AW139 G-LBAL helicopter crash in Gillingham, Norfolk
Join Date: Mar 2005
Location: Holly Beach, Louisiana
Posts: 916
Likes: 0
Received 0 Likes
on
0 Posts
I have to suspect not.
We were routinely doing those takeoffs long before the SFTS system came into existence.
What was your Class Year?
Rotorspeed - a. very definitely.
There seem to be a lot of people who want to only use a helicopter like an airliner and deny the true flexibility it gives us.
The fixation on the 50 kt Vmini (common to many helos), whilst a recognition of the inaccuracies of the pitot-static system, ignores the benefit a low velocity indicator (whether based on doppler, intertial nav or whatever) brings to the party.
A vertical IF takeoff is a straightforward and safe manoeuvre, but only when practised regularly. It certainly wouldn't have cost 4 lives if they had used that technique in Norfolk - regardless of the legalities.
There seem to be a lot of people who want to only use a helicopter like an airliner and deny the true flexibility it gives us.
The fixation on the 50 kt Vmini (common to many helos), whilst a recognition of the inaccuracies of the pitot-static system, ignores the benefit a low velocity indicator (whether based on doppler, intertial nav or whatever) brings to the party.
A vertical IF takeoff is a straightforward and safe manoeuvre, but only when practised regularly. It certainly wouldn't have cost 4 lives if they had used that technique in Norfolk - regardless of the legalities.
Join Date: Aug 2006
Location: Below Escape Velocity
Posts: 416
Likes: 0
Received 0 Likes
on
0 Posts
Um... Lifting,
The fact that you can couple the AW139 in various modes below Vmini has nothing to do with the fact that you can't go IMC/IFR below 50KIAS/Vmini.
The fact that you can couple the AW139 in various modes below Vmini has nothing to do with the fact that you can't go IMC/IFR below 50KIAS/Vmini.
In post #536, chopjock discusses using the FD modes to do a towering takeoff, which can't be done without failing to conform. No disagreement here.
Perhaps it would have been better to not "conform" and do the towering take off using the coupled functions of the autopilot at his discretion instead.
Normally, in the AW139, a towering takeoff is considered complete (depending upon one's company operating manuals) when established at a Vtoss of 50KIAS in an accelerating climb toward Vy, normally above 200'.
Most company operations manuals require a Cat A Runway takeoff for IMC, the profile for which is designed to allow the aircraft to achieve 50KIAS at a low altitude while still remaining visual. It is common for FD modes to be engaged around Vy, which is 80KIAS. This altitude / airspeed profile is generally not suitable for off airport locations where obstacle clearance can't be guaranteed. I don't have my Supplement 12 right here handy, so I can't confirm the profile in the RFM, but I recall it being identical.
Join Date: Mar 2005
Location: Holly Beach, Louisiana
Posts: 916
Likes: 0
Received 0 Likes
on
0 Posts
Um,
Does the 139 AFCS have SAS, ATT modes similar in concept to the Sperry system as used on the 212/412/76 families of helicopters? Those Modes were "Un-coupled" but greatly added Stability to the Aircraft especially when the Attitude Mode was engaged. Depressing the Cyclic Trim Release acted to over ride the Attitude Hold and allowed a new reference datum to be created.
SAS and ATT worked at all airspeeds. I would be surprised if the 139 system works much different.
Does the 139 AFCS have SAS, ATT modes similar in concept to the Sperry system as used on the 212/412/76 families of helicopters? Those Modes were "Un-coupled" but greatly added Stability to the Aircraft especially when the Attitude Mode was engaged. Depressing the Cyclic Trim Release acted to over ride the Attitude Hold and allowed a new reference datum to be created.
SAS and ATT worked at all airspeeds. I would be surprised if the 139 system works much different.
Join Date: Jun 2000
Location: UK
Posts: 231
Likes: 0
Received 0 Likes
on
0 Posts
Agree with Crab again I do
True, if you are stupid enough to bend the common sense rules of taking off at night in fog then be clever enough to use the aircraft to its full potential.
