It was late evening on my sixth consecutive day of offshore flying duty. I had flown close to 24 hours over the last six days — well within the regulatory flight time limit of 30 hours over 7 consecutive days. I was planned for a routine called ‘drying run’ – ground running all helicopters on the line after the daily engine wash. The next day was to be my weekly day off as per company rules.

Qualified and current on two types, viz. the Bell 412 and AW139, I was among few pilots in the company who could be planned to fly either type, dictated by crew situation and flying program. In many countries, this is permitted by rules subject to meeting basic qualifying time on both helicopters, currency and recency requirements. There is an overriding rule of ‘one type per day’ that applies to all dual-rated pilots in India.

Military to Civil Aviation Transition

In the military, transitioning from light, single-engine helicopters to twin/multi-engines with specialized roles and complex missions was seen as career progression. If you performed well, further courses like Flight Instructors Course, Helicopter Combat Leader (HCL) or the Experimental Flight Test Course (FTC) await.

I had done my time, hung my military overalls and was now a full-time, dual-rated offshore pilot: Captain on Bell 412 and First Officer on AW139. Helicopter operators flying for the Oil and Gas (O&G) industry find it convenient to keep crew qualified on more than one type. For the company, it gives greater latitude in crew deployment, provides upgrades to aspiring crew and allows smooth transition during a fleet churn. However, the operating environment, ethos, safety paradigms and regulatory framework differ from country to country. It is certainly different from a military setup.

The Unseen Hand of Fatigue

A commercial flying licence is the pilot’s singular responsibility and must be safeguarded from regulatory minefields. When the guard is down and silent hand of fatigue plays tricks on your mind, strange things can happen, as it did with me that evening during the drying runs. After six days of flying, mostly on the Bell 412, I had completed four hours of flying that day on the AW139. I had not rested much after the sorties and still had another hour or so of ground runs to complete. I was also reaching the back end of my 6-weeks duty roster. I was looking forward to the break – still five days away – to get over the accumulated fatigue.

Differences in Cockpit Layout

As two helicopters serving the offshore industry, the Bell 412 and AW139 are different as chalk and cheese. The 412 has a conventional ‘steam gauge’ cockpit with twist-grip throttles. The AW139 has a ‘full glass cockpit’ with Flight Management System (FMS), Electronic Engine Control, and all bells and whistles that adorn a modern rotorcraft. Engine start on the Bell 412 EP is almost entirely manual where the pilot has to open throttles and pour fuel into the engine. The AW139 has a fully automated start using a 3-position engine mode switch. The second engine start on 412 is generator-assisted while it is standard procedure to start both engines of AW139 with a ground power unit (GPU). The Bell 412 has skid landing gear while the AW139 has retractable undercarriage. There are subtle differences a dual-rated, cross-flying pilot has to be mindful every single day.

While the fundamentals of starting a turboshaft engine remain the same, the presentation of engine instrumentation, manual interventions and nuances of both these helicopters can lend themselves to habit interference if the mind is not 100% alert. I met both these criteria that day.

Attention Shifts, Habit Interference Takes Over

I started to crank the second AW139 on the line that evening. It was a smooth start and the first engine settled down at idle. I should have signaled the ground crew to move over to the other engine. Instead, I found myself waving off the external supply like I would on a Bell 412 after the first engine start (second engine start on Bell 412 is generator-assisted).

Two things went wrong soon after I had made the first mistake of disconnecting external power supply. The ground crew – apparently reeling under their own fatigue and low arousal issues – diligently followed my signal without question and disconnected the GPU from aircraft. They followed their post-start drill, I followed mine; interrupted by a seemingly minor deviation no one noticed. The second engine was not started and here I was, trying to get both generators on line – the next checklist item! Since the GPU was gone and number two engine was not started yet, how would that generator come online?!

The tarmac was busy that evening with other rotors started up. In the high ambient noise level, the small slip went unnoticed, even by ground crew attending to my aircraft. I summoned the engineer who joined me in staring at a generator that just wouldn’t come on line!

The Eureka (or Facepalm) Moment!

A few seconds of confusion later, I noticed that the second engine was not even started! Due to a momentary lapse of attention coupled with habit interference, I had broken the AW139 checklist, drifted into the post-start actions of Bell 412 and quickly returned to the AW139 checklist.

Two souls in the aircraft (pilot and engineer) had their facepalm moment for the day!

Rest of the evening was uneventful. We debriefed and owned up our slips. It was just a minor deviation. No broken parts, no damage; just a small bruise on the ego, and acceptance that while dealing concurrently with different aircraft types — potentially fatigued or during periods of low arousal (circadian rhythm) — mind can play tricks. If ever you find yourself in that space, raise your hand and call it a day! That could be the best decision you took.

