On a normal day in office, the twin-engine workhorse of offshore industry – AW 139 helicopter – transitions to automation within seconds of takeoff. The crew have their roles cut out as ‘Pilot Flying (PF)’ and ‘Pilot Monitoring (PM). Switching between flight phases is mostly accomplished by rotating knobs and push buttons or selecting modes on the autopilot. Long sorties – often two hours or more – can feel like cruising on a highway as the machine chews up air miles at 140 knots. A few minutes before landing, PF returns to the controls when the ‘fly attentive’ phase commences and the sortie ends with ‘fly manually’.
It was not always this way. As a beginner, many of us built time on light singles like the R-44 Raven or Alouette. Helicopter pilots may wistfully recall their days of ‘hands-on’ flying that can test the patience of young pilots growing up today in an increasingly automated environment. Somewhere down the line, a few of us transitioned from ‘light singles’ to ‘medium twins’; some even to ‘heavy’. Twin-engine rating is earned after rigorous transition training in ground school, simulator, instrument rating and the check ride.
This story is a recapitulation of some lessons I learnt along the way. For those who are at the threshold of transitioning from single-engine to multi-engine, this may help focus your attention in the right places. Your flight instructor is best equipped guide you through the process. This is by no means a comprehensive or complete list. Every aircraft has peculiarities and nuances only a flight instructor can detail. However, there are common elements every transitioning pilot would do well to understand. So, here’s to building that list right.
Certainly an Upgrade!
If all missions could be undertaken by a single-engine helicopter, modern machines such as Leonardo’s AW 139, 169, 189 series, Airbus Helicopters’ H-145, H-160, Bell Flight’s 525 ‘Relentless’ or the Russian goliath Mi-26 may have never rolled out of a hangar. As the demand for better performance, payload and specialized missions evolved, manufacturers had little choice but to add another powerplant (or two). Each category of rotorcraft grew its own niche, filling crucial gaps, saving lives, creating value and generating revenue.
More Engines, More Systems
Contrary to popular perception, the distinction between the two main categories is hardly about the number of engines alone. With twin engines comes improved redundancy – not only in the number of engines but also in associated critical systems and subsystems. The Alouette I flew for many years had a single engine, one starter-generator, single servo for power-assisted controls, and no automation or integrated navigation system.
Compare this to a modern twin-engine cockpit where almost every system has a second, or even third standby built-in. Don’t let that bother you during the transition. As you complete your type rating, familiarity with these systems will improve; even more as you fly on the line. As you fly and gain experience on the line, your scan pattern and dexterity with handling multiple systems will get honed. Most systems are simply duplicated and complexity does not necessarily increase on a linear scale.
From Single Pilot to Multi-crew
Many single-engine helicopters are flown by a single pilot. This can breed secondary habit patterns because you usually fly ‘hands-on’, navigate, operate the radios, monitor systems, look out for weather and obstacles, handle abnormal situations and complete the mission, all by yourself. If you were lucky, some roles may have included another crew member or an aircraft maintenance engineer (AME) beside you. But, for the most part, light singles are designed and operated single-pilot. It keeps costs down and payload up.
As you transition to twins, one must get accustomed to the concept of a multi-crew cockpit. Tasks are shared here. Unlearn the habit of doing everything yourself. Understand the division of responsibilities between PF, PM and other crew members. A healthy cockpit should not leave any single crew member task-saturated. Cockpit work in a modern twin may involve long periods of relative calm interspersed with sudden spikes in activity as you execute complex missions or traverse controlled airspace with dense traffic. At all times, Crew Resource Management (CRM) must guide your actions so that spare capacity is available to deal with abnormal situations, should one arise.
Level of automation is another notable change between light singles and their heavier cousins. One of the most vital aspects of the transition is getting used to the idea of flying the aircraft through automation. Most modern machines are designed around the idea of automation. Automation alleviates crew fatigue, improves performance, allows for day/night, all-weather operations and enhances safety. The handling and optimum use of automation will be taught to you briefly during type rating. However, since type training is usually a packed syllabus, the lion’s share of learning to manage automation will come from flying on the line. Let go the old habit of grabbing controls all the time. Helicopters equipped with Automatic Flight Control Systems (AFCS) and flight directors employ long-term attitude retention modes where the controls are kept in place by trim switches and magnetic brakes. Deviations are monitored and corrected by autopilot actuators before they even become evident to the pilot. The old habit of keeping the hands tightly around controls may need to make way for ‘hands-off’, ‘fly attentive’ or, when the situation so demands, ‘fly manually’. The distinction and implications should be clearly understood for “managing the magenta” and avoid ‘fighting with George’.
