Aircrew Fatigue – An Indian Helicopter Pilot’s Perspective

Indian Case Study

Case 1: On 19th Apr 2011, a Mi-172 operated by an Indian carrier crashed short of a mountain helipad with loss of 19 lives. Minutes prior turning on to final approach, the captain had expressed a desire to sleep after the sortie, apparently tired of unscheduled night halts and changes in program. The copilot agreed that all of them could use some sleep, while the flight engineer added his lament about washing some clothes. This is typical helicopter crews’ life. The Indian Air Accident Investigation Board (AAIB) chose to rule out fatigue as even a contributory factor, possibly blindsided by the other glaring errors of omission & commission (read the report here).

Mi-172 Crash at Tawang 19 Apr 2011 (Pic from AIB Report)

Case 2: Exactly eleven days later on 30th Apr 2011, another helicopter crashed in the hills after taking off from the very same location – Tawang. The ill-fated AS350-B3 had taken off from Guwahati to Tawang to meet an airlift requirement for the Chief Minister of Arunachal Pradesh. The AAIB observed that ‘the pilots were in a hurry’, missed some mandatory R/T calls and flew a positioning flight of approximately 0:50 minutes with ‘poor flight planning’ prior landing at Tawang. After the positioning flight, they switched off, refuelled, started up again, and repositioned on the same helipad to embark the Chief Minister and his team – all within 0:14 minutes with no help from any dispatcher or handler. On initial liftoff, the helicopter yawed 70º-80º due overloading. It took the crew three attempts, each time offloading some pax or cargo, before they could finally get airborne.

Minutes later, they smashed into a hillside killing all on board. The duress under which the crew must have operated that flight can be understood if not condoned.  Attributes of poor flight planning, violation of SOP, flying indiscipline, etc were heaped on the deceased pilots (both ex-Indian Army) by the AAIB. But no fatigue analysis of the crew was done (read the report here)

VT-PHT Crash at Tawang 30 Apr 2011 (Pic from AIB Report)

American Case Study

Dr. Katherine A. Wilson, a Senior Human Performance Investigator with the NTSB, presented two case studies to highlight the ‘nuts & bolts’ of fatigue investigation undertaken by NTSB in a research paper (read that here).

Case 1: In the first case, an Airbus A300, UPS Flight 1354 crash of 14th Aug 2013, investigators obtained crew data through interviews, company records, hotel records, cellphone records, and information from six personal electronic devices found in the crew members’ personal possessions to determine the contribution of crew fatigue in the accident that killed both pilots. As per the NTSB report ‘less than 90 min before going on duty, the first officer texted a friend stating, “I’m getting sooo tired.” About 2 hours later, she sent another text stating, “hey, ba[c]k in the…office, and I’m sleepy….”. The NTSB’s report (read here) is an eye-opener for those interested in drilling below what’s purely obvious.

UPS Flt 1354 Crash (Pic courtesy NTSB Report)

Case 2: In the second case, an AS350-B2 helicopter operated by Sundance Helicopters crashed 7th Dec 2011 near Las Vegas while on a sightseeing trip, fatally injuring all onboard. The NTSB report (read here) cited a mechanic and inspector’s fatigue due circadian factors and sleep debt as contributing to an improper (or lack of) installation of a split pin that brought down the helicopter. Both were working a shift system but were pulled out on their off day to work on the aircraft. Sounds familiar?

Sundance Helicopters AS350 Crash at Las Vegas (Pic from NTSB Report)

Helicopters are Different!

With due respect to Harry Reasoner, allow me to tweak his famous quote. My version reads as follows:

The helicopter pilot is maintained in the air by a variety of forces and controls working in opposition to each other to provide work & rest. If there is any disturbance in this delicate balance, the helicopter pilot does not stop flying immediately and disastrously, but gets tired, sleepy & distracted. There’s no saying what will happen next“.