4 axis AW139, Pre-set a sensible ALTA figure, TAWS on (for the big picture once airborne and climbing) pop up gently to 30' select hover, then collective beep up to a height that you know will clear your nearest obstacles and begin to cyclic beep your speed. You can continue to beep height as you go. (If worried about the Radalts tracking over uneven terrain use ALT from 30' it will work even below the MUH) Once at 60KIAS use ALTA & HDG/RNAV and Bobs your uncle.....all fully coupled Take off IMC.
Practise the technique in a nice day VMC environment first on a regular basis is you think you will be 'pushing' your ops that way.
4 axis AW139, Pre-set a sensible ALTA figure, TAWS on (for the big picture once airborne and climbing) pop up gently to 30' select hover, then collective beep up to a height that you know will clear your nearest obstacles and begin to cyclic beep your speed. You can continue to beep height as you go. (If worried about the Radalts tracking over uneven terrain use ALT from 30' it will work even below the MUH) Once at 60KIAS use ALTA & HDG/RNAV and Bobs your uncle.....all fully coupled Take off IMC.
Practise the technique in a nice day VMC environment first on a regular basis is you think you will be 'pushing' your ops that way.
Join Date: Aug 2006
Location: Below Escape Velocity
Posts: 416
Likes: 0
Received 0 Likes
on
0 Posts
Bob-
Yes. Though I'm not going to wade into this swamp, though, with what coulda, shoulda, woulda been done. No, sirree... but suffice it to say that the AW139 is a pretty capable machine, even in the more basic configurations one occasionally finds.
Yes. Though I'm not going to wade into this swamp, though, with what coulda, shoulda, woulda been done. No, sirree... but suffice it to say that the AW139 is a pretty capable machine, even in the more basic configurations one occasionally finds.
Auto-flight
The automatic flight control system (AFCS) is controlled by the two modular avionics units (MAU) of the PRIMUS EPIC ® system. The MAUs process information for the AFCS and are connected to the following components:
- The autopilot controller
- The guidance controller
- Linear-actuators
- Rotary trim actuators
- Air data modules
- Attitude and reference systems
The AFCS has the following two basic modes of operation:
- Attitude retention mode (ATT)
- Stability augmentation system mode (SAS)
The ATT retention mode permits long term stabilisation for hands-off flying and it can be coupled to the flight director commands. SAS mode gives short-term damping for hands-on flying.
The yaw control function is engaged automatically when the auto-pilot is selected.
The yaw control remains active in both ATT and SAS mode. Dual yaw control is provided when both auto-pilots are engaged.
The collective axis of the AFCS drives the helicopter collective controls. The collective controls are linked to a parallel actuator and a force feel assembly to give the pilot motive power and artificial feel. The auto-trim system controls the linear actuators and keeps them in their center-of-travel position. Pitch and roll auto-trim is functional when one or both auto-pilots are engaged in any mode, except SAS mode.
The automatic flight control system (AFCS) is controlled by the two modular avionics units (MAU) of the PRIMUS EPIC ® system. The MAUs process information for the AFCS and are connected to the following components:
- The autopilot controller
- The guidance controller
- Linear-actuators
- Rotary trim actuators
- Air data modules
- Attitude and reference systems
The AFCS has the following two basic modes of operation:
- Attitude retention mode (ATT)
- Stability augmentation system mode (SAS)
The ATT retention mode permits long term stabilisation for hands-off flying and it can be coupled to the flight director commands. SAS mode gives short-term damping for hands-on flying.
The yaw control function is engaged automatically when the auto-pilot is selected.
The yaw control remains active in both ATT and SAS mode. Dual yaw control is provided when both auto-pilots are engaged.
The collective axis of the AFCS drives the helicopter collective controls. The collective controls are linked to a parallel actuator and a force feel assembly to give the pilot motive power and artificial feel. The auto-trim system controls the linear actuators and keeps them in their center-of-travel position. Pitch and roll auto-trim is functional when one or both auto-pilots are engaged in any mode, except SAS mode.
