Night offshore landings: a new approach?

[Aser]

DB, I sent you an email with the request.

Regards
Aser

[bondu]

Re Winds of Change

DB,

You are so right when you talk of the Oilys concept of "if there's doubt, there's NO doubt"!

I think most of the NS pilots will agree that we will always try to complete a crew change flight, but we must always remember that we are only taking people to work. We are not SAR crew, doing our utmost (safely!) to save lives: we are, in effect, highly qualified and highly trained bus drivers.
All the advances in a/c technologies, better SOPs and stricter regulations will be of little use if pilots continue to be subject to 'commercial' pressure, whether from the client, company Operations or indeed self-imposed.
That's not to say that all those advances shouldn't be made and introduced; they should, and probably should have been introduced ten years ago!

bondu

[Geoffersincornwall]

Crab

Nobody that I know harkens back to what you refer to as the 'good old days'. That's your interpretation. not mine nor I suspect others that have pointed out that progress to standards we enjoy today came at a price and that price was paid by our colleagues and the pax we flew. Believe me there is nothing to enjoy about those days but it is, I believe, worthwhile reminding folk that once upon a time we thought it was OK to do things in that quasi-military fashion but now we look on things differently. This lays the ground for accepting that DB has made a resoundingly good point and once again there is the opportunity to put the bad old ways behind us and get with the standards that the rest of the (CAT) aviation world enjoys.

I've said it before and I'll say it again, extended flight with the skill meter at max is just inviting disaster.

G

[T4 Risen]

DB,

Thanks for sending me a copy of the presentation. Very well put forward and makes the point quite clearly.

One of my concerns with the current situation is, that there seems to have been a reduction in later flights during the winter months. As a result we do not get the practice and continuity that we need to fly either the current approach techniques or the ones you are proposing.

Why not role this out as "THE" procedure for day/night /bad weather/good weather.

I know there will be moans of "its not commercially expedient" and "it will result in more flights not completing". But surely if it means more hours in the air, it means more revenue for the heli operators? I am sure the safety concious oil companies would could be pursuaded to use a little of their billlions of £ of profit to help improve safety!!

I think i said in a previous post, if this were to become the only way of flying an approach offshore then everybody should get pretty good at it very quickly. It then doesnt matter what conditions you are flying in, the sight picture should always be the same. And during that night in Autumn when you get called from your slumber on night S/B to go and pick up a medivac etc, having not flown a night approach since the previous December, you can depart with the confidence that you have made the same calls and followed the same sight picture a couple of days ago when you did it in the day time.

Just a thought.

T4

[helimutt]

All well and good saying the oil companies could pay for it, but just recently they are requesting a 20% reduction in costs from the heli operators to 'help' them through these 'difficult times'.
Funny they never offered us extra when the oil price was sky high last year???

[DOUBLE BOGEY]

T4

I think you are absolutley right!!! The beuty of a structured mandated approach is that it can also be practised (and if necessary mandated) for daylight approaches.

For all of you out there currently doing this stuff - I have never intended to imply that most of us are not adopting safe practises. Majority of the pilots I flew with have a procedure (sometimes guided in the OM) to carry out some kind of approach that is essentially safe.

The key problem is the STANDARDISATION of those procedures to facilitate intervention parameters and policies.

[AndyJB32]

night approach profile

Hello DB, thanks for the profile.

I sent you an e-mail back with my thoughts, but i'd be interested to see what others think.

I think overall it's got some good points, and it will certainly get us thinking and talking about how we do things offshore at night. A couple of things just on first reading though:

1. i think a 1.5 nm final is too far. I think somewhere around 1nm, 60 Kts groundspeed and 500 feet is ample. The problem with starting too far out is the potential for the crew to become fixated on the lights of the helideck/rig as they spend a long time flying toward an unchanging focal point (ie the rig stays much the same until you're a bit closer and can pick at a bit more definition).

2. The speed for the approach gate should be based on a groundspeed that will also ensure the ASI is above Vtoss (or Vy). This is for the same reason as point (1). If we turn into a 1.5nm final with a 55Kt headwind, by the time we get to the point of our sightpicture for the approach, there's a chance that the crew will have been staring at a seemingly unchanging focus point of light for long enough to become fixated on it.

I think the idea of simplyfing the night approach by making the visual and ARA identical is an interesting one.

