Offshore Rig/Elevated Deck Takeoffs in Bell 212/412's
 

Current coffee break discussions have revolved around the "preferred" method of departing an offshore helideck or elevated helideck in a twin engine helicopter. One school of thought suggests a level acceleration to best rate of climb airspeed then a climb to a safe altitude whereas the other school of thought is to accelerate at a level altitude until the best angle of climb airspeed is reached, then climb at that speed to a safe height and then accelerate to the aircraft's best rate of climb airspeed. The first method is described as being "better" because it shortens the amount of time the aircraft is within the shaded portion of the Height/Velocity or WAT curve, whereas the second method is thought better because it provides more height above the water sooner, so as to improve the chances of accelerating to best rate of climb airspeed without making contact with the surface following an engine failure.

Major concern for this discussion involves low-height decks (i.e. 50 feet above surface) and the possible contact with the surface which might result while trying to accelerate and fly out of an engine failure at the most critical point of the takeoff...assumed to be just at crossing of the deck edge.:confused:

Hover yourself over to deck edge so the rotors are overhanging. Into as much wind as available. Check all limits OK. Pull power and head upwards, then rotate off the deck. It now depends on if you are day or night.

Day accelerate to 60 kts and climb. Night accelerate slower climbing and accelerating at the same time.

So I suppose both your answers are correct, one for day, the other night.

By pulling power over the deck if anything fails you'll come straight back down on it. Or after rotation if an engine fails just after you aren't going to hit the tail on it.

Most decks are over 100 feet for major platforms. Smaller platforms can be 50 feet. If something fails just after rotation pull maximum single engine, aim at the water and get some airspeed!!! :)

Did you consider that the HV curve is a limitation and not to be flown into at all?
Check the flight manual for those two aircraft (unless you have a Flight Manual Supplement for a cofiguration with less than 9 passengers) - the HV curve is in the limitations section.

Second part of the question might be- why not follow the Category A profile?

Lessee here Shawn.....if I creep the thing up to the edge of the deck...or scoot off over the edge...if my memory is anywhere near correct....I am unfortunately in the shaded part of the WAT Chart no matter what I do...and if the aircraft has more than nine pax...or seats for more than nine....and even if I use Cat A as you suggest....me thinks we still have a problem....am I correct in assuming that? Now does the WAT chart only apply to takeoffs over firm, smooth, surfaces....which oceans are not....gosh...maybe there is no legal way to make an offshore takeoff.

Can you enlighten me just a bit more here , Shawn? But of course we must never violate the limitations section of the flight manual while aviating....got any suggestions, flight profiles, weights, airspeeds, or something that will advance this thread, Shawn?

There is a difference between the WAT chart limits and the HV. Hopefully you are well clear of the WAT chart anyway - the HV is the one that's difficult.
And you are right, there isn't a lot of help in interpreting the charts.
The 9 passengers or less limitation is on the configuration, not the number of seats you have occupied. You can see this in the change in the HV location on the BK-117 when it goes to a high density seating configuration - the HV curve moves to the limitations section of the supplement. S-76 with the less than 9 pax supplement has the HV curve in the performance section.
The problem is that most of the helicopter community doesn't understand that Part 29 helicopters are supposed to offer the same level of safety as a Part 25 airplane- that's why they are in that category instead of Part 27.
Which brings me back to my original question - why not use the CAT A techniques and performance stuff- the profiles are pretty straightforward, not much of a performance hit, and guaranteed to be able to fly away or land back if the engine fails?

Shawn,

I think the basic response is that operators have to provide as many seats as possible....and Cat A vice non-Cat A translates into 1-2 paying seats less per takeoff. It is also probably fair to state that oil companies usually give mere lip service to safety and revert to the Risk management mode when calculating safety costs....as compared to operational costs.

