russian aviation circles. Basically, the Pulkovo Airlines-operated An-148 fleet was the backbone of its regional network, and LED was emerging as a hub -- a big no-no in Aeroflot dominated, Moscow-centric Russian skies of XXI century. Upon merger of Pulkovo Airlines into Rossiya, and integration with Aeroflot group, LED-centric network was dismembered, An-148 retired and parked, to the anguish and hand-wringing of the crews who actually worked on them.

Whether An-148 was indeed that bad? Personnel who worked on them, on discussion boards, did not think so. But it was deemed surplus, and retired. LED-based passengers have to go via Moscow most of the time, to get anywhere. Most of passengers in Russia do that anyway (even going from one point in Asian Russia to another point in Asian Russia often requires flying via Moscow, unless you are really lucky, and there is a connection via Novosibirsk), so now LED pax have to do that too.

N14AZ wrote:

What a pity this model wasn't more successful (.... or successful at all ...):


Source: https://www.klassiker-der-luftfahrt.de/ ... 4/695352#1

But it would have been too small as well.

I was thinking the same thing... but directly applied to the 737 Classic series.

DL757NYC wrote:

MDGLongBeach wrote:

Hello!

With the 737-200 program almost 30 years old, the need for a versatile airliner that has the ability to utilize small, unpaved, and secluded runways is only increasing. With airlines such as Canadian North, Air Inuit, Air North, Nolinor (which just refitted their 732s with modern avionics) and Alaska (which retired them 10 years ago now.. but probably could use something to rival everts and northern air cargo, which both rival Alaska in that aspect of flying.), and more airlines in South America, Africa etc.. Even though the need isn't that great since only a handful of airlines need this versatility, these villages rely on aircraft to receive goods, resources to survive. With that being said, the 737-200 is old, pretty much none low time airframes are left, and I suppose upgrading them will only give the plane an extra few years on the air. Here's my question: Are there any plans to replace the 737-200? I've seen people say the a319, which I wouldn't see fit since it's not possible to fit a gravel kit on their engines. Other people have mentioned the Avro, which is an ok short term solution, but not the best due to it having its production ended.. and the Dash 8, which is again an ok idea, but still doesn't have the capacity or speed or range of the 737-200. What are your thoughts?

-3star

If I were those companiesI would get the lowest cycle MD-80’s and the spares to go with it. Those planes will last a long time the DC-9 family has a ridiculous LOV limit they are built like tanks

Yeah... MD-80 is the lowest cost solution. With Allegiant, Delta, and American retiring the type, there will be examples with 35k+ hours and cycles left on the LOV.

I cannot imagine the gravel market is that big. The lost sales for new buyers, who fly intensely, won't justify developing. Eh... They still build BT-67s... So the market can be served.

Lightsaber

From what I’ve heard from some people who operate them, they’ve speculated that in internal discussions, the best option is the 717 but there aren’t any to be had and most are still too new for what they want.

I personally think the 732s have a ways to go yet up in the North.

PEK777 wrote:

The Mighty 757? There are an increasing number on the second hand market.

Have you ever seen a B757 spool up their engines on takeoff? You OFTEN will see mini tornadoes coming from the ground into the 40K+ engines. It would be a one trip plane.

CFM565A1 wrote:

From what I’ve heard from some people who operate them, they’ve speculated that in internal discussions, the best option is the 717 but there aren’t any to be had and most are still too new for what they want.

I personally think the 732s have a ways to go yet up in the North.

I wonder if there are any MD-87s to be had.. (Or perhaps a DC-9-51?)

USAirKid wrote:

CFM565A1 wrote:

From what I’ve heard from some people who operate them, they’ve speculated that in internal discussions, the best option is the 717 but there aren’t any to be had and most are still too new for what they want.

I personally think the 732s have a ways to go yet up in the North.

I wonder if there are any MD-87s to be had.. (Or perhaps a DC-9-51?)

I offered the same question to the folks I was chatting with. The main thing against MDs, the JT8D parts are costly to acquire and needing a lot of care. The MD90s aren’t any good either for the same thing (engines).

It would be a practical plane otherwise.

There is no rush for these -200 to be replaced as many of those airlines have their maintenance operations built to handle it.

I also note that the F28 was also certified for gravel operations. Both Canadian North and Transair operated them in the arctic.

Here is Air North's C-GANV on the *paved* ramp at CYDA/Dawson City today!

Nice pic of C-GANV, it was just put back into service last week after time off, and some maintenance.
Hopefully they get the whole Dawson Airport paved soon.

Max Q wrote:

Interesting, operating with that door open must have been incredibly loud, more significantly
I’m surprised that wasn’t an issue structurally as cabin doors are usually an integral part of the airframe once closed

The cabin doors take pressure loads, but you should not be taking inertial loads across the cabin doors. The door surround structure should be taking the inertial loads around the door opening. If the door had to react inertial loads there would be a good chance for the door frame to twist and the door to bind.

If the door is removed, there is no pressure load. Also, I imagine if the door is removed, the flight speeds are restricted which should lower the peak in flight inertial loads.