Initial Report
The intial statement issued to us as operational pilots on NS is that nothing was wrong with the helicopter before it hit the sea.
The Commander has given his account of what happened and the crux of the incident is as follows:
The crew were attempting to approach the ETAP in marginal conditions, having descended to 300 feet.
They turned onto a final whereupon they became surprised that the platform was much closer than they thought. At this point the HP pitched the nose up (presumably to reduce speed). and the next thing they both knew was they had hit the water.
The impact seemingly does not seem to have been that great. However, the report goes on to say that the tail rotor, on contact with the sea, stopped almost instantly causing the TRDS to shear close to the transport joint. The driven end of which then flailed in the housing and all but severed the tailboom.
It is clear from some of the postings on this site that some people still believe it is a good idea to fly at night, without using automatics, relying instead on the superior flying skills to remain safe.
It is also clear that some NS pilots, flying older variants and types do not have the benefit of automatics at all.
It is also clear in the CAA Offshore sector, that once a descent has commenced VMC, there are no further rules to prevent the crew from descending as low as they like.
It is also clear that in many AOC Organisations OM procedures there is scant regard for the mandating the use of automatics at night.
It is also clear that on the ILS, the absolute minimum DH for a helicopter is 200 feet, this been the limit, stabilised, with full lead in lights, and the machine flying at a sensible, but more than adequate speed to maintain a stable vertical profile.
The absolute limit for an approach at night (MDH) is "Deck height +50 feet".
Here in lies the crux of the problem.
At the end of an ARA conducted in marginal conditions the crew, theoretically, have 50 feet of cloud free air in which to operate. This means that the point in space, where full visual references are available, ie "The fully formed rugby ball" is very very close to the helideck.
This means that to make a stable descent from this point the Groundspeed and therefore the airspeed has to be very low......OR the crew reaction, as seems to have been in this case, is to desperatly shed that speed, way to late, resulting in instability and loss of control and visual cues.
A SIMPLE BUT EFFECTIVE PROCEDURE
In my view....if we accept that the only point in space, where full visual flight can begin, is the "Rugby Ball", (Lets call this point "Calling the Ball" or CTB) the current regulations of "Helideck +50 feet" is way too low.
In my view, to gaurentee a stable final approach, this figure should be "Helideck + 200 feet" - and absolute minimum of 400 feet.
If, we accept this for a moment, we now have the makings of a sipmple, effective and safe procedure that would, if flown within parameters, ensure a stable final descent.
The piece of airspace underneath the MDH (Helideck + 200 feet or 400 feet), leading up to the CTB should not be available to the crew, ie no descent below that imaginary line drawn horizontally from MDH to the CTB should ever take place.
Finally we need to control the entry speeds for such a procedure. There are plenty of options but how about "Established at MDH, into wind @ 1.5Nm @Vy" as an absolute minimum.
Further reduction in KIAS, (to provide a sensible G/S) shall only be permitted in level flight at MDH, and to an absolute minimum of 50 KIAS at the CTB.
In summary, what I am proposing is to move the point in space where the rugby ball is fully developed, higher and further away, so that a stable airspeed can be maintained until the true transition to visual flight can take place..at the CTB.
Finally, and this is the most important point of all...INTERVENTION. By specifying this procedure and mandating the minima, both MDH and airspeeds at the Gate and CTB, the NHP now FOR THE VERY FIRST TIME will have a defintive intervention policy when the HP is not confroming to the profile, (ie descends below MDH before the CTB, or the airspeed drops below 50 kias between the Gate and the CTB).
USE OF AUTOMATICS OR OTHERWISE
For those aicraft fitted with couplers, the use of the coupler during this procedure should be mandatory (forget the argument for when it is broken the MEL says VFR only).
For those without couplers adherence to the profile and the intervention policy in provides the NHP puts them in a much better place than we all are right now.
What I have suggested above, before you rip into me, is safer, easier and simple.
It is not the full ARA procedure and would be suitable for shuttling. For the shuttle, for those fitted with it, the Alt Aquire prior to take off is set to the MDH for the next platform and once at that MDH, after take-off, the airspace beneath it, leading right up to the next CTB is not avaiable to the crew.
It may mean we do not fly some of the flights that we currently accept, but it will not be many and quite frankly we should welcome not having to push the to the current limits.
ANSWER THIS QUESTION
For those of you who still wish to fly a fully capable helicopter, manually, at night, during an offshore approach because you feel your skills might deteriote, I pose you the simple connudrum below:
FLIGHT ONE
Crew Operates the AC (IAW Double Bogies profile), making full use of the automatics. the NHP has a clearly defined intervention parameters and policy, and the crew follow the procedures, monitoring all parameters until the HP "Calls the Ball" whereupon they de-couple, gently reduce speed (couple of beeps back) lower the lever slightly and descend fully stable with a nice fat rugby ball to guide the HP to the deck.
If at any time the helicopter descends below MDH, or the speed drops below 50 KIAS, before the CTB, the new co-pilot (trained and breifed) knows exactly what to say, and in extermis what to do.
Up to the CTB, the crew rely on the £1m set of instruments displays and automatics to ensure that the helicopter follows the pre-designated profile, Both pilots effectively monitor the machine doing it work.
FLIGHT TWO
Crew, despite operating a fully capable helicopter, elect at 600 feet to de-couple and fly manually to the platform. The HP descends to 300 feet, the WX is marginal but the platform is vsiual and they begin to manouvre to try and find the helideck. The deck is 245 feet off the sea. They have to be within 200 metres of the deck before CTB is available. To get there, and still make a landing the airspeed has to be around 30 KIAS (Think of the LDP speed for a CAT helipad landing).
From the point they elected to de-couple, the crew and the pax they carry rely on the physical flying skills of the crew and the optical illusions that flying over the sea at night provide. The NHP has no intervention parameters (apart form his common sense) and there is no intervention policy in place.
Now........which of the above flights would like your Wife and Kids to be on.....
DB has not gone quiet....he was thinking.
P.S> All I have written above is fag packet stuff, intended to give food for thought,. I do not have a very large brain so any proposal like my suggestion needs careful consideration to ensure that Type specific issues are addressed, shuttling is not overly compromised and all the other bits and bobs like RADALT bug policys, resolving QFF over sea and so forth need overlaying.
However, at face value, it is unbelieveable that none of what I have described above exists today other than out own perosnal ideas and procedures that we have developed over the sea at night. Most of which being the result of giving ourselves a good scare.
I have over 8000 hours of offshore flight experience of which neary 1500 has been conducted at night. I have flown S61, L and L2 pumas. I am convinced that the development and adoptionsof procedures such as I have described above is the key to preventing incidents from happening like that poor BOND crew have suffered.
I am sure right now they are sat in their houses feeling really bad about what happened and maybe some guilt. In my veiw they are completely blameless as all that happened to them is the very last hole in the swiss cheese lined up, all the other cheese holes, (lack of procedures, non-mandated automatics, lack of intervention policy, MDH way too low, culture of manually flying) had already lined up!!!!!!!!
DB
Last edited by DOUBLE BOGEY; 28th Feb 2009 at 15:07.