Harry Reasoner’s gloomy outlook doesn’t seem to have seeped into the rule making process for Flight Duty Time & Flight Time Limits (FDTL) for helicopter crew. Read the current Indian FDTL limits for aeroplanes here, and the one for helicopters here. The limits are comparable, the service conditions are not. You wont find any relief turning to FAA or EASA. Their limits are even more lenient and generous, keeping with their scale of operation and powerful lobbies that influence every legislation.

The Civil Aviation Requirements (CAR) for helicopter FDTL in India has been in force for 18 long years. Meanwhile, much has changed. Indian skies opened up, LCCs came in, now everyone can fly. Growth of helicopters has been sluggish owing to many issues, some of which I had covered in an earlier story. There have been sporadic attempts at revising the helicopter FDTL by DGCA; none successful. An uneasy status quo prevails.

Aviation is a costly business and there’s much more to it than physics or aerodynamics. As we scale up, there’s bound to be temptation for scope-creep in FDTL. This article aims to offer a sobering perspective to those who may be sympathetic to this cause.

How is Helicopter FDTL Arrived At?

Frankly, I don’t know. Perhaps, we discuss and debate airline-oriented FDTL based on circadian rhythm, red-eye flights, time zones etc, then ‘eyeball’ some revisions to rationalise it for helicopter crew, throw in a clause or two for special operations, and then frame rules for helicopters. When an accident or incident takes place, fatigue is hardly ever accepted as a contributing factor. Effects of fatigue usually manifest in incorrect or inappropriate actions that are easy to pin on the crew, especially if they are no longer around to defend themselves.

Business Interests & Regulatory Frameworks

Helicopter operators – especially those in countries like India who are struggling to stay afloat against a rising tide of regulations and compliances – are hardly prone to suggest downward revisions to FDTL. It’s counter intuitive and akin to kicking one’s own ass.

In the US, HEMS is one of the most accident prone segments of the industry. As per one study quoted in AINOnline, in 1980, a HEMS crew member had a 1 in 50 chance of being in a fatal accident. In 2016, that number stood at 1:850. The industry saw many upheavals in between. But even at the nadir of EMS’s bloody history, no major revision of flight time & rest requirements was sought, not even for single-pilot ops. Even today, they continue to operate under the same CFR Part 135 rules as applicable to commuter and ‘on-demand’ operations. Every aspect, including red tape, new technology, just culture, collaborative rule-making, etc. has been discussed. The FDTL rules still stands unmoved like the Rock of Gibraltar.

Sandwiched Between Rules!

Borrowing some cheese from James Reason’s Swiss Cheese Model of accident causation, I have prepared a McFatigue sandwich for better understanding of this subject. ‘Mc’ stands for ‘machine computed’ and means no offence to the famous line of American burgers.

So long as people fly for a living, there’ll be fatigue. Flying for many like me is daily bread, the regulator and operator forming the bread in the sandwich, with many ‘fillings’ that come with the meal. Without bread, there can be no sandwich and we all respect that.

However, some recipes work, some don’t work that well. Some are recipes for disaster. The trick lies in identifying the fillings and knowing when to stop stuffing your McFatigue sandwich.

Sadly, FDTL today has been reduced to a number crunching exercise on MS Excel or some other ERP. The drawback of such a system is that you could be well within your FDTL and still be reeling under fatigue. Or you could exceed your FDTL and still feel perfectly fine. There is accountability but very little humanity in it.

Is Airline Fatigue = Helicopter Fatigue?

Most research about what causes fatigue is fixed-wing centric. In fact, if you google ‘what causes fatigue among aircrew?’, you may not find a single, leading study on this subject from the helicopter pilot’s perspective. In India, The Nasim Zaidi Committee Report of 2010 on FDTL and Rest Requirements for Flight Crew Members (arguably a comprehensive analysis of the subject) left out helicopter pilots, clubbing them with cabin crew as the subject of a separate study (I couldn’t locate that report). Sure enough, the distinction between fatigue in airline (scheduled) operations and helicopter (non-scheduled) operations is hardly evident in the rules as of end-2018.