I also think that at the moment the focus of the training department does not accurately reflect the type of flying we do - we have as much emphasis placed on doing a night approach offshore with a trainer as we do getting evaluated on flying the hold - 1 per year. I think the training should be focused more on the offshore night flying that we do.

Andy

[DOUBLE BOGEY]

Andy,

Your points are well made, but flawed (if you embrace the concept that Night VMC does not reallt exist).

The key to the profile is speed stability from the TOD to the CTB and IN ADDITION speed deceleration profiles such that the PNF has defined intervention parameters. This being the key fundemental to a monitored approach.

I understand you reservation about a 1.5Nm final, but WE ARE TRYING TO ENCAPSULATE THE ARA into one profile for all night approaches.

This necessarily means that the 1.5Nm "10 degree Offset Point" in the ARA profile must be catered for in the new profile.

In essence, if you look at the complete profile, although somewhat complex at first view, it is meeting all the ARA requirements, every time, on every approach.

To consider your suggestion, that a 1nm final such suffice, in essence if all your profile was trying to achieve was a night approach in VMC then it is sound.

You will see from the presentation that for shuttling (WX required at least 500 feet and 5 Km) we alleviate the FAG to the ARA MAPT, which prevents excess manouvering when rigs are closer together, but accepting that it will necessitate wider circuits than what are probably being done at the moment. IT IS A COMPROMISE FOR EXPEDIENCY.

My view is that all night approaches should be flown as a structured monitored approach in VMNC, which if flown when low cloud is present, IS EXACTLY THE SAME.

One profile, providing clear intervention parameters, supported by mandated intervention policy, that with a little practise becomes second nature.

I repeat, there is nothing wrong with your suggestion IF ALL YOU WNAT TO DO IS DESCEND IN AN UNCONTROLLED FASHION and land when there are no cloud.visibilty issues (I am deliberatley trying to avoid the use of the words NIGHT VMC cos I do not think it exists over the sea in the dark).

DB

[AndyJB32]

fair enough

I need a bit more time to look over the profile to see if i agree with you about the approaches being identical regardless of the weather at night time.

[JimL]

Thanks to DB for providing his excellent presentation; it is a good for a number of reasons, not-the-least-of-which is that it provides the basis for further debate. However, there has been little comment since it was made available so it might be a good time to look at some of the underlying conditions of offshore approaches so that we can explore what we might, or might not, be able to do to improve procedures.

If I repeat some points/assumptions from earlier posts, I apologise but it is necessary, in the interest of understanding the issues, to draw a number of previously stated points together.

Firstly, the ARA is a non-precision approach which has more in common with NDB procedures than the ILS. It also has less risk (with obstacle clearance) than onshore procedures. Some points about the ARA:

• Before the procedure is flown it is mandatory to ensure that there are no ‘targets’ (radar returns) in the final approach and missed approach segments. This ensures that there are no obstacles (apart from the surface) and those at the destination to consider.
• Onshore procedures constrain vertical descent (and DH/MDH) to ensure that obstacles are cleared vertically; the approach segment is also oriented so that obstacles are avoided laterally (it’s built into the profile).
• Offshore procedures are designed in the knowledge that the vertical extent of any obstacle may not be known; furthermore, it is likely that the highest obstacle in the area is the destination (hence the point about absence of targets in the final and missed approach segments).
• Offshore procedures rely entirely on avoiding obstacles laterally; for this reason, from the OIP, the heading/track has to be divergent to provide lateral separation of 3-400m to one side of the destination structure (even if the missed approach heading is applied later than at the MAPt).
• The MDH is no different to those onshore where, descent limitations should be plus 100ft minus 0 (based upon the RADALT – the setting of the baralt to RADALT is a wise option but only if checked as for normal procedures); these limits should be maintained until visual reference (see below) has been achieved or a go around, at the MAPt or before, has been commenced.
• The approach should be oriented into wind and flown at 60/90kts with a ground speed of no more than 70kts.
• The instrument procedure ends at the point where the pilot can proceed visually (unless there is a go-around at, or before, the MAPt).
• Visual reference has a specific meaning in most procedures; if one goes to Appendix 1 to JAR-OPS 3.430, and looks at the paragraphs that describe this for each type of approach (non-precision; CAT 1; CAT 2, CAT 3 and ARA) it can be seen that this is an important part of the procedure. For the ARA it says “No pilot may continue an approach beyond Decision Range or below MDH/MDA unless he is visual with the destination”. Without further guidance, that statement demonstrates a weakness in the regulation.

