Taking off from a Heliport
 

I'm only a lowly PPL(H) with low hours, so I'm just curious, and my apologies in advance if this is a stupid question! I was recently in Vancouver watching the helicopters arriving and departing from Downtown Vancouver Heliport. I thought I heard somewhere that when departing from a platform over water, it was usual practice to climb backwards before transitioning into forward flight, so that if the donkey quit, you had a chance of returning to base, but watching the operations, all aircraft lifted into the hover and then departed straight across the water. Just wondering if I mis-heard what I thought was common practice.

Hopefully I won't get shot down in flames for asking?!

Climbing backwards is usually done when operating multi-engine helicopters. It allows safe return if one engine fails before there is enough airspeed/altitude for continued single engine flight. The procedure and performance figures are in the RFM

Single engine you go swimming..

Thanks for this, but they looked like S76's which I thought were twin engined?

The climbing backwards departure you describe almost always means a lower take-off weight due to performance limitations, restricting the amount of fuel and/or pax that can be carried. Depending on local rules/regs, water landing may be an acceptable reject option in the event of a failure at a critical stage of flight (risking damage to the airframe if an engine quits at the wrong moment, but in theory not the pax and crew if the heli is equipped with emergency floats). This then enables the operator to use the clear area departure profile and utilise the full MTOW. Most (all?) S-76s have emergency pop-out floats within the wheel-wells

They are.
76s come in various models with different gross weights and power-plants of various HP.
This means that some, notably the 76 A, don’t have a huge surplus of power available in the event one donkey resigns. the 76A ++ , 76 B, 76 C++ and 76 D have a much better margin to play with in the event of mutiny in the engine room.
Various departure and landing profiles can be flown and the debate over which is safest is ongoing.
Factors such as wind, temp, gross weight, space and drop down height available for an abort or flyaway not to mention company SOP and TC regulation.

Best wishes in your future aviation endeavours.
Remember if in doubt …RFM and if that doesn’t work ask and listen. 90% of pilots will be happy to answer ( time permitting ) ….but take a grain of salt with the meal.
“Common Sense Should Prevail”:……Ask yourself ….”Would I do this with my dear mother aboard?”
Oh …..never forget the hover check and clearing turn before attempting aviation.

Would also depend on whether they are private or commercial aircraft. Commercial twin engine helicopters are required to do the backup take off, whereas private aircraft are not.

Not true. In simple terms commercial aircraft are required to fly the CAT A profiles as prescribed in the RFM.

Generally Airbus (and it's predecessors) have published a 'back-up' profile for ground level helipads, whereas Sikorsky favour a vertical profile. Elevated helipad operations, such as those found offshore, also use a vertical profile.

In this case, with president Macron on board, no CAT A departure, just a generous pushing forward (it did not seem power limited at all)
a case can be made:

• its quicker
• less time exposed as a static target (missile and drone attack...)
• aircraft with unquestionable maintenance (millitary)
• good weather visibility

To the OP
A more generalised explanation.

Many ME machines can be operated “performance class 1” The definition of this is that suffering a SE failure: a crash can be avoided. Either by landing, or flying away.
To ensure this performance: weights/profiles/techniques described in the RFM must be followed exactly.
It’s largely up to the operator/operation as to whether the machine is operated to these standards. As mentioned the weight might have to be reduced. Often significantly. Potentially some machines couldn’t operate PC1 from some locations at any weight.

An analogy with your assumed SE experience. HV curves. From a clear area, you could follow the graphs in your RFM, and be capable of an auto rotational landing from any position in your departure. From a confined area, your only option might be a vertical departure that puts you in the HV “avoid” area. An engine failure in the avoid area will likely result in a crash (safe landing not demonstrated during certification testing). A risk most SE pilots accept, but minimise. The risks are often dictated by the local rules dependent on operation.

Hope this helps

Not true: they can operate PC1 or PC2. If PC2 they need to be able to conduct a safe forced landing in the event of an engine failure before DPATO. I assume they have floats and consider a ditching to qualify.

well, SE can climb backwards as well :ok:

Thanks for all the replies. The flights were definitely commercial as they run shuttles from Vancouver to Vancouver island.

You’ve been watching Dave Fishwick YT videos!

To answer your question, they fly in performance class 2 (PC2)...so yes they can take off over the water...as explained by previous posts...

Great view from the Fairmont Waterfront of those busy S-76s going "oat and a boat" their business. Also the stacks of floatplanes, the cruise ships, and trains all with Vancouver Harbour as their hub. Busy spot.

The backwards takeoff is controversial, if only because you are going backwards downwind in the early stages which is why it shouldn't be done in single-engined helicopters because when the engine stops you will go down vertically and not get back into the departure point.

The other thing about it is that it should be done dynamically, which is what keeps you out of the H/V curve. This means it shouldn't be done too slowly - the 76 I believe requires a rate of climb of 1000 fpm, so if an engine quits you have momentum behind you. The other reason for not hanging about concerns the tail rotor - you will have full power pedal at the top of the climb, which is a very vulnerable position to be in. If the tail rotor goes you are stuffed. The truth is that people are so twitched up about engine failure they forget the rest of the machine.

I holidayed at Jolly Harbour in Antigua and noted that at the heliport there (which used 2 x Longrangers), they air taxied backwards for about 50 yards before lifting forwards.

Actually, not strictly accurate. The TR went to maximum pitch - I think maybe more than full power pedal input - so reducing the power to get down created an uncontrollable yaw. The final straw was landing on a small wall, with the gear up, which ruptured the belly and tanks.
​​​​​​​https://www.gov.uk/government/news/a...7-october-2018

To make that clear, that aircraft’s tail rotor blades ran from a high power pedal situation, beyond neutral and to full negative pitch. Just about the worst situation any helicopter pilot could ever experience - it is worse than a tail rotor drive failure and almost certainly irrecoverable.

Thanks for the correction - I had forgotten that.

On the other Hand, the chances of a TR failure are much smaller (like a thousandfold) than an engine failure. So no reason NOT to Backup. The guys in Leicester were simply extremely unlucky. The Dynamic rearward Part depends on the helicopter type. Same for the „fly-away“ Profile. On a H145 it is all very easy and slow as the bird has plenty of power. In a 109 you have to nose it over aggressively to fly away without too much altitude loss.