An example, a rather well known oil company and a large helicopter operator agreed to compromise on reject areas after selecting Cat A standards for their Bell 212 operation. One of the compromises included the approval for the operator to use canals and rivers as an authorized rejected takeoff area following an engine failure on takeoff from land based helipads. The decision was predicated upon the cost of preparing long, smooth, firm, and even landing surfaces for the aircraft. The Cat A takeoff profile itself was altered to provide some semblence of a normal Cat A profile to fit the very short dirt reject areas available. No thought was given to reducing the takeoff weight (based upon seating) during this process. The good news is .....to date there has not been an engine failure on takeoff that required an intentional reject into the water on that operation. The modified Cat A takeoff profile placed the aircraft smack in the middle of the shaded area of the WAT Chart....and was merely an old style US Army confined area takeoff over barriers 150 feet high...that is ...up, up, and away on a nice angle to 150 feet with a reject area as short as 250 feet. The profile seemed to work...but the thought of landing in the water as an approved reject area sure seems unwise to me.

Just out of curiosity, if a good amount of power would be available departing the rig, how much vertical distance should you take above the deck before rotating?
What's the common practice out there?

"Back Up Departures"?
 

Any one using a variant of the approach/departure Point-in-space technique?

The departure profile, common in the States in the EMS market, would be to apply sufficent power increments to vertically clear any nearby obstacles.
Then with slight increases in power, and back pressure on the cyclic, work away and back from the touchdown zone, until you reach a height of 150' to 200' above the ground/deck. Upon completion of a power assurance check, gently accelerate the airframe, without losing altitude, until you reach Vy.

It offers an opportunity to execute a sinlge engine procedure back to your departure point with minium ammounts of control input, power changes, and pitch attitude changes.
Perhaps it has more relevance in the confined areas which most EMS types work within, and their lack of appropriate F/L options.

Kevin

Cat A for a 212 from a rather old manual I have in front of me takes you backward and upwards to 160 feet. Initially straight upwards to 40-60ft.

In reality on a good day, hot and heavy your 100% TQ will get you max. 30 feet (more likely 10) above the deck when fully loaded..... and without a wind straight back down on it.

Thats all within weight limits and offloading payload above 22 Celsius.

So as you leave your deck, your tail will clear the deck should an engine fail. Now you have 110-130 feet to get to an airspeed to climb away.

I guess I'm a bit surprised by some of things coming out here. First of all the takeoff profiles on a modified Cat A procedure should have been approved by the operating authority not just the helicopter operator and the oil company. Anything less than authority approval will leave you wide open for some pretty damning lawsuits.
I'm also very surprised that a Bell 212 at maximum weight cannot hover more than 30' AGL at sea level in warm conditions. I'll have to consult some performance stuff I have buried elsewhere, but at first glance it appears to me that it should have plenty of power reserve in those cases. Has anyone checked the weight to ensure you are within limits? remember that if you overload the machine, you invalidate the Certificate of Airworthiness....

Ahhh....land v. sea?
 

Perhaps the difference rests within the element of this technique that you are NOT seeking a flyaway speed with the CatA backup departure.

Once you've cleared the initial obstacles which may impede the capacity to alter the nose of the craft, you gain the ability to alter the direction of the nose of your craft in order to better utilize the relative wind speed available that day.

The wind speed, the more the merrier, actually allows you to better manage your power buffer and back away bit by bit. It is by NO means a rapid response technique.

Should the worst happen, mechanical or met, you have the capacity below 150'(approx.) to execute a single engine approach right back down onto the helideck or LZ dependent upon relative surfaces.

Sorry, not meant to be confrontational, just conversational....
hope this is a better job of restating the concept?

Kevin

Shawn; I don't know if the 212 transmission limits are any different these days but I spent a lot of time in the mid-1980s in a rather hot and swampy place having to pedal turn on takeoff in nil wind simply to clear the deck, and we were pretty confident about the weight being at or just under maximum. 30 feet wasn't often an option!