Use of Checklists
Checklists are germane to all cockpits. However, a lone pilot at the controls of a light-single may not have the luxury of ‘challenge & response’ method of completing checklists. Rather, ‘read-do-verify’ or memory recall may be the norm, especially for the flight phase. Most multi-crew cockpits strictly adhere to the ‘challenge & response’ method of completing checklists. Avoid the temptation to jump up or down the checklist. Stay in phase with other crew members to avoid spectacular bloopers. Haven’t we all read about people who cooked million-dollar engines because they were either ahead or behind the checklist, or simply failed at challenge-response. Experience is no panacea for this malaise (in fact, ‘high flight time’ has often laid traps). Stay aware, stay alert and stick to the checklist.
Understand AEO & OEI Performance
As a single engine pilot, you had only one engine and its performance to be bothered about. Twin-engine helicopters come with more detailed performance, including Category A takeoff / landing profiles, All Engines Operative (AEO) and One Engine Inoperative (OEI) graphs and special procedures to exploit the enhanced performance obtained from twin engines. It is essential that these graphs, profiles and their limitations are assimilated. It may seem like a tall order at first, but good transition training syllabus will walk you through performance, both during ground school as well as flight training. In any case, no type rating is complete without achieving a safe level of understanding in interpreting and using the performance data given in the rotorcraft flight manual.
VFR When You Can, IFR When You Must
Most single-engine helicopters are designed to operate under visual flight rules (VFR), which implies ‘see and be seen; hear and be heard’. The first of fully-IFR certified light singles are just entering the market. It is thus likely that single-engine pilots are more familiar (and comfortable) operating in the VFR environment. Modern twin-engine helicopters come with full IFR certification and all the bells and whistles required to operate under IFR. Unless mandated for specific operations, it is a gross underutilization of such machines if they are still limited to ‘VFR-only’ operations.
The annual check-ride apart, make use of every opportunity to file and fly an IFR route, do the odd DME arc, and ride the VOR or ILS when you can. This, while exploiting the full capabilities of your modern helicopter, can come in handy some rainy day when you have to switch to IFR. Quite a number of single-engine pilots either don’t know or don’t care for VOR radials, flying the arc, or doing coupled approaches – mostly because they got by without this in the VFR environment. In the business of flying, it is never too late for old dogs to learn new tricks. Military pilots transitioning to civil aviation may particularly like to focus on this area. No more luxury of your own exclusive ‘military airspace’! A fully-equipped modern twin must navigate through IFR airspace with ease just like any airliner. This is unlikely to happen if you treat those smart boxes in the avionics rack with disdain.
Handling of abnormal procedures may follow different protocols in a multi-engine helicopter. Eschew the tendency to grab controls at the first signs of trouble. Except for rare events, twin-engine helicopters seldom have many ‘act immediately’ abnormal procedures. There are redundancies both in crew and aircraft systems. A well planned, rehearsed and agreed sequence of actions dictated by checklist usually follows any abnormal occurrence. Stick to it and you will be able to deal with any emergency. I am aware of at least one case where the pilot pulled the fire handles at the first sign of a warning light, without either confirming the action or reverting to single-engine flight. The hasty action shut down one engine while toasting the other – a situation that could have quickly spiraled out of control had they been in a critical stage of flight. Remember the old maxim: ‘aviate, navigate, communicate’. Now you are in a multi-crew cockpit. No grabbing of controls, pulling handles or switches without regard to that valuable resource sitting next to you.
Load & Trim
Weight and balance is another consideration that assumes importance while flying twins. This is not to say that they are any less important in light singles. The nature and design of larger helicopters means bigger cabins, more payload, longer missions and thus a centre of gravity (CG) that shifts as fuel is consumed. It is a regulatory requirement to calculate weight and balance for takeoff and landing in most countries. In any case, it is the right thing to do regardless of what and where you fly.
In helicopters, transition, whether from hover to level flight or from single-engine to multi-engine, could get a little rough. But that is just a phase beyond which lies the rich promise of becoming ‘multi-engine IFR Captain’ and all that comes with it.
Good luck with the transition and happy landings!
(A lightly edited version of this story was first published in VERTICAL Magazine’s Oct 2020 issue (page 88). You can access it here)
©KP Sanjeev Kumar, 2020. All rights reserved. I can be reached at firstname.lastname@example.org. Views are personal.
Disclaimer: If you are a flight crew, please consult and abide by national regulations, the Rotorcraft Flight Manual or Aircraft Flight Manual and your company’s Operations Manual as applicable to the type you fly.