POST OFFICE BOX 90808

 LAFAYETTE, LOUISIANA 70509 USA

 TELEPHONE: 337 235 2452

 FACSIMILE: 337 272-4510

September 20, 2011 Also Filed Electronically

U.S. Department of Transportation

Docket Operations

West Building Ground Floor, Room W12-140

1200 New Jersey Avenue, SE

Washington, DC 20590.

To Whom It May Concern;

In accordance with CFR 14 11.15 and 11.81, PHI, Inc., requests an exemption from Part 91.9(a) 

which, in part, states:

Except as provided in paragraph (d) of this section, no person may operate a civil aircraft 

without complying with the operating limitations specified in the approved Rotorcraft Flight 

Manual, markings, and placards, or as otherwise prescribed by the certifying authority of the 

country of registry.

Extent of Relief Sought and Reason for the Relief

This petition requests an exemption from the following S-92A Rotorcraft Flight Manual limitation 

when operating between land-based and offshore facilities or when operating between two offshore 

facilities. 

TYPES OF OPERATION

Category ’A’ with a maximum of 19 passenger seats or Category ’B’ with 9 or less passenger 

seats; Day, Night, VFR and IFR.

Specifically, PHI, INC. requests approval to operate S-92A helicopters with limited exposure to engine 

failure during takeoff and landing while carrying up to 19 passengers.

This Exemption is in the Public Interest

The S-92A, and other 10+ seat rotorcraft certified to the latest standards (FAR 29 amendment 47) and 

equipped with state-of-the-art safety systems and technology, routinely transport workers to and from 

offshore platforms to support the oil and gas industry. Specifically, equipment such as HUMS, 

HTAWS, ADS-B, TCAS/TAS, FMS, Fault Tolerant Design and other advanced avionics and 

electronics allow these rotorcraft to offer the highest level of safety available today. These aircraft 

replaced older designs which do not offer these advancements, and not required to meet the current 

performance requirements imposed on the S-92 and other similar aircraft. The intent of this exemption 

is to provide those workers with the safest transportation available, while maintaining an efficient 

transportation system for the oil and gas industry.

For these reasons, this exemption is in the general public interest.
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

Equivalent Level of Safety

The S-92A has operated under Operations Specification H100 in the United States, and under JAROPS 3 in other countries, since 2003. Both rules allow for limited exposure to engine failure. The 

requested exemption will continue to provide the same level of safety that is currently in place for 

offshore operations. During the period noted above, no accidents (S-92A or other aircraft in the same 

class) have been caused by power loss due to engine failure during takeoff or landing.

If this exemption is granted, the S-92A will continue to operate Category A with the exception of a 

brief exposure to engine failure during takeoff and landing. The amount of time the aircraft is exposed 

to engine failure will depend on many conditions, but the maximum exposure would normally be less 

than 9 seconds per takeoff/landing. 

If this exemption is not granted, the S-92A (and other like aircraft) would be forced to severely 

decrease the number of passengers and/or fuel per sortie. Decreased passenger loads will require more 

sorties to meet demand and effectively increase exposure to hazards unrelated to engine failure. A 

discussion on the merits of limited exposure to engine failure during offshore operations, explaining 

how the overall level of safety may be enhanced by the requested exemption, is provided as 

Attachment A to this petition.

Operations Outside of the United States: 

Non-U.S., S-92A operators outside of the United States do not require this exemption. JAR-OPS 3, 

and other equivalent operational rules, already permit operations with limited exposure to engine 

failure.

PHI, Inc., wishes to have this exemption apply to their operations outside the USA for the same 

reasons stated herein.

Mitigation Factors:

In the unlikely case of a ditching as a result of an engine failure during takeoff or landing, the 

following mitigation is provided:

• The S-92A is equipped with aircraft flotation gear and is certified for ditching in up to sea 

state 4.

• When operating over water, each S-92A occupant is provided, and wears, personal flotation 

equipment.

• The S-92A is equipped with life rafts that can be deployed from inside or outside the 

aircraft.