I'm a bit surprised at the various ideas put forward for this interesting question. Helicopter offshore operations have been in existence for many years and the 212 for over 25 at least. Nearly all companies I've flown for use this basic tecnique.
1. Low hover at front of deck with blades NOT overlapping to build up ground caushion. Position can vary due to deck design & the turbulence you're getting.
2. Apply full available power & climb vertically.
3. At 20 feet radalt (15 feet minimum )for most medium size helicopters, while you still have a POSITIVE rate of climb, rotate fairly positively to about 10 degrees nose down. ( Can vary slightly with c of g )
4. If you can't reach this height, you are too heavy.
5. CDP is the point of rotation. Engine failure before rotation, land back on. After rotation, maintain collective position for transient time if nessary, while looking for VToss, level off and accelerate to VBROC.
6. By having 10 degrees nose down, your tail should be well up and clear of the deck.
7. This works by day or night. In fact you can do this all with your head in the cockpit looking at the instruments and is not a bad method to demonstrate to an unbeliever.
8. This method has worked well for me for over 40 years both in the cold of the Antarctic and the heat of India.
9. Obviously if the helicopter is very light and you have a strong helpful wind, you can modify this. Never make rig work too black & white.
10. Tearing along the deck to gain airspeed is very much a no no.
11. Now watch me be blown to pieces!!:rolleyes:

for shawn coyle
 

What's a modified Cat A???

I was taught a Cat A is just that....anything else may be a company approved procedure or a pilots own choice, at his discretion.( Cat B?)

Thanks!

Here Here Nigel... ;)

just admit it, you love'd India?

Yeah, but what about....?
 

Being a theorist and not a pilot I open myself to some flack on this but I will repeat what I stated in a post I made a long time ago. This post is in response to the advice given about hovering the helicopter to the edge of the flight deck placing half of the disc in ground effect and the other half out of ground effect.

Many years ago a group of US Marine HRSs (S-55s) did just that only in this case the back ends of the helicopters were hanging over the ocean which was 80 some feet below. When they successively pulled collective they fell backwards one-by-one into the ocean below. A lot of people told me I was full of it and said it was impossible however it did happen and they lost several helicopters in the process. It is similar to hovering above a moving ship and letting the ship move out from under you. When the ground effect of the flight deck was no longer there the helicopter in which I was riding almost fell into the water until the pilot regained positive control.

:eek:

Nigel

Well the technique used here is exactly as you described except we hang the rotors over the edge of the deck. I think you have just explained it better.

At night our preference is towards more level than 10 degrees nose down. Just preference for altitude over airspeed.

Shawn

Max Gross is 11,200 and start lowering from 22 Celsius upwards. From 25 degrees it's about 60-70lb per degree. 38 Celsius will allow you 10280. Temperature, higher of ground or 1000'

Lu

I can understand falling into the water backwards when pulling power with your tail over the edge of the deck but not if you are into wind. If into wind you normally will gain an updraft when at deck edge.

Retiring back behind my stone for cover........

Guys........get it right before your OEI in a critical phase occurs....!!!!..or it will hurt.

Good to see old Nigel has found the pump for his wheel chair tyres....

Remember the Oil Platform is a thing to avoid at all costs if you have anything except both engines running wide open..!!!


From a purest point of view,yes the HV curve is in the limitations section....however remember......BHT also tolerate, Winching, Slinging, Longlining and Oil Patform T/o and Landings......

Cat A......geee guys........There is NO place for Cat A is todays Oil Operations......remember what Cat A is designed for..???...

*To ensure a safe OEI reject or safe flyaway after an OEI event for a specific known take off distance.....and reduce the T/O Wt until that performance can be achieved.........and the relevance to Offshore..?.....not much.