What’s a Good Day?

On an ideal day, a helicopter pilot would turn up in office, perform the ‘on-camera’ regulatory blow-job on an Alco-sensor Mk IV (in India, we measure what’s easy to measure; fatigue isn’t one of them), complete preflight preparations, walk to the aircraft, board passengers, start the engines, obtain takeoff clearance, undertake a sortie or two, and return home or to allotted quarters.

Most FDTL rules are adequate to cover this fairy tale. Now let’s start adding fillers and sauces to the sandwich.

Effect of Delays

Unlike other countries, helicopters are a perennial nuisance for air traffic managers in India. Delays are endemic to this industry, all of which operate under an NSOP, private charter or with state governments. Starting from flight plan clearances, every activity to get airborne from or land at any respectable airport gives you the feeling of being just that – a nuisance. You are the poor cousin who grew up on the farm. Ask any helicopter pilot how many times he has ‘watered’ the bushes around the tarmac; or when he or she last had access to clean lounges or Starbucks.

As you burn up fuel and body fluids in non-air conditioned aircraft, fatigue creeps up on you. Your saviour is 10 hours of flight duty time (extendable to 12h), including 7 hrs of flight time. it’s not unusual to get launched for a sortie in the 8th hour of your duty and undertake 10 landings before you sign off for the day. The first filler in your McFatigue sandwich is here.

Effect of Extreme Climatic Conditions

There was a time in India when only the rich could afford cars. Now even the middle class can afford them and they all come with air conditioners (AC) or exotic climate control systems. In an equitable comparison, today you’ll find more non-AC helicopters in India than non-AC cars. During summers, temperatures can soar upwards of 40 degrees with high relative humidity in large parts of India. The mountains of north / north-eastern India which are serviced by single-engine, single-pilot helicopters freeze-over during winters. Add raincoats, accessories and a maevest to your wardrobe. Jackets that keep you from freezing atop mountain helipads turn into heaters as you descend into the plains. Do the rules account for this? Please add this filler and get your new sandwich.

Effect of Noise & Vibration

Helicopters are extremely noisy and vibrate like hell. They radiate noise outwards and inwards. Not all pilots fly VIPs with bespoke interiors or noise & vibration attenuation equipment. Neither are active noise-cancelling headsets an industry standard. If you are operating from a busy heliport like Juhu, the scream of multiple helicopters cutting through your entry-level aviation headset, vibrations of your 80’s-model eggbeater, and constant RT natter (compounded by micro-managing controllers & pilots who love their voices) can wear you down even before you liftoff. Your McFatigue has another filler.

Effect of Weather & Terrain

Helicopters operate within a narrow band of a few thousand feet from the ground. This is the zone most prone to dangerous encounters between rotors, weather and terrain. In India of late 2018, almost all helicopter operations are still ‘Day-VFR‘ only.

Monsoon or inclement weather brings with it a multitude of challenges. There are no aerobridges or air conditioned Volvo buses to cart you to the aircraft. It’s not unusual to find crew and pax wade through ankle-deep water patches, shielding themselves from the rain with naked palms to reach their helicopter or terminal (if you are lucky to operate from one).

Weather also forces helicopters under NSOP to rely on ‘Special VFR’ clearance for arrival & departure. In India, this could mean departure and arrival sequencing with 10-minute intervals. If you are 4th in arrival sequence, that’s a 40-minute delay. Since VFR requires no mandatory diversions, everyone is flying on marginal fuel in the tanks. Without any current regulation here that mandates PBN, TCAS, EGPWS or ADS-B, the temptation for cutting corners or getting one-up on a fellow flier is high. Also, you will most likely be scud-running to avoid getting snared by the ‘VFR into IMC’ trap.

There, pour this sauce over the toppings you already have on your McFatigue sandwich.