So far this procedure (as described) has been non-decelerative within chosen airspeed boundaries. For fixed wing it remains (almost) non-decelerative, the visual segment (in a stable approach) is a continuation of the approach path (be it on ILS or provided by the FMS or another device). This can be achieved because the glide path is continuous to the threshold and fixed wing land-and-stop as opposed to stop-and-land. There are other benefits of fixed wing procedures: the obstacle environment clears at the runway approaches; the aircraft is inherently stable; the field of view remains (reasonably) constant throughout the landing manoeuvre; either pilot can see and complete the landing manoeuvre from anywhere on the approach path. None of these necessarily apply to helicopters making approaches to an offshore installation.

Because we are approaching the highest obstacle in the area, there can never be a stable approach in the sense of fixed wing, and obstacle clearance has to be achieved laterally; unless the MDH is raised extensively (almost to the level of the height of the installation), there will always be a level segment. This level segment includes a ‘margin of error’ (at the OIP and MAPt) which dictates the location of both of those points; improving the accuracy of positioning of the MAPt (or using a fly-by offset procedure) can move it closer to the destination.

In my view, the actual cloud break procedure is not the key issue – safety benefits from having vertical guidance are nice to have but not critical. The stability of the approach from (when visual) before, or at MAPt is the key issue (if it is just a matter of keeping a speed and height, it is easy to achieve and monitor). The key issue is in having both crew members briefed and/or aware of the envelope that is to be flown (and flying it). The level segment terminates at the point where the slope to the landing manoeuvre is intercepted. The flight path conditions at this entry point (or gate) will be dependent upon the height (distance) at which it occurs.

Let’s construct a flight path: Using a 3° glide would put the helicopter 220m back from the platform at 40ft above the deck (from which point the level segment of the standard landing manoeuvre could be initiated). Assuming a 150ft deck (which is 50ft above the mean deck height of the North Sea) distances would be:

For a 150ft deck and 3° glide, the distances back from the helideck would be:

• 40ft above the deck (190ft amsl) would be achieved at 220m
• 150 above the deck (300ft amsl) would be achieved at 872m
• 250 above the deck (400ft amsl) would be achieved at 1,454m
• 350 above the deck (500ft amsl) would be achieved at 2,034m

For a 150ft deck and 6° glide, the distances back from the helideck would be:

• 40ft above the deck (190ft amsl) would be achieved at 100m
• 150 above the deck (300ft amsl) would be achieved at 435m
• 250 above the deck (400ft amsl) would be achieved at 725m
• 350 above the deck (500ft amsl) would be achieved at 1,015m

The steeper the approach the longer the visual segment (my experience is that pilots are more likely to fly a 6° approach than 3°). I would also like to see what deck ovality is achieved with these approach angles – intuitively my feeling is that the shape on the presentation for ‘too low’ might be 3°, or even 6°.

Up to the slope intercept, we should have stable conditions – i.e. level flight, and a set speed (ground speed no greater than 70kts is recommended in the procedure) and monitoring and crew interaction is relatively simple. If the cloud base is 300ft at night, the intercept point will be 872m with a 3° slope and 435m with a 6°. Either of these intercepts might require a(n announced) deceleration (depending upon wind) but at least it would be in level flight – i.e. monitoring could be relatively easy.

Once on the slope, the NHP will see less and less of the deck until, by 40ft, nothing at all will be seen and further monitoring could be quite difficult. The speed the approach is flown will be dependent upon the wind speed; with light winds, there might not even be an indication of airspeed once the helicopter has decelerated below 40kts. Any monitoring will therefore to be based upon a floor of deck-height plus (say) 50ft and the (minimum) speed that has been declared for the approach (with a probable minimum of 35kts). If either element of this combination is called by the NHP a response would be required from the HP – no response would indicate a loss of control situation and an escalation in the procedure.