A safe departure?.....as per old Nigel......however a 15 nose down or attitude change would be nicier........and there should be no difference for your night verses day technique...remember your Nr droop doesnt know the time of day....nose held down until your airspeed is alive then reduce your nose down attitude......remember its better to be closer with the surface [water] with a healthy Nr and close to Vtoss than at 150 ft with the low NR warning on and no IAS.......farewell indeed.

The suggestion of backing back off an Oil Platform is horrific....in the OEI configatation the oil rig is your bitter enemy....better the water than an impact on the deck [hovering auto excepted]......once CDP is reached at around 15 feet....15 nose down and get out of there.........

OEI before the commited point on approach.....get out of there...overshoot.

Keep your Nr UP.

PS.....Move to the deck edge.......Rotor tips inline with the edge.......not over it........

I agree with Nigel and red wine. Everything works fine with a deck at 100' or so above the drink. If the deck is lower, say 50' as previously mentioned or on a ship, then you have to ask the question: if I continue to climb vertically to gain enough height to fly away OEI after rotating, how hard might I hit the deck OEI if I abort prior to rotating. Depends on almost everything, and if OEI ditching or hard landings are not an option, pay the dough to load real light....

Mixed signals.
 

To: Rotorbike

Although not totally conversant with the entire situation I can only report the facts, as I know them. There had to be a strong relative wind flowing across the deck from stem to stern due to the ships' movement through the water. And, there may have been as you indicated a strong updraft, which may have caused a confusing, wind state with the updraft mixing with the longitudinal flow. This was coupled with the possible lift differential across the rotor disc caused by one side of the disc in the stable airflow while advancing and the other side of the disc in the confused airflow while retreating. If I could, I would place a very large ? at this point. Is it possible that it was due to a flap/blow back situation caused by the strong airflow across the deck (20-35 Knots)?

On the present helicopter carriers (LHA) the helicopters and the Harriers are aligned with the centerline of the ship however on the CH-53s a part of the rotor may be over the side but then again the CH-53s have more than adequate power where the HRSs only had 600-700 Horsepower availavle.

:confused:

Rotorbike.
The problem of being at the deck edge is that you lose your ground cushion. Assuming you wish to be at max weight for that flight, you will need more power which by definition is not available. Also depending on the deck design, i.e. is there an accomodation block below?, any wind above 10 knots could give you unpleasant turbulence which by being further back and climbing to 20 feet could possibly keep you out of it.
Red Wine.
Enough of the "old" ! There's nothing wrong with my wheel chair!Using 15 degrees when at max weight tends to lose height faster than you are gaining airspeed whilst still over the deck. Once clear or if light, by all means go to 15 if you have sufficient height to play with.
Coyote.
Using the same technique day and night gives greater consistency of performance plus the non flying pilot will know exactly what you are trying to achieve. Level take offs just because you are low is not the best way. The deck height doesn't really matter; you adjust your weight accordingly to get the performance you need. At low level, speed is generally more important than height. Look at HV charts. Losing an engine at 60 kts at 50 feet is not a problem, try doing that in a 50 ft hover.
If you do lose an engine seconds after rotation, then you will need more than 10 degrees, possibly up to 25 degrees height permitting. At this point you are looking for speed, not altitude.
Bit hard to explain without having a helicopter to demonstrate what I'm trying to say!:D

All the speculation on best OEI procedures is interesting, but without test or an approved procedure it is all just speculation.

A vertical rise above the deck with a nose down acceleration is the only way to assure avoiding striking the deck edge if an engine quits during the takeoff. How high to go depends on the aircraft, weight and OEI power left, and is not one-height-fits-all.

The most critical time in an elevated deck takeoff is the first few feet, where you most get clear of the platform and netting. A failure there is nearly catastrophic, with a tumble down to the sea likely while just half off the rig. Any procedure that cuts your time there is the best one. We do a vertical procedure in zero exposure operations, which means going up to a height above the pad, then diving to clear the pad lip. If loaded to the wat curve, a failure anywhere during the takeoff results in a landback or a dive away and climb. The critical measurement is tail clearance from the rig during the OEI dive away.