Join Date: May 2011
Location: In Communicado
Posts: 106
Likes: 0
Received 0 Likes
on
0 Posts
BB,
Let's just say I'm of the "blue box" generation so I am fully aware of the training maneuver used while wearing the horse blinders in the real aircraft. But those take-offs were done from a runway, not from a field site surrounded by obstructions.
My question remains - have you done a 0/0 take-off in he actual aircraft? In actual 0/0 (or even near that) conditions?
I would wonder how the Ops Officer would have signed your flight release without an available departure alternate.
The AW139 does indeed have the ATT/SAS modes you describe and your comment on pilot technique is correct. But, as others have mentioned, most FD modes do not engage before 60kts (lower values for some in the latest Phase 7 software). In addition, SAR modes can do wonderful things, but they are not intended for IMC at those low speeds and do not provide obstruction clearance.
Let's just say I'm of the "blue box" generation so I am fully aware of the training maneuver used while wearing the horse blinders in the real aircraft. But those take-offs were done from a runway, not from a field site surrounded by obstructions.
My question remains - have you done a 0/0 take-off in he actual aircraft? In actual 0/0 (or even near that) conditions?
I would wonder how the Ops Officer would have signed your flight release without an available departure alternate.
The AW139 does indeed have the ATT/SAS modes you describe and your comment on pilot technique is correct. But, as others have mentioned, most FD modes do not engage before 60kts (lower values for some in the latest Phase 7 software). In addition, SAR modes can do wonderful things, but they are not intended for IMC at those low speeds and do not provide obstruction clearance.
Join Date: Mar 2005
Location: Holly Beach, Louisiana
Posts: 916
Likes: 0
Received 0 Likes
on
0 Posts
My question remains - have you done a 0/0 take-off in he actual aircraft? In actual 0/0 (or even near that) conditions?
I would wonder how the Ops Officer would have signed your flight release without an available departure alternate.
You should also know we got a bit of weather briefing in the morning before take-off and none the rest of the day with a return quite late in the dark on more than a few occasions as well. You might tell folks about the great abundance of weather reporting in the AO we operated in during those years and all of the Navaids we did not have. Perhaps you can educate them on Tactical Figure Eight Approaches using FM Homing while you are at it.
Or did you miss out on all those fun and games somehow?
If you never got to do that kind of flying then perhaps you might tell us a bit about your Instrument Flying experience in the Army.
If you flew the Blue Canoe then you know how useless that system was.
Likewise if you did fly the SFTS, then you can explain to everyone why doing an Instrument Take Off in that device was even harder than in the actual Aircraft due to the absolute absence of any external cues.
So H, do tell us where you are coming from when you want to talk Army Instrument flying Techniques performed in the Real World. Did you have any? Did you obtain an Army Instrument Rating beyond the Tactical Instrument Rating?
What Instrument Ratings have you had in the Civilian World?
Now, any more questions?
Last edited by Boudreaux Bob; 14th Apr 2014 at 04:21.
Join Date: May 2011
Location: In Communicado
Posts: 106
Likes: 0
Received 0 Likes
on
0 Posts
Well, Bob...
I am quite familiar with your long list and am very familiar with all you say there.
I don't believe, however, that a comparison with those days very nearly 50 years ago serves any purpose in today's professional civilian aviation world. When entrusted with paying passengers, I would hope we would apply a higher standard than when hauling grunts in and out of combat in those days long ago. We have matured (as individuals and as an industry) have we not?
So, no, no more questions. I think I can see where you stand.
I am quite familiar with your long list and am very familiar with all you say there.
I don't believe, however, that a comparison with those days very nearly 50 years ago serves any purpose in today's professional civilian aviation world. When entrusted with paying passengers, I would hope we would apply a higher standard than when hauling grunts in and out of combat in those days long ago. We have matured (as individuals and as an industry) have we not?
So, no, no more questions. I think I can see where you stand.
Join Date: Mar 2005
Location: Holly Beach, Louisiana
Posts: 916
Likes: 0
Received 0 Likes
on
0 Posts
I guess you don't have any answers to the questions. Sorry, if I scared you off by asking you about your experience. It did seem fair as you asked about mine.