To qualify for JAR-OPS 3 Performance Class 2 operations (limited exposure to engine failure), 

Sikorsky Aircraft periodically submits engine reliability reports to show that the in-flight shutdown 

rate is less than 1 per 100,000 flight hours. The most recent report, dated March 28, 2011 supports 

continued PC 2 operations.
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

PHI, Inc., will conduct operations in such a manner as to minimize the time spent exposed to engine 

failure. This will be accomplished by following the manufacturer’s recommended takeoff and landing 

procedures whenever feasible. Operations will not be conducted unless the current aircraft weight, 

altitude and temperature ensure a 100 feet per minute climb at 1,000 feet above the takeoff surface 

with one engine inoperative and the remaining engine at maximum continuous OEI power.

PHI, Inc., further mitigates exposure by;

• Conducting flight operations to and from helidecks and shore based heliports that meet or 

exceed size and weight requirements appropriate to the aircraft configuration.

• Training our crews in a Level D, FFS (Full Flight Simulator) initially and annually, insuring 

the highest levels of proficiency and competency.

• Conducting route checks to confirm that our crews remain procedurally compliant and use 

CRM principles during all flight operations.

• Using PHI's Flight Data Monitoring Program (known as LAMP) to insure flight profiles are 

in accordance with PC-2 procedures.

Summary

PHI, as the launch customer for the S-92, has accumulated over 60,000 hours of operational experience 

in this make/model all in accordance with H-100 and Performance Class 2 profiles. This experience

demonstrates that when takeoff and landing techniques are used to minimize exposure to forced 

landing due to engine failure, that this aircraft can be operated at an equivalent level of safety to

Category A (PC-1).

Due to the remote nature of our operations, helideck size and off-airport basing, the viability of full 

Category A or Performance Class One (PC1) is impractical. If this requirement were to be imposed, 

the S-92 (and its equivalent competitor aircraft) would become economically unfeasible which likely 

would result in their removal from service. The outcome would be a reversion to smaller, older, less 

sophisticated aircraft that do not provide the same level of safety. This would result in an overall 

degradation of safety and not serve the most important stakeholder...the passenger.

If there are any questions concerning this petition, or to report the disposition of this request, please 

contact me as indicated below.

Sincerely,

Michael C. Hurst

Chief Pilot, PHI, Inc.

P.O. Box 90808

Lafayette, LA 70509

337.272.4242

email: mhurst@phihelico.com

Attachment
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

INTENTIONALLY BLANK
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

Attachment A Page | 1 of 7

Attachment A

The Case for Limited Exposure to Engine Failure

Sikorsky Aircraft uses a hazard identification/mitigation process that identifies the hazards 

involved in each area of operation and then uses different mitigation processes to drive the risk 

down to the lowest possible level. In the rare case where the mitigation process for one hazard 

adversely raises the risk of a different hazard, the mitigation must be applied to the most likely 

accident scenario. 

The following discussion examines the offshore takeoff and landing maneuvers, identifies the 

historical hazards associated with these maneuvers, and assigns appropriate mitigation processes 

to each hazard. 

Offshore elevated helideck takeoff procedure.

Figure 1

Published S-92A Elevated Helideck Takeoff Procedure
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

Attachment A Page | 2 of 7

Figure 2.

Typical Elevated Platform

The no-exposure takeoff from an offshore elevated helideck (Figure 1) is initiated by adding 

power to establish a vertical climb. The takeoff decision point (TDP) is defined as a height 

above the takeoff surface with a corresponding vertical velocity at that height. For the S-92A, 

the TDP for an elevated helideck is 30 feet with a 1,000 fpm climb rate. If an engine should fail 

prior to the TDP, the takeoff is rejected and the aircraft lands back on the helideck. If an engine 

should fail at or after the TDP, the takeoff is continued and the aircraft flies away. When this 

procedure is flown at the appropriate weight for the given ambient conditions (pressure altitude, 

temperature and helideck height) the aircraft has no exposure to engine failure. - i.e. an engine 

can fail at any point in the procedure and the aircraft can either safely land back on the helideck 

or continue the takeoff and fly away on the remaining engine. There are two primary hazards 

associated with this maneuver.

Takeoff hazard 1

 

: Contact with the platform structure with All Engines Operating (AEO).

The takeoff procedure is very dynamic. The pilot is required to attain a fairly high climb 

rate in a short period of time while maintaining position directly over the helideck. 