The actual exposure time is only about 5 seconds or so, and the probability of engine failure in that tiny window is truly nil. For the T700 family, the US Army experiences 1 failure each 500,000 hours of operation, so if the 5 seconds of exposure were repeated each hour, and you fly 1000 hours per year, and you have Cat A stay-up ability otherwise, the probability of an engine failure occuring to you during the takeoff exposure window would be about 0.000000000005. Typical rig engine failure experience bears this out.

We debate engine failure, practice for it, work like fiends to polish the procedures, and meanwhile ignore the common fly-into-the-water cause of 1/2 of our fatal mishaps! We are like some ancient religion praying to the engine failure god while each night another beast comes along and steals our best. We don't even recognize his existence!

See the OGP report for a summary of fatal accident causes for twins offshore. 45% is CFIT, 22% Mid air, 22% control problems. Let's debate the real causes, not just the ones we can practice!

http://www.ogp.org.uk/pubs/300.pdf


Nick

I had a single engine failure in a Bell 212 just after rotation, going off a helideck on a drill ship in Egypt many years ago. It was around 38 degrees C and I think I was around 10600 lbs. We used to use the technique of rotor tips just inside the deck edge, pull hover torque + 15% (or full power, if less) and rotate at 10 feet or when RoC started to fall. The engine failed just after rotation, then caught fire and the deck was around 50 feet elevation. I used nearly 15 degrees nose down, avoided the deck edge but was still only just over 30 knots at around 10 feet. However, the good old 212 did mange to start climbing shortly thereafter and got us safely back to shore. The Nr was pretty low though (around 85%). I don't think a low inertia rotor rotor machine would have fared as well.

soggyboxers,
That was the proverbial worst case failure all right. What was the cause of the quit?
Nick

Shawn,

I described the "modified Cat A" takeoff in my post and for a quick repeat....the operator and the oil company mutually agreed to the modification and led the local DCAA to believe all was well. Thus your concern with compliance with the letter of the law was taken care of.

The salient point of my post was to take issue with the idea that accepting a rejected takeoff to a river or canal constitutes knowingly and with malice aforethought....what would in any other situation be known as an "emergency ditching".

That decision was predicated upon the customer's objection to spending the money required to bulldoze and grade the appropriate area for reject areas while at the same time claiming to be using Cat A performance.

As a Test Pilot and Instructor of Test Pilots, I would think you would be more immediately concerned with actual performance versus theoretical performance, and constructing your test flights to conform to test parameters in order to be able to determine if the aircraft is operating as designed or expected.

To declare the use of rivers and canals as reject areas flys in the face of the normal criteria used to define reject areas....ie..firm, smooth, even surfaces.

Last time I checked...4-5 degrees above the equator at sea level and an average temperature variation of 30 degrees C plus or minus 10 degrees...water remains unfirm .

So, Shawn....what's a working pilot to do, when confronted with such issues....letter of the law met, company SOP and Ops Manual dictates the procedure, checkrides require compliance, and the whole time, both customer safety staff and company safety staff sign off on the procedures?

Or...am I completely missing the point and intentional landings in a river or canal while conducting Cat A operations with emergency float equipped aircraft are both safe and acceptable under the constructs and criterion for Cat A operations? (as defined by that particular DCAA, oil company, and helicopter operator)

Sasless,

The point of view that "knowingly" operating without full Cat A capability is some how wrong or unethical is baseless, and Shawn (a friend and a very capable guy!) knows that too.

Operating rules are in place that allow limited exposure to engine failure in virtually every place on earth (does anyone know of a requirement for Hard Cat A in commercial oil operations?)

If a sudden requirement for hard Cat A were implimented, the operating world would stop, and safety would not improve to any measurable degree. There is much controversy brewing as the JAR Ops requirement clock ticks down, and also some rumor of ICAO adaption of that standard (these rumors are not true).