In my view, the key to safety is stability; on an ARA the aircraft should be stabilised (height, airspeed and heading) before the MAPt. If there is to be a circling manoeuvre, the aircraft must be stabilised before MAPt (at least 500ft, airspeed and heading); following on from that, night shuttling should be stabilised (at least 500ft, airspeed and heading) at the equivalent of the MAPt – which means any necessary turning must have been carried out and the aircraft stabilised before that point (as there is a requirement for 5km visibility, this should not cause any control/stability problems). Monitoring (up to the slope intercept) should be based upon a declared height of the level plus or minus 100ft and the declared airspeed plus or minus 20kts; any departure outside this envelope should be called by the NHP a response would be required from the HP – no response would indicate a loss of control situation and an escalation in the procedure. In the level segment, any bank of more than 20° or any undeclared departure of more than 20° from the heading should be called and invoke a similar procedure to that above.

I totally agree with DB that once a stable level segment has been set, there should be no descent until the slope is intercepted. There is no necessity for an offset to be applied with night shuttling as the destination will always be in sight and no missed approach is envisaged. A go-around should be performed at any time when either pilot considers that control is being lost or there are insufficient visual cues (the go-around should be discussed extensively and practiced – from the blind side - on periodic training). The use of automatics should be encouraged for all segments where stability is required.

Comments are anticipated.

Jim

[SASless]

JimL,

I am sat here with a real dose of St. Patrick's Day Remorse....but by golly it was a good time last night!

I found your post to be well written, thoughtful, and most agreeable in concept.

Now comes the "However but", where do we come up with weather minimums for offshore non-precision approaches that use onshore precision approach weather minimums (or way lower even)?

Why do we not apply proper "Non-Precision" weather minimums to what are by any definition "Non-Precision" approaches?

The MDH is no different to those onshore where, descent limitations should be plus 100ft minus 0 (based upon the RADALT – the setting of the baralt to RADALT is a wise option but only if checked as for normal procedures); these limits should be maintained until visual reference (see below) has been achieved or a go around, at the MAPt or before, has been commenced.

DB has done a very good job on his presentation.

The absolutely key point he made in my view is putting definition into the profile so the non-flying pilot knows what the flying pilot should be doing....and when a variance is seen....knows how to respond.

He used ten seconds as a time interval and I would suggest striking that and leaving it at "upon flying pilot's failure to correct" to be the intervention point.

If the check call is made, and the flying pilot does not respond correctly...both verbally and physically...then it is time to take the proper corrective action and not wait for a prescribed time period.

The key to DB's concept is improved communication and having a standard to work from.....he is spot on in that regard.

[DOUBLE BOGEY]

Wx Minima

It is very easy to get sucked into the whole "Weather Minima" debate. But really WX minima has F**K all to do with night approaches.

Night Approaches offshore, as described in my presentation, is about getting to the right point in space, stable (which means at least a sensible airspeed), and a height suffiecintly above the helideck to allow the reamining speed to be reducing in the final descent towards the deck.

To FORCE (to be frank) crews to get to that position we need to define a more appropriate MDH - AND THEN PREVENT CREW FROM DESCENDING BELOW IT UNTIL "THE REQUIRED VISUAL REFERENCES" are available. (my CTB)

The role that the actual WX plays, starts and ends at the MAPT. ie 0.75 Nm away from the deck way way before the CTB is achieved.

Forecast WX minima and actual WX minima play a greater role in the viability, or otherwise, of shuttling procedures.

Forecast WX minima plays an important role in pre-flight planning and the fuel plan in particular.

To confuse the role of WX with a procedure involving a defined horizontal and vertical profile is missing the point.

I have been very careful to "Encapsulate" the ARA into the night approach profile so that whatever the weather, the Decision Point (MAPT), IE CAN THE INSTALLATION BE SEEN AT 0.75 NM/MDH (Do I have Required references to continue) is absolutley not confused with the CTB....(Do I have required references to descend).

JIM L. I agree with some of your post but I cannot buy into the whole glideslope angle thing. The final descent towards the helideck from the theoretical CTB is actually more like 7 degrees...very similar to a Helipad landing as the ovality dictates the slope.

The only reason I compared the ILS with the current MDH for an ARA is to demonstrate the naiviety of the ARA procedure and highlight its key fundemantal flaw -

THAT 50 FEET ABOVE THE DECK does not promote a stable airspeed at the point that the theoretical glideslope (CTB) is achieved.

