Can a twin engine helicopter be ferried on one engine ?
Captain Eacott....Sir.....your yarn proves several things for sure.
The most apparent is there is Legality and there is Reality....and Forgiveness is much easier to obtain than Permission which applied to the Reality thing only gets in the way of accomplishing business.
Helicopters know naught of paperwork.
While working for Bristow I wore my Cowboy Boots as I felt they were appropriate footwear for the manner in which we operated at times.
Now back to Lamp Swinging....
I have flown many single engine flights in the Chinook A and B models.....both of which required some careful calculations to do so if starting from the ground and making a single engine takeoff.
It would have been the same for a C- model.....but the full C Model...just as in the Wessex (the twin Gnome engine version)....single engine performance was more than adequate.
We did try to have an escort for those flights in the event we were to experience a failure of the remaining engine as we were in a very inhospitable locale that more often than not was the reason for the first engine failure.
The Chinook was a pleasure to fly....and one of its characteristics was there was an airspeed that granted the best rate of climb.....and memory serves that it was 59 KTS IAS. (A Model)
A knot less.....and you went down.....a knot above....you went down.....and the key to an uneventful single engine takeoff and landing was to assess what indicated airspeed on that particular aircraft granted you the. best rate of climb and then maintain that airspeed until you were at a safe height above ground. As you burned fuel you could accelerate as you would have an increasing amount of power.
One afternoon at a place called Quang Nhai....in a B Model....I was given a demonstration of why all of the above was important.. It was a lesson that stayed with me.
I was a new Co-Pilot...new to the Chinook..new to the Unit...new to B Model....and new to flying combat missions....and upon my second session of being on a two way machine gun firing range....we had reason to land and assess damage to the aircraft to include determining why one engine was no longer running.
Decision was made to fly the machine home on a single engine....we burned off fuel to our planned minimum fuel quantity....lined up....did a hover power check and determined we did not have hover power....but were somewhat close to it.
We trundled off down the runway....at a somewhat disappointing acceleration rate (barely perceptible) but it was a longish runway......and when there was no more runway in front of us we were off in a cloud of dust with all of Quang Nhai City in. front of us.
We did great util about a hundred feet up....when the Aircraft Commander who was flying ....allowed the airspeed to decrease a few knots when we experience our first droop in Rotor RPM....at which point we were no longer climbing and in fact were losing some height.
My recollection of that moment Is triggered today whenever I see an old fashioned TV Antenna sticking up over a house....as I remember thinking that I had never seen so many of them as I did that day...looking out over the City.
We probably blew off some tin roofs and I know we hit several Antennas before getting to the countryside on the far side of Quang Nhai.
I never quite trusted that fellow after that even when we became House Mates back at Fort Rucker and wound up as Flight Instructors together teaching at the Chinook Conversion Course.
One of the Rules for the Helicopter Flight Of I adopted was....if it will not hover...do not fly it.
The most apparent is there is Legality and there is Reality....and Forgiveness is much easier to obtain than Permission which applied to the Reality thing only gets in the way of accomplishing business.
Helicopters know naught of paperwork.
While working for Bristow I wore my Cowboy Boots as I felt they were appropriate footwear for the manner in which we operated at times.
Now back to Lamp Swinging....
I have flown many single engine flights in the Chinook A and B models.....both of which required some careful calculations to do so if starting from the ground and making a single engine takeoff.
It would have been the same for a C- model.....but the full C Model...just as in the Wessex (the twin Gnome engine version)....single engine performance was more than adequate.
We did try to have an escort for those flights in the event we were to experience a failure of the remaining engine as we were in a very inhospitable locale that more often than not was the reason for the first engine failure.
The Chinook was a pleasure to fly....and one of its characteristics was there was an airspeed that granted the best rate of climb.....and memory serves that it was 59 KTS IAS. (A Model)
A knot less.....and you went down.....a knot above....you went down.....and the key to an uneventful single engine takeoff and landing was to assess what indicated airspeed on that particular aircraft granted you the. best rate of climb and then maintain that airspeed until you were at a safe height above ground. As you burned fuel you could accelerate as you would have an increasing amount of power.
One afternoon at a place called Quang Nhai....in a B Model....I was given a demonstration of why all of the above was important.. It was a lesson that stayed with me.
I was a new Co-Pilot...new to the Chinook..new to the Unit...new to B Model....and new to flying combat missions....and upon my second session of being on a two way machine gun firing range....we had reason to land and assess damage to the aircraft to include determining why one engine was no longer running.
Decision was made to fly the machine home on a single engine....we burned off fuel to our planned minimum fuel quantity....lined up....did a hover power check and determined we did not have hover power....but were somewhat close to it.
We trundled off down the runway....at a somewhat disappointing acceleration rate (barely perceptible) but it was a longish runway......and when there was no more runway in front of us we were off in a cloud of dust with all of Quang Nhai City in. front of us.
We did great util about a hundred feet up....when the Aircraft Commander who was flying ....allowed the airspeed to decrease a few knots when we experience our first droop in Rotor RPM....at which point we were no longer climbing and in fact were losing some height.