Engine failure is not our problem, not according to our history, and the blind implimentation of hard Cat A criteria would actually hinder the improvement of safety (because it would spend money and regulatory horsepower where it is not needed, and divert same from where it is.) See my above post for the pointer to the real data.

Keep plugging, Sasless, Shawn, let's rumble!!

Nick

Nick,

I understand your concerns about the adoption of Cat A requirements by ICAO and JAA. My position was....and is....the claim was to be operatiing under Cat A when in reality the decision to withhold the proper reject areas in actuality made the operation non-Cat A. The point being....call it what it really is...non Cat A with all that means.

With the JAA/ICAO crisis coming....maybe the old Wessex with twin Gnomes will become in vogue again!

SASless,
There has never been any deception about Cat A procedures and exposure windows at rigs, the issue has been known and understood since the beginning by regulatory agencies, operators and manufacturers. Welcome to the group, Sasless! There were even modified Cat B procedures to allow zero rate of climb enroute, and add a few hundred pounds more payload, with full CAA approval.

What I am concerned with is the blind adaption of a requirement because it is "complete" or "neat" without a real justification, while ignoring the real causes of accidents (why not mandatory EGPWS?)

So, let's declare all offshore helos obsolete, toss them out and replace them! I am sure that money spent on new helicopters is just laying around out there, unspent right now and available. It will not mean any reduced operating budgets, fewer aircraft, fewer contracts. It will not make fewer jobs. Of course, all that is not true, it will cost all other parts of the industry to suck up the differrance. What can be said is that it will NOT cause any measurable rise in offshore safety. That is guaranteed.

It is in the best interest of my company to support the new operational requirements, since the S-92 is "hard" Cat A from a rig with full pax and enough gas to go about 350 NM with JAR reserve.

Nick,
My engine fire and failure was caused by the engine oilf filler cap coming off after the retaining nut on its locking plate sheared off. I'd been flying for about 3 hours on a crew change at the time.

Oil Rig Take-Offs
 

Under FAA we are allowed to violate the H/V limitations during an offshore take-off or landing by 14 CFR 91.9(d). PHI has had the H/V limitations removed for all Transport Category Rotorcraft (Part 29) at PHI.

Jack

offshore helideck design
 

I would like to have your opinions about an offshore production platform helicopter refuelling installation.
To make it short,the flare on this rig, is obviously too close from helideck and its fueling system, the radiating temperature on the deck surface is commonly measured at 47°C and is about the same on helicopter skin after a short st.by. Depending upon the wind, small drops of burning crude oil spill everywhere in the vicinity, a shield of (salted) water doesn't change these figures a lot.
Untill now we are not happy to approve this new refuelling installation and to stand by here but we cannot find any regulation dealing with this matter.
The platform's engineering service keeps telling us there is nothing wrong in their design.
Does somedy here knows something about this ?

Waiting your answers before everything ends up in ashes

Thanks !:{

CPT..............
 

Look up ICAO Annexe 14.................

If you have an incident/accident.......please be assured your Insurance Company will know every aspect of Annexe 14 that you decided not to enforce.

Thank you for your answer "old man rotor" but on the ICAO 14 doc I have, there is nothing about refuelling installations and minimum distances from open flames ( as with a flare). It's just our common sense that tells us it's too close and too hot for a safe refuelling.

Ok....give me a few days and I will hunt the reference up for you......

However I can't remember any reference to the flume of fumes, heat, flares or smoke etc.....

But certainly to the 180 degrees approach and 150 degrees 5:1 drop off ratio on departure....

Also the splay outward from the side of the "D" value.......lights, markings, fire equipment etc.


The UK have their own reference to ICAO Annexe 14.....from memory its CAP 243 or 432.....maybe 342...Bingo.!!

I will do my best to dig into my files for you.

Can anyone help with the correct UK CAP??