Join Date: May 2011
Location: In Communicado
Posts: 106
Likes: 0
Received 0 Likes
on
0 Posts
BB,
I did not inquire about your qualifications. I only asked if you had done real 0/0 departures. Not training, not simulated.
No fear involved here, but throwing credentials about serves little purpose.
You are entitled to your opinion and I to mine. No offense intended and no CV required although I doubt we are far apart.
I did not inquire about your qualifications. I only asked if you had done real 0/0 departures. Not training, not simulated.
No fear involved here, but throwing credentials about serves little purpose.
You are entitled to your opinion and I to mine. No offense intended and no CV required although I doubt we are far apart.
Join Date: Nov 2005
Location: the top of the flag pole
Posts: 78
Likes: 0
Received 0 Likes
on
0 Posts
Jon902,
Are your 150m RVR limited to when Low Vis Procedures are in force?
Without LVPs we need 400m RVR for a Performance Class 1, IFR departure.
Many aerodromes don't operate LVPs.
Rotorspeed,
Answer; None of the above). NRDK describes a fully coupled technique well, and his point about uneven terrain is important, but you still have to get up to 30ft, to engage HOV mode, and anyway you did say 'hand flown'.
Type rating training involves VMC take off profiles until through TDP and Vmini.
A towering take off by sole reference to instruments, below TDP, is not one many people train for. I'm sure many IFR qualified pilots may be able to take off on instruments in zero/zero, but only with suitable training and practice. When things don't go quite to plan one would not be well placed. Not much scope to sort things out one might say. So not one for my everyday bag of tricks, thank you.
Um...Lifting,
I've put the stick down and washed my hands - thanks.
With regard to a 139 towering take off you said
.
We use 40 KIAS for Vtoss for towering (Helipad/Heliport and Offshore) - 50 KIAS Clear area.
But, normally, it starts with visual lateral hover cues and remains that way until through TDP and Vmini. So, loose the cues too early and you are flying through the next hole in the swiss cheese.
I say 'next hole' because you've already made it through a few, prior to being in the hover with no external take off cues.
Are your 150m RVR limited to when Low Vis Procedures are in force?
Without LVPs we need 400m RVR for a Performance Class 1, IFR departure.
Many aerodromes don't operate LVPs.
Rotorspeed,
Answer; None of the above). NRDK describes a fully coupled technique well, and his point about uneven terrain is important, but you still have to get up to 30ft, to engage HOV mode, and anyway you did say 'hand flown'.
Type rating training involves VMC take off profiles until through TDP and Vmini.
A towering take off by sole reference to instruments, below TDP, is not one many people train for. I'm sure many IFR qualified pilots may be able to take off on instruments in zero/zero, but only with suitable training and practice. When things don't go quite to plan one would not be well placed. Not much scope to sort things out one might say. So not one for my everyday bag of tricks, thank you.
Um...Lifting,
I've put the stick down and washed my hands - thanks.
With regard to a 139 towering take off you said
Normally, in the AW139, a towering takeoff is considered complete (depending upon one's company operating manuals) when established at a Vtoss of 50KIAS in an accelerating climb toward Vy, normally above 200'.
We use 40 KIAS for Vtoss for towering (Helipad/Heliport and Offshore) - 50 KIAS Clear area.
But, normally, it starts with visual lateral hover cues and remains that way until through TDP and Vmini. So, loose the cues too early and you are flying through the next hole in the swiss cheese.
I say 'next hole' because you've already made it through a few, prior to being in the hover with no external take off cues.
Join Date: Aug 2006
Location: Below Escape Velocity
Posts: 416
Likes: 0
Received 0 Likes
on
0 Posts
We use 40 KIAS for Vtoss for towering (Helipad/Heliport and Offshore) - 50 KIAS Clear area.
But, normally, it starts with visual lateral hover cues and remains that way until through TDP and Vmini. So, loose the cues too early and you are flying through the next hole in the swiss cheese.
I say 'next hole' because you've already made it through a few, prior to being in the hover with no external take off cues.
But, normally, it starts with visual lateral hover cues and remains that way until through TDP and Vmini. So, loose the cues too early and you are flying through the next hole in the swiss cheese.