Effect of Off-Base Layovers

My airline colleagues use a fancy term called ‘layovers’ to describe what offshore pilots know as ‘night halt’ or ‘enforced halts’. The difference couldn’t be starker. Offshore platforms are not exactly Radisson Blu or Hilton hotels with sophisticated sleep systems. It’s not designed to be that way. We share cabins and washrooms, sleep on bunks, suffer our roommate’s snoring & farts, carry our bags up steep, metal staircases running 6-7 stories high to get to our room or the helipad. It’s noisy with risks of fall-injury, hot gases, H2S exposure, galley food, and vermin. Yes, folks out there do what they can to ensure aircrew comfort, but it’s neither home nor a star-hotel. Good sleep under such conditions? When you return from night halt, most people want to run back to their homes and spouses (where incidentally more ‘duty’ awaits! Read it here).

Helicopters and the night sea

Add this slice of cheese to your McFatigue.

Effect of Rostering Systems

Some industries like offshore O&G and EMS work to an ON-OFF roster system to address the issue of ‘accumulated fatigue’. For touring pilots, this means long periods away from home and their loved ones. While some may cheekily argue that there is more work at home than in office, the effect of long periods away from home cannot be taken lightly. I remember receiving that horrible call no touring pilot ever wants to hear: a family member being rushed to hospital just as I was getting ready for a flight. Fortunately, I had a boss who asked me to drop everything and fly home. Not everyone is lucky to have such an employer.

Outstation crew fight a daily battle balancing familial and aerial challenges. Sometimes, the balance weighs against you. With vagaries of the industry, sticking to a strict roster has become a luxury few companies can afford. Finally, it’s the pilot who pays the price of every well-meaning addition of training or compliance that has to be squeezed into your ‘ON’ or ‘OFF’ time.

After a 6-day Aviation Security (AVSEC) course, now they want English Language Proficiency (ELP) training for aircrew. Any guesses who will finally end up losing sleep?

This layer may get added to your McFatigue sandwich unknowingly. Beware.

Effect of Automation

Can there be a common FDTL for fully-automated helicopters like the AW139 or S-92, and non-automated, light singles like the R44 or AS350?

I still recall seeing off a single pilot ferrying a light helicopter out of Juhu, an airfield unfamiliar to him. Juhu, a bird sanctuary with zero navaids, cross-runway, looming shadow of big-brother Mumbai International Airport, complicated ‘Kopter Routeings’, and high traffic density can be intimidating for newcomers. Beads of perspiration streamed down his cheeks as he held a routeing chart in his left hand, juggled around with radio frequencies, read back a complicated departure instruction, and lifted off with no help from man or machine. Once airborne, he would have to negotiate many challenges including weather, terrain and Mumbai’s radar controllers who spew out instructions 90-words per minute.

Juhu airfield during monsoons

How does this compare to modern, twin-engine helicopters that have Pilot Flying (PF) and Pilot Monitoring (PM)? Almost 95% of flying on an air-conditioned AW139 is achieved by turning knobs and pointers. How does a one-size-fits-all FDTL work?

Effect of Cross-flying

As per existing rules in India, there is no separate criteria for FDTL while cross-flying different types of helicopters. Being type-rated on more than one type of helicopter is not unusual, neither is cross-flying two-types (restricted to one type per day). Bear in mind, these two types could be totally dissimilar like conventional / glass cockpit, automated / non-automated, foot-pound versus kilogram-whatever, etc. If crew are detailed to cross-fly as per a predictable routine, there is some safeguard. But when such planning is ad-hoc, can it become another filler in the McFatigue sandwich?

The proof of pudding is not in routine flying, but that day when multiple holes in the cheese align, even if you meet all regulatory compliances for training and currency. A sudden, intense event on high-automation aircraft can excite a ‘startle response‘ from crew. Should the unthinkable happen, will habit interference or fatigue arising out of cross-flying be given its due in the investigation that follows? Regulations evolve with each accident. Who wants to be a data point? And at what cost?