Visual cues for position maintenance are limited under the best of conditions and quickly 

degrade in poor weather or at night. As the aircraft climbs, there is a tendency to drift aft 

in an attempt to keep the edge of the helideck in sight. If the pilot drifts backwards, the 

aircraft main or tail rotor may contact the offshore platform structure. Note the 

proximity of obstacles in Figure 2.

Mitigation: Lower the TDP height and vertical velocity. 
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

Attachment A Page | 3 of 7

Decreasing the TDP height to 15 feet allows the pilot to keep the helideck edge in sight 

and decreases the time spent in close proximity to the rig structure. Decreasing the TDP 

vertical speed to 500 fpm makes the maneuver less abrupt and easier to fly.

Takeoff hazard 2: Engine failure during takeoff.

Large transport (19 passengers) helicopters do not have sufficient power to hover on one 

engine when at normal takeoff weights. If an engine should fail at, or immediately after 

TDP, the takeoff procedure described above takes advantage of vertical velocity energy 

and the energy gained by dropping down below the helideck to attain a safe One Engine 

Inoperative (OEI) speed (VTOSS). If sufficient energy is not available at the critical point, 

the aircraft is exposed to hitting the deck edge or ditching in the water below the 

platform.

Mitigation: Increase the TDP height and vertical velocity.

A higher TDP height and vertical velocity provides more energy for a subsequent fly 

away maneuver if an engine should fail at or immediately after the TDP. In addition, it 

should be noted that, as the helicopter weight decreases (lower fuel/payload), the 

exposure to engine failure decreases due to increased OEI power margins.

It is clear that the mitigation factors for each of the two hazards are diametrically opposed, the 

AEO hazard being mitigated by a lower TDP with a slower initial climb rate, and the OEI hazard 

being mitigated by a higher TDP with a higher initial climb rate. 

The hazards associated with lowering the takeoff weight are discussed later in this paper.
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

Attachment A Page | 4 of 7

Offshore elevated helideck landing procedure.

Figure 3

Published S-92A Elevated Helideck Landing Procedure

The landing procedure requires an offset approach with an aim point that is one to two rotor 

diameters to the side of the target helideck. The S-92A no-exposure approach is flown at an 

indicated airspeed no slower than 40 knots with a descent rate no greater than 600 fpm. At 50 

feet above the helideck, a flaring side step maneuver slows the aircraft to a hover while placing 

the aircraft over the landing spot. The Landing Decision Point (LDP) is 50 feet above the 

landing surface with at least 40 knots airspeed and no more than 600 fpm descent rate. If an 

engine fails prior to the LDP, the pilot flies a go-around maneuver, dropping below and to the 

side of the platform. If an engine fails at or beyond the TDP, the pilot performs an OEI landing 

on the helideck. The two primary hazards during a landing are very similar to those associated 

with an elevated helideck takeoff ; AEO contact with the platform and OEI deck edge strike or 

ditching.

Landing hazard 1: Collision with the platform structure with all engines operating (AEO). 
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

Attachment A Page | 5 of 7

If zero exposure to engine failure is mandated, the pilot must fly the OEI profile every 

approach, just in case an engine fails at the most inopportune time. A single engine 

landing to a small platform (60 - 100 foot diameter circle) requires a very dynamic 

maneuver involving an aggressive pitch rate and high pitch attitude. Under the best of 

conditions, this type of maneuver, in close proximity to the obstructions associated with 

an offshore platform, is challenging. When the degraded visual cues of a night mission, 

along with the turbulence associated with the rig structure, are considered, the chances 

for error are greatly increased. This dynamic AEO landing procedure is the cause of 

many offshore accidents.

Mitigation: Reduced approach speed

Reducing the approach speed results in a much lower pitch attitude during the flare and 

consequently a less aggressive maneuver. A 10 knot ground speed provides a safer, more 

controlled approach.

Landing hazard 2: Engine failure during landing.

As noted in the takeoff discussion, the aircraft under discussion do not have an OEI hover 

capability at the desired operating weight. The helicopter requires sufficient airspeed to 

minimize the power required to avoid contact with the water if the engine should fail 

prior to the LDP. The kinetic energy associated with this airspeed is also required to 

carry the aircraft over the landing surface if the engine should fail at or just after the LDP. 