I say 'next hole' because you've already made it through a few, prior to being in the hover with no external take off cues.
I was kind of making an overarching statement based upon a few others I've seen and heard about as well.
Again, no disagreement with anything you put above, but all things considered, I think I'll have a cup of coffee.
Boudreaux Bob: I had a special instrument card. I was one of the experienced pilots in my squadron who could have been tasked with a mission where a 0/0 takeoff might have been on the menu.
Never did one "for real." Practicied a bunch of them in the sim, and with the hood/blinders on during instrument checks. It helped that the aircraft I was flying at the time also had a doppler system with full coupled hover capability. It was still a spooky/demanding maneuver to get right, and you needed to have your instrument scan running smoothely.
The Special Instrument Rating language in the OPNAVINST 3710 series included in the authorization for 0/0 take offs, both rotary wing and fixed wing, the matter of operational necessity -- a requirement before one could be authorized/attempted.
Operational necessity had a strict definition. The importance of the mission rendered the risk of losing the crew and aircraft acceptable. Usually, that level of risk decision was at the wing or a flag officer level. Squadron Ops officer? Not.
Let us apply the above line of thinking to the commercial pilot/captain in this accident.
Let us suppose that he had practiced and was reasonably proficient at combining an obstacle clearance take off with an instrument take off. (I will set aside for a moment the hard to get around rule for that model of aircraft of VminI from the RFM, 50 KIAS, which would be like a limitation in the NATOPS manual or the -10 for you or I in those military years).
He's in an unprepared field, his vis is crap, it's now night (with IIRC an original "before sunset" launch time). He is in a position to do one of those "0/0" like take offs, or choose not to.
Does his mission meet operational necessity requirements? Is what he was doing worth risking the loss of crew, pax, and aircraft?
I think you would be on side with the majority of us by answering "no" in this case. His employer probably never considered that line of thinking, unlike how flag officers and wing commanders in the service considered such things before authorizing or rejecting permission for such ops.
Never did one "for real." Practicied a bunch of them in the sim, and with the hood/blinders on during instrument checks. It helped that the aircraft I was flying at the time also had a doppler system with full coupled hover capability. It was still a spooky/demanding maneuver to get right, and you needed to have your instrument scan running smoothely.
The Special Instrument Rating language in the OPNAVINST 3710 series included in the authorization for 0/0 take offs, both rotary wing and fixed wing, the matter of operational necessity -- a requirement before one could be authorized/attempted.
Operational necessity had a strict definition. The importance of the mission rendered the risk of losing the crew and aircraft acceptable. Usually, that level of risk decision was at the wing or a flag officer level. Squadron Ops officer? Not.
Let us apply the above line of thinking to the commercial pilot/captain in this accident.
Let us suppose that he had practiced and was reasonably proficient at combining an obstacle clearance take off with an instrument take off. (I will set aside for a moment the hard to get around rule for that model of aircraft of VminI from the RFM, 50 KIAS, which would be like a limitation in the NATOPS manual or the -10 for you or I in those military years).
He's in an unprepared field, his vis is crap, it's now night (with IIRC an original "before sunset" launch time). He is in a position to do one of those "0/0" like take offs, or choose not to.
Does his mission meet operational necessity requirements? Is what he was doing worth risking the loss of crew, pax, and aircraft?
I think you would be on side with the majority of us by answering "no" in this case. His employer probably never considered that line of thinking, unlike how flag officers and wing commanders in the service considered such things before authorizing or rejecting permission for such ops.
Join Date: Mar 2005
Location: Holly Beach, Louisiana
Posts: 916
Likes: 0
Received 0 Likes
on
0 Posts
Lone,
What ever makes you think I am suggesting departing in the scenario you painted that closely approximates the situation the Crew was confronted with that night in Norfolk?
Military flying in combat is one thing and Corporate flying is quite another.
Once I lost the option to Legally depart from that field site I would have notified my Passengers and ensured they had overnight accommodation and I would have secured the aircraft and headed to the Pub for a Pint.