Poor Rest Quarters

Quality of sleep is as important as the quantity of sleep. While rest periods and sleep requirements are well laid out in regulations, quality of sleep is a completely ignored parameter in helicopter circles. Helicopters operate from dispersed locations, often out of reach of the kind of accommodation available to their airline counterparts. There is a need to ensure high quality sleep systems, especially in a country like India where high-decibel noise is a guaranteed by-product of every developmental activity, celebration or festival.

Noise can be a ‘silent stressor’ but do we pay attention to this while providing aircrew accommodation? Do you want to add this slice to your McFatigue sandwich? Chances are, it’s already in there.

Effect of Multiple Sectors

Helicopter pilots operating short, multiple sectors such as during offshore production sorties, heli-tourism, or such other aerial work have been given a generous allowance of 60 landings per day in India (at an average rate of 10 or more landings per hour). Since the last revision of FDTL (2000), all offshore flying in India has to be undertaken under Performance Class 1. Many more safety features, procedures and new equipment have been added since 2000. Yet the FDTL remains unchanged.

On 23 Nov 2015, an AS350-B3 undertaking shuttles to the hill shrine Vaishnodevi at Katra crashed with the loss of seven lives. The pilot of considerable experience was on the 10th shuttle (her first sortie for the day after returning from a 11-day break) when the helicopter ran into wires after a suspected bird hit. She gave it all she got but perished with six passengers.

VT-JKB crash at Katra

The inquiry report (read here) was silent on the likely effect of circadian factors affecting a person returning ex-leave late at night, early start next day, quantity or quality of sleep available prior to undertaking such an intense flying activity and its likely impact on the accident. This should be a clarion call for future investigations to delve deeper into such factors.

Around three weeks before that crash, state-owned PHL lost VT-PWF during an offshore night training sortie (VT-PWF, 04 Nov 2015). The inquiry committee (read report here) of that crash made a recommendation that “pilots should not have any type of allurement to fly more number of hours, which at times may be at the cost of safety”. It’s a grim reminder, often observed in the breach, and pointed out by several investigating boards.

To date, how this figure of 60 landings per day has been arrived at, nobody knows. But the compounded effect of flying 7 hours, 60 landings, within 10 hrs of duty time (fully permitted by rules today) given all the other factors detailed above needs to be reviewed while framing new rules.

Getting the Basics Right

Much of the above can be mitigated if crew are provided with a predictable schedule & facilities that ensure the best conditions for rest and sleep. Quality of sleep is highly undervalued in this industry. Already, a host of sleep-disrupting devices like smartphones and tablets have crept into our bedrooms to ensure that sleep & rest opportunities are not optimally utilised. With WhatsApp and social media, pilots, engineers, controllers, dispatchers, support crew, all could be reeling under a heavy sleep debt.

Benjamin Franklin said “Fatigue is the best pillow”. Well, he was a scientist not an aviator. We don’t need that pillow. Rest periods can be mandated, but certain responsibility must also ‘rest’ with crew for effective off-time management shirking which no FDTL rules can protect us.

It is time we in India also focused on the subtle aspects of fatigue in all our investigations rather than going just by FDTL numbers. It is challenging, but technology is available today to harvest much more data than obtained from a company’s FDTL worksheets. Fatigue cannot be given a casual treatment, even if the direct cause of the accident may appear to lie elsewhere.

‘Knock it off’

In flight testing, any time any crew member felt uncomfortable with the way the test point was proceeding, the ‘knock it off’ procedure could be invoked which meant: abandon the test point and return to safe flight parameters within envelope.

One of the greatest steps taken by DGCA to prevent weather-related accidents on helicopters was the easing of rules on unscheduled landings due weather. No questions would be asked, no judgement will be passed on the crew. Land and live. The good news is that there’s one for fatigue too. It was always there, but seldom invoked. It’s called “I can’t fly because I am too damn tired”.