So here is my list for those of you who routinely jump cockpits (essentially fixed or rotary; not both concurrently):

Adherence to Checklists

Be aware that playing within regulations doesn’t necessarily guarantee safety or immunity from all eventualities. Rules evolve with each accident or incident. Even if you are within the cross-flying criteria, keep your guard always up. One of the most basic safety mechanism is adherence to checklists. Rote memory is always susceptible in weak moments or during an abnormal situation. You could be well within fatigue limits and still reel under incipient effects of fatigue. So, if you are not feeling completely alert – stop and revive. Call it off if you still have that choice. There is always another day.

Rehearse Key Actions

Depending on the type you are planned for the day, revisit and rehearse key memory items that have to be performed without recourse to checklist or Quick Reference Handbook (QRH). There cannot be more than 2-3 events that call for immediate action. Ask yourself: Am I 100% sure about these memory items for the type I am flying today? My weak moment came when I did not have a captain or co-pilot sitting beside me. Turboshaft engines start quickly and there’s hardly the time to refer a checklist as the engine spools up. Noise and other stimuli in the environment can also distract. When in doubt, take a moment, pull out the checklist and analyze what is really going on. Remember that some situations can quickly go from bad to worse — either due overreaction or doing too little too late.

Identify Areas of Conflict

For the types that you fly concurrently, it may be a good idea to identify potential areas of conflict and remind yourself periodically to be extra alert while operating in those zones. For example, the fuel panel of Bell 412 and AW139 have certain design and locational similarities that can create a trap. The fuel valve of AW139 sits approximately in the same position on fuel panel as the Governor AUTO-MANUAL switch does on the Bell 412 EP. For a crew flying both types, operating the AUTO-MAN governor switch of Bell 412 instead of the fuel shut-off valve, in an emergency, could pose a real danger unless crew actions are cautious, deliberate and confirmed through challenge and response.

Twist grip throttles can also ‘roll-out’ a challenge sometimes. All the Russian helicopters I have flown came with twist-grip throttles that rotate inwards (towards the pilot) to open. The Bell series have throttles that rotate outwards to open. If cross-flying between two such cockpits (certainly an avoidable combination), be aware of the real risks of winding down a throttle when the desired outcome is just the opposite. If there is potential for a slip-up, chances are, it has already happened or will soon happen. Devise your own protection strategy if you must, including spending a few minutes of ‘chair flying’ when required. Sortie preparation is not meant only for ab-initio trainees. Some of the most spectacular bloopers have been committed by very experienced pilots.

Flying by Feel versus Flying Mechanically

The direction of main rotor (MR) rotation decides many things on a helicopter. If you are lucky to fly two types with the same rotation, good for you. Torque reaction and counter-torque pedal inputs needed to fly balanced comes from instinct for some, through practice for others. Any premeditated drill-type inputs can set you up for trouble when flying two types with contrary MR rotation. Some experts hold that real pilots fly by feel and ‘wear’ the aircraft, not ‘strap-in’. Surely a lofty ideal, but low time pilots can fall through this crack while jumping cockpits. Regulations in some parts of the world allow pilots with as little as 50 hours on each type to cross-fly.

In the navy where I flew over 22 types – sometimes three types in a day during my experimental test pilot career – it was a healthy practice to identify similar ‘type/mark/series’ or ‘origins’ (Western / Eastern) of aircraft to cross-fly. One of them would usually be a basic model (like the Alouette) and the other a light twin or heavier (like the Seaking MK42B or Kamov-28). ‘Only one type a day’ was the dictum followed in all operational units. Test pilots were allowed a dispensation, that too only when actively engaged in flight test duties. Then again, one of the crew members would be a ‘frequent flyer’ on the type. It is perhaps not a great mix to have two pilots, both cross-flying on a type they don’t usually fly. Planners should keep this reminder pinned on their board while drawing up the next day’s program.

Airline Scheduled Ops versus Helicopter Non-scheduled Ops

Lastly, helicopter operators may like to ponder why such cross-flying is not adopted by civil airliners or scheduled operators. Is it the high cost associated with keeping crew current & proficient on two types? Is it safety concerns arising out of habit interference? Would airline crew be comfortable rostering alternately on two types — say, a Bombardier Q400 and Boeing 737? Do regulations permit this? Should the same flight and duty time limitations that apply to pilots who fly single type be read-across for those who cross-fly on a routine basis?

As you put your mind to these questions, here’s a gentle reminder. A pilot is the last line of defence in any regulatory framework or safety paradigm. The best safety device in the world still occupies a small space between your ears. It’s not necessarily ‘safe’ because it is ‘allowed’ by rules. Always keep your guard up. Cross-flying when done with adequate checks and balances can be a win-win situation for both the company and individual.

Happy landings!

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(A lightly edited version of this story was first published in VERTICAL Magazine’s Nov 2020 issue. You can access that here.)

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©KP Sanjeev Kumar, 2020. All rights reserved. I can be reached at kipsake1@gmail.com or on my Twitter handle @realkaypius. Views are personal.

Disclaimer: If you are a flight crew, please consult national regulations, the Rotorcraft Flight Manual or Aircraft Flight Manual and your company’s Operations Manual as applicable to the type you fly.