My recollection of that moment Is triggered today whenever I see an old fashioned TV Antenna sticking up over a house....as I remember thinking that I had never seen so many of them as I did that day...looking out over the City.
We probably blew off some tin roofs and I know we hit several Antennas before getting to the countryside on the far side of Quang Nhai.
I never quite trusted that fellow after that even when we became House Mates back at Fort Rucker and wound up as Flight Instructors together teaching at the Chinook Conversion Course.
One of the Rules for the Helicopter Flight Of I adopted was....if it will not hover...do not fly it.
Join Date: Oct 2009
Location: West Sussex
Age: 84
Posts: 148
Likes: 0
Received 0 Likes
on
0 Posts
Bristow Wessex used to ferry flight on one engine, and I had a conversation with Pip Smith (RIP) who did this a lot. He stated that he would leave the switches in position for a quick restart and would restart on approach to landing. The problem is that you could lose all the engine oil in the inoperative engine, each engine is different but on the Gnome, an inoperative engine will windmill at about 5% N1. This will be sufficient to generate oil pressure, but not enough to pressurise the bearing labyrinth seals, so all the engine oil could be lost.
Bristow Wessex used to ferry flight on one engine
Not my story, but passed on as legend on my first Puma Squadron was the Flight Commander who managed to get a fairly heavy Puma into the single-engine hover one night at Bessbrook, when he was half-asleep. I gather he woke up fairly shortly afterwards and landed back on to get No2 up and running! Having woken up at 2000' and about 0400 somewhere over South Armagh, wondering where the hell I was and how I had got there, I can empathise with his alleged mistake...
In Oz I'm told the twin Wessex used to fly enroute to the rig single engine as a fuel saving measure, a drop of some 25% in consumption I think the story went, the saved fuel being needed to cover required contingencies, flight had to be made at an altitude whereby a restart of the shut down engine could be made in the event of a failure of the one on line. I'm sure John could provide first hand info.
However, for many, many years we were able to plan AOS as an alternate when the forecast precluded an alternate some million miles away (1979 in the far NW of WA, flying to exploration fields somewhere off East Timor).
Until someone asked the question "where is AOS?" and was given the answer 'Any Open Space'
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,576
Received 425 Likes
on
224 Posts
I once had a problem with an engine oil hot warning (caused by an oil cooler thermostat failure). After discussion with the maintenance organisation it asked if it was possible to run the engine long enough to get airborne on two. It was and then the affected one was shut down for ferrying to maintenance. Starting it up again for landing caused no problems. No big deal but a bit cheeky I suppose.
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,576
Received 425 Likes
on
224 Posts
Relying on 40 year old memory here, but "yes it can" has to be balanced with "must you" and "should you".
If you look at the performance charts, you could lighten up an SH-2F (with the two T-58-GE-8F engines) sufficiently that one could, if the ship captain put enough speed on, hover single engine over the deck and then fly off to a 'feet dry' location (ostensibly to get a new engine put in and do the maintenance test flights ashore, etc).
However, one may also crane/lift an H-2 from the deck of a frigate. (And have it towed or put on a flat bed truck to a maintenance facility, yes, we once did that).
The Officer in Charge of that detachment (not mine) had proposed doing it, and was told not to, and the fact that he asked (as I understand how things panned out) took a hard bite out of a otherwise successful and promising career.
If you look at the performance charts, you could lighten up an SH-2F (with the two T-58-GE-8F engines) sufficiently that one could, if the ship captain put enough speed on, hover single engine over the deck and then fly off to a 'feet dry' location (ostensibly to get a new engine put in and do the maintenance test flights ashore, etc).
However, one may also crane/lift an H-2 from the deck of a frigate. (And have it towed or put on a flat bed truck to a maintenance facility, yes, we once did that).
The Officer in Charge of that detachment (not mine) had proposed doing it, and was told not to, and the fact that he asked (as I understand how things panned out) took a hard bite out of a otherwise successful and promising career.
Even light, that would have required an interesting take-off technique
Iran 1972
CH-53D with minesweeping kit. Demo in Iran completed, and weather on northbound egress was forecast light rain, which had morphed into very wet snow. The 53 guys had left us in the 67 some 100 miles south, as we did not even have inlet de-ice and the snow was piling up on our inlets. The 53 continued north, but eventually both of the EAPS ( engine air particle separator ) caution capsules illuminated. Pilots did not trust the Emergency Procedure ( which had arisen from a US Gov't agency test program, conducted by same ), so they opened only one emergency door first. Good Move! as that load of wet snow fodded the T-64 to the accompaniment of mush loud and harsh noises etc. This valley was at 6000' Hp. 53 guys hired a truck ad hoc to offload the 53 to the extent possible, got some help from the truck drivers etc to stop the traffic. Watched this from the 67 as we had been stopped 100 miles south of here, have NO inlet ice protection at all, and when the snow built up on the inlets, we landed in a mud hut village and were guarded by a spooky looking man with an 1800 vintage rusty rifle and no english. Three hours later,the snow had pretty much stopped, so we cranked up the 67 ( with an eye toward our "protector " ), and proceeded north until running into the 53 parked at the roadside truck stop.