What the discussion has been about is how one "would" do such a take off in an aircraft equipped such as the one in question if One "were" to do so.
No one has suggested anywhere that I have seen that it would be the thing "to do". Quite the contrary, everyone seems to suggest it was "not" the thing to do.
As to doing the 0/0 take off thing, perch your aircraft on the deck edge of an elevated heli-deck offshore on a nasty night facing away from the Rig/Platform and any visible light and tell me about a visual transition to instruments after being at Vy and above MSALT! The instant you dip the nose on takeoff you are off into the Black Abyss. Every North Sea Offshore Pilot knows that as they do it very often.
The Army had different levels of clearance authorities and the highest level allowed the Pilot to be his own clearance authority and make 0/0 Takeoffs in helicopters and airplanes.
Those rules got scant notice during Vietnam combat operations for any number of reasons.
We pretty much just got after it and did whatever had to be done. We were judicious about how we went about it but the "Rule Book" was just a dusty Tome stuck into a Book Rack in Ops.
Most of my white hair came from such flying. My concern was not the take off but the landing part definitely was.
What ever makes you think I am suggesting departing in the scenario you painted that closely approximates the situation the Crew was confronted with that night in Norfolk?
Military flying in combat is one thing and Corporate flying is quite another.
Once I lost the option to Legally depart from that field site I would have notified my Passengers and ensured they had overnight accommodation and I would have secured the aircraft and headed to the Pub for a Pint.
What the discussion has been about is how one "would" do such a take off in an aircraft equipped such as the one in question if One "were" to do so.
No one has suggested anywhere that I have seen that it would be the thing "to do". Quite the contrary, everyone seems to suggest it was "not" the thing to do.
As to doing the 0/0 take off thing, perch your aircraft on the deck edge of an elevated heli-deck offshore on a nasty night facing away from the Rig/Platform and any visible light and tell me about a visual transition to instruments after being at Vy and above MSALT! The instant you dip the nose on takeoff you are off into the Black Abyss. Every North Sea Offshore Pilot knows that as they do it very often.
The Army had different levels of clearance authorities and the highest level allowed the Pilot to be his own clearance authority and make 0/0 Takeoffs in helicopters and airplanes.
Those rules got scant notice during Vietnam combat operations for any number of reasons.
We pretty much just got after it and did whatever had to be done. We were judicious about how we went about it but the "Rule Book" was just a dusty Tome stuck into a Book Rack in Ops.
Most of my white hair came from such flying. My concern was not the take off but the landing part definitely was.
Bob quotes:
"As to doing the 0/0 take off thing, perch your aircraft on the deck edge of an elevated heli-deck offshore on a nasty night facing away from the Rig/Platform and any visible light and tell me about a visual transition to instruments after being at Vy and above MSALT! The instant you dip the nose on takeoff you are off into the Black Abyss. Every North Sea Offshore Pilot knows that as they do it very often."
You beat me to it, Bob. All this talk of attaining 50 kts before going IMC ... the most uncomfortable regular take-offs I ever encountered were in the 61N on the North Sea when after lifting in the turbulence on a Forties platform in the brilliant glare of the gas flare one then headed into complete blackness whilst gaining climbing speed, and then maybe had to repeat the exercise several times if one was on a "shuttle" when one had to repeatedly go from visual to instruments and back again.
"As to doing the 0/0 take off thing, perch your aircraft on the deck edge of an elevated heli-deck offshore on a nasty night facing away from the Rig/Platform and any visible light and tell me about a visual transition to instruments after being at Vy and above MSALT! The instant you dip the nose on takeoff you are off into the Black Abyss. Every North Sea Offshore Pilot knows that as they do it very often."
You beat me to it, Bob. All this talk of attaining 50 kts before going IMC ... the most uncomfortable regular take-offs I ever encountered were in the 61N on the North Sea when after lifting in the turbulence on a Forties platform in the brilliant glare of the gas flare one then headed into complete blackness whilst gaining climbing speed, and then maybe had to repeat the exercise several times if one was on a "shuttle" when one had to repeatedly go from visual to instruments and back again.
Join Date: Feb 2009
Location: Do I come here often?