Mitigation: Increased approach speed

A 40 knot approach speed is required to ensure sufficient energy for a fly-away maneuver 

(engine fails prior to LDP) or successful landing (engine fails at or after LDP). Again, it 

should be noted that, as the helicopter weight decreases (lower fuel/payload), the 

exposure to engine failure decreases due to increased OEI power margins.

Again, the mitigation factors for the two primary landing hazards are opposite. A slow approach 

speed is required for an easily flown, controlled approach which will decrease the chances of 

AEO contact with the platform structure. However, a faster approach speed provides the energy 

required to perform a successful OEI fly away or landing.

Decreased gross weight. 

In both the takeoff and landing maneuvers, a lower aircraft gross weight will improve single 

engine performance and decrease the hazard of an OEI accident. However, decreasing the 

aircraft gross weight can only be accomplished by decreasing the passenger or fuel load.

Hazard of decreased passenger load: The total number of passengers exposed to an 

accident does not change. 

A decreased passenger load on each sortie will require additional sorties to be flown to 

service the offshore oil fields. With the current fleet of aircraft operating in the Gulf of 

Mexico, if flight with no exposure to engine failure was mandated, the number of sorties 
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

Attachment A Page | 6 of 7

required would at least double. Each additional sortie increases the likelihood of AEO 

accidents caused by Controlled Flight Into Terrain (CFIT), mid-air collision, or 

mechanical failures. 

Hazard of decreased fuel load: Fuel starvation and increased take-off and landing activity.

There are two concerns with a decreased fuel load. 

1. The knowledgeable pilot will carry more than the minimum required fuel as insurance 

against the changing offshore environment. If required to minimize gross weight, 

there will be increased pressure to launch with the absolute minimum fuel required. 

Due to changing weather conditions, this will certainly lead to landings with fuel 

levels below the required minimums and the associated possibility of ditching due to 

fuel starvation.

2. For longer range missions, what would normally be a “non-stop” flight will require an 

intermediate fuel stop going to and returning from the intended offshore destination. 

These additional (unnecessary) offshore takeoffs and landings also increase the 

likelihood of the AEO accidents noted above.

The Dilemma:

The mitigations for the All Engines Operating (AEO) hazards are directly opposed to the 

mitigations for the One Engine Inoperative (OEI) hazards. 

In order to minimize the AEO hazards, it would be necessary to:

1. Fly slow controlled approaches (15 knot ground speed) 

2. Utilize lower takeoff decision points (15 feet at 500 fpm climb rate)

3. Maximize passengers on each sortie to minimize the number of sorties

4. Carry additional fuel reserves to minimize additional offshore landings and takeoffs 

to refuel

In order to minimize the OEI hazards, it would be necessary to:

1. Fly faster approach speeds (40 KIAS)

2. Utilize higher takeoff decision points (30 feet at 1,000 fpm climb rate)

3. Minimize weight by off loading passengers and fuel.

4. Add offshore refueling stages to the mission

The offshore oil industry reviewed these hazards to determine the safest route forward. They 

identified the hazard which, historically, has been the major contributor to accidents and then 

addressed that hazard. The issue may be summarized as determining whether there are more 

accidents caused by pilot error with all engines operating or by the loss of power due to a single 

engine failure.

A review of the last ten years of worldwide helicopter offshore operations yields eight instances 

of pilot error; AEO accidents in which the aircraft struck some portion of the platform. There 
PHI, Inc.

Petition for Exemption to 14CFR 91.9(a)

September 20, 2011

Attachment A Page | 7 of 7

were also at least four instances in which pilot error resulted in an inadvertent AEO 

ditching/crash into the water. During that same ten-year period, there were no accidents caused 

by the loss of power due to engine failure on multi engine aircraft.

The best route forward is clear. The chances of an accident caused by pilot error with AEO is 

much greater than the likelihood of an OEI accident. Procedures that minimize the opportunity 

for pilot error and permit limited exposure to engine failure provide the highest level of safety. 

Procedures, such as Performance Class II (PC-2) have been proven worldwide to offer an 

equivalent level of safety as compared to Category A or PC-1 profiles.

Recommendation.

The FAA should approve this request for exemption from Part 91.9(a) to permit limited exposure 

to engine failure when operating in the offshore environment or in other areas where exposure 

can be minimized using accepted takeoff and landing profiles.