CAP 437
 

CAP 437 - Offshore Helicopter Landing Areas - Guidance on Standards

I'll come back with more info shortly.

CAP 437 states that when helideck temperature rises by 2ºC over the ambient temperature, the BHAB (British Helicopter Advisory Board) should be notified.

BHAB is the body in which the CAA discharges its regulatory responsibilities regarding offshore helidecks. Therefore, BHAB is the authority in this respect.

I used to inspect helidecks on behalf of BHAB, and in most cases when there was a rise in the helideck temperature it was due to hot exhausts. In any case, there was never a difference greater than 4ºC. In such circumstances the procedure in place was that radio room should pass on to the helicopter both OAT and helideck temperature, so that the crew were aware of the possible loss of performance once close to the deck.

CAP 437 also states that cold vent, exhaust and flare systems should be designed to terminate and discharge at a location on the installation as far from the helideck environs as possible. The potential release volumes, flammable concentration, and dispersal characteristics should be quantified, so that -if required- a 'no fly zone' around the hazardous area could be applied.

By the sound of it, the standards in the installation you mentioned above are nonexistent.

If you need more information about CAP 437, please let me know.

PS: There is a set of comprehensive studies (M E Davies - 1977 to 1979 - Local atmospheric environment of offshore installations), which was used at the time of amending CAP 437 in 1998. I don't have access to it now, but I guess it could be a very valuable source of information.

Cpt

Send me your e-mither adress and I will let you have acopy of Civil Aviation Publication No 437 (CAP 437)

What is the geographical location of the helideck (governing Authority)?

Many thanks for your answers, my email is [email protected]
This helideck is located in the Gulf of Guinea and the governing Authority here doesn't say much about helicopters in general, therefore we use to comply with ICAO or country of registration regulations.
Until now we don't intend to use this refuelling facility but it is embarassing not to be able to show a regulation who could help our customer to solve this problem.

CPT.....
 

Just be aware that ICAO 14 gives guidance to all member states [countries]...........

States can then vary the standard Annexe 14 with some of their owns rules and standards.....hence the UK call their equivilant of Annexe 14, CAP 437. The US will have theirs and so on and so on....

By the sound of your area of ops.....who knows what standard would apply.

Offshore "Point in Space" IFR approach
 

POINT IN SPACE (offshore) IFR approach

(Offshore Cloud break procedure)

We currently have a small dilemma here in China which I would like to see rectified. We have CAAC approval for the standard NDB/ARA approach to the rig , albeit to slightly higher minima. This serves us well for the outbound trip.

Inbound , if the weather is really ugly then we have access to an ILS at destination but it requires some extra off route flying time.

Our track from the field to helibase (which is for all practical purposes , on the beach) , takes us over a small island located 5 miles offshore (highest point 600 feet)
Invariably ATC has us descend to 1000 feet and report that we have this island in sight before he will give us clearance to make a VFR approach. Fair enough.

The “ugly” weather here in the tropics is very rarely cloud base below 500 feet. (Visibility is another matter. When the rain starts it can drop the visibility down to damn near zero.)

For those days when the Wx is not ILS ugly (but am in cloud at normal cruising 2000 feet) , I would sooner letdown , on track to say 500 feet but 5 miles back from the previously mentioned island and motor in to say 2 miles (Chinese VFR requires 1.6 nm vis). If I cannot see the island at this juncture then it is time to turn around and request clearance to the ILS.

This let down as mentioned above would be with the aid of NDB , DME , GPS and Wx radar.

When I was with Shell Brunei many moons ago , they had a “point in space” approach that allowed just such a let down.

Now here is my request from all you folk out there. I have a better chance of getting a CAAC approval IF I can show that other civil aviation authorities regularly give such approvals to IFR heli ops.

Could you please send me your ideas but better still your “point in space” cloud break procedures if you have them.

Tanks muchly

Peter
:8