Posts: 898
Likes: 0
Received 0 Likes
on
0 Posts
76Fan;
We all did those, despite the fact that all ops manuals required us to be visual with the reject area (usually the oggin in this case) I can't remember VMini on the S61, even if it had one, but I suspect it probably matched VToss.
It is difficult to compare the off shore and on shore procedures in this case, but off shore you normally had 100' head start and were pointed away from the worst of the nearby obstructions when pulling power. I have never flown the 139, but am well aware that IFR flight on both types I currently fly is hard work below VMini (60kt on one, 55kt on the other) Both aircraft "waffle about" and are extremely pitch sensitive and require careful flying. With low experience, close to the ground and proper IMC both could be serious handfuls.
SND
We all did those, despite the fact that all ops manuals required us to be visual with the reject area (usually the oggin in this case) I can't remember VMini on the S61, even if it had one, but I suspect it probably matched VToss.
It is difficult to compare the off shore and on shore procedures in this case, but off shore you normally had 100' head start and were pointed away from the worst of the nearby obstructions when pulling power. I have never flown the 139, but am well aware that IFR flight on both types I currently fly is hard work below VMini (60kt on one, 55kt on the other) Both aircraft "waffle about" and are extremely pitch sensitive and require careful flying. With low experience, close to the ground and proper IMC both could be serious handfuls.
SND
Bob, you were discussing where rules come from. I was discussing some rules related to 0/0 take offs, and instrument take offs.
The rules on 0/0 included a risk evaluation on how acceptable it is to lose the crew and aircraft versus how badly a mission needs to be done. When in a shooting war, that risk calculus is different from other times, as I am sure your experiences would confirm. Hell, you're already being shot at!
The ITO from the oil rig and taking off on a pitch black night, no moon, IMC from a pitching deck are similar if not identical flight regimes. An ITO is what you want to be doing. When you practice it, and when you stay proficient at it, that flight event is demanding but doable. At sea, on a ship, if you are zero zero, and homeplate is the only place besides the ocean to land, a 0/0 take off isn't what you'll generally opt for ... for obvious reasons.
You had made an earlier point about judgment and rules. I remember an infamous line in our "rules" in the OPNAVINST 3710 series: nothing in this manual precludes the exercise of good judgment. (Words to that effect).
The theme weaving in and out of your posts for the past few pages is the relationship between the rules and judgment. In this accident, particularly once the pitch attitude achieved during the takeoff was revealed by the initial comments from AAIB, it is hard not to believe that a core issue is the combination of judgment and airmanship.
As I considered the RFM requirement for no less than 50 knots before IMC (VminI) for this model, I began to see what the pilot might have been trying to do, in terms of trying to fit the rules to his situation.
Nothing further, back to lurk mode.
The rules on 0/0 included a risk evaluation on how acceptable it is to lose the crew and aircraft versus how badly a mission needs to be done. When in a shooting war, that risk calculus is different from other times, as I am sure your experiences would confirm. Hell, you're already being shot at!
The ITO from the oil rig and taking off on a pitch black night, no moon, IMC from a pitching deck are similar if not identical flight regimes. An ITO is what you want to be doing. When you practice it, and when you stay proficient at it, that flight event is demanding but doable. At sea, on a ship, if you are zero zero, and homeplate is the only place besides the ocean to land, a 0/0 take off isn't what you'll generally opt for ... for obvious reasons.
You had made an earlier point about judgment and rules. I remember an infamous line in our "rules" in the OPNAVINST 3710 series: nothing in this manual precludes the exercise of good judgment. (Words to that effect).
The theme weaving in and out of your posts for the past few pages is the relationship between the rules and judgment. In this accident, particularly once the pitch attitude achieved during the takeoff was revealed by the initial comments from AAIB, it is hard not to believe that a core issue is the combination of judgment and airmanship.
As I considered the RFM requirement for no less than 50 knots before IMC (VminI) for this model, I began to see what the pilot might have been trying to do, in terms of trying to fit the rules to his situation.
Nothing further, back to lurk mode.