Instead, the one that is invoked is a customary email from operator to DGCA regularising the FDTL exceedance as per Ops Circular 03/2018. Compare this with a BA 001 (0.01%) reading where a pilot in India would be grounded for three months, licence coloured with red ink with all consequential penalties. How come we condone FDTL exceedance so lightly when research has conclusively established that performance impairment caused due to fatigue is similar to that of having consumed alcohol?

With every new regulation and training capsule blowing another gaping hole in helicopter operators’ balance sheets, crew fatigue limits are bound to be tested. Seeking enhancement to existing FDTL without due consideration to many of the factors detailed above may set ourselves up for events none of us want to see. All stakeholders must look at FDTL as a collective responsibility, going beyond excel sheets and drag-down formulae.

Flying is our bread & butter, our passion. We are here to fly, not to enjoy 5-star hotels or play with our smartphones. But if my McFatigue sandwich is not palatable, I will ‘knock it off’ my table. Don’t expect any explanations or justification. Our safety depends on that.

Good luck with your national rules for FDTL. Indians, hope this motivates you all to have a noise-free, ‘green’ Diwali! Happy landings and sleep well folks!


©KP Sanjeev Kumar, 2018. All rights reserved. Artwork on cover scanned from a flight test handbook of IAF, artist unknown.

Please consult national regulations and your company’s Operations Manual for FDTL as applicable to the type of operation you undertake. Views are personal and do not reflect those of my employer or the industry at large. I can be reached at

4 thoughts on “Aircrew Fatigue – An Indian Helicopter Pilot’s Perspective

  1. Sir,

    Athough the article leaves little room to add, I’ll attempt to contribute to a cause dear to me.

    Indian civil helicopter domain has both employers as well as employees at the bottom of Maslow’s hierachy of needs, primarily the survival domain. Candle burning at both ends only allows ” adjust maadi ” methodology that permits limited possiblity of addressing most of relevant causal factors highlighted in the article.

    Stated ” Knock off/No Go ” philosophy that works almost flawlessly if invoked, must be supported by regulations for protection of crew concerned. Additionally, with available technology, this must be augmented with non intrusive pilot fatigue monitoring devices in cockpit that considers head movement, facial expressions, and physical status (Land vehicle based systems claim to have a success rate of around 85%) to determine fatigue status of subject.

    Business opportunists have even brought in “Pilot fatigue monitoring softwares” that I consider as another number crunching presentation making going more complex for everyone.

    A human dependent process augmented with an independent equipment analogous to deployment philosophy of BA devices should help the cause.

    Finally sir, thanks again for an opportunity to contribute.

    1. You’ve made very valid points. It can only be fixed through an intelligent mix of technology and HFACS considerations.
      For instance, we have mandated in-camera preflight BA checks but done nothing to curb use of psychotropic substances and drugs. Completing preflight medicals during missions such as election flying can leave a pilot tired before even starting the engines. The punitive actions are also very harsh. Maybe medical science can help capture a fatigue reading akin to BA reading 🙂
      A very thought out and scripted response. Thanks, Peeush.

  2. Fatigue and FDTL…FDTL is the maximum permissible figure (super contingency) not a routine….a clause like, on an average no pilot to reach above 85% of this SCR figure permitted…all exceedances to be justified…extensions of FDTL to be sought in exceptional circumstances and that at no stage was extension envisioned during the planning….fatigue makes the brain’s functioning slower with identifiable gaps, poorer cognitive functioning, leading to errors in process of flight management and piloting….fatigue coupled with sleep deprivation aggravates the situation exponentially with perceptible deterioration in cognitive functioning…flights subsequently flown in challenging conditions can be disastrous….it requires legislative changes, sleep management and fatigue monitoring by….I don’t know who….safety is the sum total of man/ machine combination with the man being in charge and not the reverse….the first hint of trouble is when the reverse predominates the flight

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