To be stable - THE SPEED IS WAY TOO HIGH.
To be able to land - THE SPEED IS WAY TOO LOW.

Move that sucker up and back by defining a more realistic MDH by increment above deck height and most of the problem is solved. WX at this point should have been delat with back at the MAPT.

SAS Appreciate you comments and support for the change.

Lets get the winds blowing.......In the right direction.


DB OUT.

[T4 Risen]

DB,

To take even more pressure off the crew why can we not push for an improvement in the facility off shore. how difficult would it be to install an Omni directional Chapi set up.

It gives a 6 degree glide slope and brings you nicely over the "H" at EGPD 23 at 20'?

T4

[Overt Auk]

T4 Risen: "how difficult?"

I hope to proved wrong, but in my estimation, very difficult.

On a 6 degree slope, to give 20 ft eye height means that the CHAPI need to be 200 ft beyond the deck. Might interfere with the 5:1 gradient a bit!

OA

[T4 Risen]

I am pretty sure that the CHAPI at EGPD is not 200' from the edge of the hover Square on 23 in fact it is more like 30-40' and the last time I made an approach to it we finished up at 20' radalt over the H.

I am not saying that we should use the exact design, which i believe was initially thought out by a north sea pilot. but something similar possably set into the deck or at the edge of the deck.

The more we have in the way of visual guidance the better....

T4

[DOUBLE BOGEY]

T4,

I agree, but I have heard that it very difficult to produce a robust system that is omnidiractional. Also what about moving decks???

I think AC Carriers have a gyrostabilsied set up but it only radiates downwind of the deck runway. I think it is luminous "BALL" hence my phrase "Calling the Ball".

Any carrier jock out there who can elaborate!!!

[DeltaNg]

Realism

There is a whole load of guff and abbreviations going off here. At the end of the day we want to land a helicopter safely on a rig, with a load of people reading newspapers in the back.

When I started flying offshore, I had less than 200 hours Total Time. Can you imagine how I felt when I was introduced to night flying later on that year?

Every Line trainer has his (or her) techniques and pet hates. And usually, it's done on an okay kind of night.

I remember asking the question, what is it like doing this off an ARA when the weather is really bad?

"Well, son, then you've really got you're work cut out."

Great.

From then on, it's a kind of learning experience, watching others do a few landings, and having a go yourself.

Some people develop the rigid gate concept. Other just kind of wazz about as if it is daytime, and can often be pretty good at it.

The scary thing was, there really wasn't any defined profile that could be pointed to in a Manual. Lot of ARA diagrams and ideal 'commital points'. The bit in between decision point and LDP is kind of up to you.

When you have 200 Hours - you really don't want to be making that bit up.

Nor does anybody, because nobody can second guess you.

Db's profile is going along exactly the right lines. It should have been done years ago, and will have absolutely no impact on the commercial aspect.

In fact, it will simplify the entire decision making process, and make for a far better, professional operation. As an ex-NS commander, I can see the benefits of this shining from afar.

It should be embraced wholeheartedly.

[DOUBLE BOGEY]

DELTA NG,

You will be appalled to know that very little has changed from the situation you described at the start of your career.

I think some Companies are slightly better than others, but the margin is not great.

Appreciate your support for change.

Fly safe

DB

[gnow]

DB,
Thank You for your presentation. It was very well written. I will give it a go when I do my Night Deck Landing practice next week. Here we hardly do any night landings except once every 6 months for currency only as the night standby is done by the 76 fleet. I would like to add one more point.... the night approach MUST always be carried out by the pilot with the obstruction on his side.
ARA approaches are fine for single one rig text book situation but when there is a cluster of rigs (and usually there is) and the one that you have to land is in the middle of the cluster and does not have a beacon it becomes a bit complicated.
I believe ARA is very useful for the North Sea where fog reduces visibility but does not have the violence of a tropical squall so operators in the tropics must be very alert for downdrafts and wind shear associated with a tropical squall.

[Shawn Coyle]

Firefly (the night approach lighting system developed by Richard Walker back in the 90's) theoretically could be hooked up to a datalink system to take the GPS position of the helicopter and change the 'on-glide-path' signal as the helicopter approaches the landing site.
Hasn't been done obviously, but as it has a light head that can be motorized for azimuth and elevation, it could be done.