Join Date: Feb 2001
Location: Europe
Posts: 535
Likes: 0
Received 0 Likes
on
0 Posts
Interesting responses to my question about the difficulty of 0/0 towering take offs. Crab - I agree with you 100%. In my experience, they are quite straightforward when hand flown, obviously with SAS engaged. I'm a bit surprised that not more agree. I learnt and practised them on original (Bristows) IR training, and ongoing practice is actually very easy to achieve - from a sensible area in VMC daylight just climb vertically, only with reference to the instruments. The key to me is getting fully stabilised - with visual reference - in the hover, then implanting that hover AI picture in your mind and maintaining it and heading, as close to max take off power is pulled. I've never used doppler etc but I've never found the acft drifted much, though as a check a max zoomed in route line to a waypoint in take off direction can be used.
I certainly would only want to do this with a good power margin though - the briefer the climb the easier it is and less any drift can occur. I think I recalled the 139 was initially going into Coventry 20 mins away (for fuel?) so it could well have been pretty light, and even if not, I suspect A139 power margin is good with 4 POB.
NRDK - I'm not convinced engaging all appropriate upper modes on a 4 axis is necessarily the best way go here. To be fair I've not flown 4 axis, but I can't help but feel you've got to be a lot cleverer to be absolutely sure the automatics have all been properly set up and then tweaked - and if they haven't, well, that really will stuff you. I'd have more confidence in just maintaining that hover attitude in the climb by hand. A number of accidents have come from over reliance on automatics, and under-practiced hand flying, as we know.
76fan and B Bob - glad you raised night rig departures. No experience but I had assumed that in reality many of these must towering instrument take offs. Surely there are often no visual references at night? And to make it much harder, I'd imagine often at weights giving much smaller power margins than this 139 had.
Lonewolf - you may well be right in that the crew were in too much of a hurry (panic?) to get some fwd speed going and put the nose down too much, and then got disoriented. I suspect they could have been VMC on top (of the fog) at 150ft to make the transitioning job much easier, but even so a 10 deg pitch down is all that it should take - if you've got the power to climb well vertically there's no rush to generate airpeed - and if there is the chance of descending and disorientation with bigger attitude changes are much higher.
I certainly would only want to do this with a good power margin though - the briefer the climb the easier it is and less any drift can occur. I think I recalled the 139 was initially going into Coventry 20 mins away (for fuel?) so it could well have been pretty light, and even if not, I suspect A139 power margin is good with 4 POB.
NRDK - I'm not convinced engaging all appropriate upper modes on a 4 axis is necessarily the best way go here. To be fair I've not flown 4 axis, but I can't help but feel you've got to be a lot cleverer to be absolutely sure the automatics have all been properly set up and then tweaked - and if they haven't, well, that really will stuff you. I'd have more confidence in just maintaining that hover attitude in the climb by hand. A number of accidents have come from over reliance on automatics, and under-practiced hand flying, as we know.
76fan and B Bob - glad you raised night rig departures. No experience but I had assumed that in reality many of these must towering instrument take offs. Surely there are often no visual references at night? And to make it much harder, I'd imagine often at weights giving much smaller power margins than this 139 had.
Lonewolf - you may well be right in that the crew were in too much of a hurry (panic?) to get some fwd speed going and put the nose down too much, and then got disoriented. I suspect they could have been VMC on top (of the fog) at 150ft to make the transitioning job much easier, but even so a 10 deg pitch down is all that it should take - if you've got the power to climb well vertically there's no rush to generate airpeed - and if there is the chance of descending and disorientation with bigger attitude changes are much higher.
Lonewolf - you may well be right in that the crew were in too much of a hurry (panic?) to get some fwd speed going and put the nose down too much, and then got disoriented. I suspect they could have been VMC on top (of the fog) at 150ft to make the transitioning job much easier, but even so a 10 deg pitch down is all that it should take - if you've got the power to climb well vertically there's no rush to generate airpeed - and if there is the chance of descending and disorientation with bigger attitude changes are much higher.
For night IMC, I'd call that an unusual attitude at the very least ...
Disorientation is my best guess at this point.