Flight controls and passengers

November 20, 2012 by Tim McAdams

I was at a state fair several years ago where a pilot was giving helicopter rides in a Bell 206 JetRanger (a 5-seat single engine turbine powered helicopter). What caught my attention was that the dual controls were installed and passengers were being loaded into the left front seat. Allowing strangers access to the flight controls, like when giving rides, is very risky. Even when a pilot knows the passenger, they need to be extremely cautious and give serious consideration as to whether someone is provided access to the flight controls. For example consider the following accident that happened February 14th, 2010.

According to the NTSB, a ranch foreman who observed the flight preparations saw the helicopter owner board the helicopter through the left forward cockpit door and occupy the left front cockpit seat. The helicopter owner’s 5-year old daughter also boarded the helicopter through the left forward cockpit door and sat on her father’s lap. The pilot, who had 11,045 hours of total flight time, all in rotorcraft-helicopters, 824 hours of which were in the EC135 T1, was already seated in the right front cockpit seat. Both the left and right front cockpit seats were equipped with dual flight controls. Operator personnel revealed that the helicopter owner’s daughter had sat on her father’s lap occasionally during flights, that the owner liked to fly the helicopter, and that it was common for him to fly. Although the owner held a certificate for airplane single-engine land, he was not a rated helicopter pilot. However, it could not be determined who was flying the helicopter at the time of the accident.

About 35 minutes after departing the ranch, radar data revealed that the helicopter was about 2,000 feet above ground level when witnesses on the ground stated they heard unusual popping or banging noises. Several witnesses also stated that they saw parts separate from the helicopter before it circled and dove to the ground. The helicopter impacted a river wash area north of the destination airport in a slightly nose-down and slightly left-bank attitude. The helicopter was subsequently consumed by a post crash fire. The accident was not survivable.

A post accident examination of the helicopter revealed that the yellow blade had impacted the left horizontal endplate and the tail rotor drive shaft in the area of the sixth hangar bearing, which resulted in the loss of control and subsequent impact with terrain. No pre-impact failures or material anomalies were found in the wreckage and component examinations that could explain the divergence of the yellow blade from the plane of main rotor rotation. Flight simulation indicated that the only way that this condition could have occurred was as a result of a sudden lowering of the collective to near the lower stop, followed by a simultaneous reaction of nearly full-up collective and near full-aft cyclic control inputs. A helicopter pilot would not intentionally make such control movements.

A biomechanical study determined that it was feasible that the child passenger was seated on the helicopter owner’s lap in the left front cockpit seat during the flight and that the child could fully depress the left-side collective control by stepping on it with her left foot. The study also found that the collective lever’s full range of motion was 9.5 inches from full up to full down and that the spacing between the left edge of the seat, the collective, and the door are sufficient such that a child’s foot could rest on the collective and depress it. The study noted that the cyclic control could be moved to the full-aft position even with a small child of this size seated on the lap of an adult male in various positions.

Considering that the child was sitting on the owner’s lap in the left front cockpit seat, it is highly likely that the child inadvertently stepped on the collective with her left foot and displaced it to the full down position. This condition would have then resulted in either the pilot or the helicopter owner raising the collective, followed by a full-aft input pull of the cyclic control and the subsequent main rotor departing the normal plane of rotation and striking the left endplate and the aft end of the tail rotor drive shaft.

The National Transportation Safety Board determined the probable causes of this accident are:

The sudden and inadvertent lowering of the collective to near the lower stop, followed by a simultaneous movement of the collective back up and the cyclic control to a nearly full-aft position, which resulted in the main rotor disc diverging from its normal plane of rotation and striking the tail rotor drive shaft and culminated in a loss of control and subsequent impact with terrain. Contributing to the accident was absence of proper cockpit discipline from the pilot.

12 Responses to “Flight controls and passengers”

  1. Avi Weiss Says:

    Unless one is providing or receiving dual instruction, the passenger-side controls should be removed.

    Aside from the terrible accident referenced and resulting loss of life and damage incurred as a result of flight control access, should one have an incident ever occur with the duals in, the insurance company will take the position that the only reason duals were left in was to either provide instruction or allow the passenger-side occupant to operate controls. If the passenger is not rated, and/or the pilot is not a current CFI, the insurance company will not cover the accident, as one of two FARs was violated: control manipulation by an unrated pilot or illegal instruction.

    Bottom line: remove the passenger side controls unless you are instructing, or the passenger is rated AND current.

  2. Keith Mendoza Says:

    I’m a Private SEL with no helicopter experience so I don’t know if this would apply. My personal “rule” is that kids do not sit in the front seat unless I can trust them to follow instructions accordingly. I personally believe that if the child can or should sit in an adults lap, they belong in the back, period no excuses. I also believe that kids get hurt because they’re curios, so let them look and feel around for a bit; they’ll get over it quickly and will be more willing to sit quietly in the back and look out the window.

  3. Jim Borger Says:

    Think about this. Almost every airplane out there has duals installed with non-pilot passengers regularly sitting in the co-pilot seat. How many of them crash because of passengers interfering with the controls? I have thousands of hours in both rotory and fixed wing with non-pilots occupying a seat with controls. I throughly brief them before cranking up and never have a problem. The only problem I have ever had was in a BO-105 with the duals removed. I had a full load and was in cruise flight when the collective suddenly dropped halfway down and moderate up pressure had no effect. I slowed to Vy and was slowly losing altitude so I slowly increased up pressure on the collective with no effect. I looked down to see if something was blocking the control and saw a large foot planted in the middle of the collective. One of the backseat passengers had decided he wanted to put his foot up and the collective looked like a good place to him. I got his attention by smacking his shin and the problem was solved.

  4. Tom Says:

    This report is really a stretch, IMO. Why would the pilot pull full aft cyclic simply because he was raising an accidentally lowered collective?? The NTSB is reaching on this one. I’m surprised they didn’t blame the child for the full aft cyclic pull.
    The ship was consumed by fire so the phrase “no anomolies were found” is key here. The NTSB could have overlooked something or more likely, the cause of the wreck was destroyed in the fire.
    Blaming the accident on a child lowering the collective and the pilot for then raising the collective to full up position while he also pulled full travel aft cyclic is bull feathers. This was a 10,000 plus hour heli pilot and they were flying at 2,000 agl.
    Baloney on this report is what i say.

  5. Stan Lee Says:

    I agree with Tom , seemssomeone wanted to close the file

  6. Paul Says:

    I agree with Tom, but I have another thought on this and like to believe the NTSB would look at this case again. The article stated that the owner was not a rated helicopter pilot, so we really don’t know his level of training/competence in helicopters. Lets entertain the idea, just for a minute, that the child did step on the collective sending it to the downstop. For a helicopter pilot this is not a big deal. Gently slow up and bring the collective back in. When the child stepped on the collective and the helicopter started to decend I think it was more possible that the owner grabbed the cyclic and pulled full aft which is the recovery method for a decending AIRPLANE. We all know that this does not work in a helicopter. He possibly locked up on the controls so that the rated pilot could not move them. The owner was a rated airplane pilot and recovery techniques are NOT the same.

  7. RCL Says:

    I concur with Tom assertion, there is no way such a high time pilot would have made such a “rookie/novice” error.

    The NTSB missed it on this one.

    I would suggest that the child may have slipped and in an attemp to regain balance grabbed the cyclic, perhaps after slipping ( with her foot) off the collective.

    Bad news…..kids should never be up front and never on someone’s lap.

  8. Daniel L. Lieberman Says:

    This is pilot error. His hand should be on the collective at all times and he should know how to recover from a low g pushover – gradually not rapidly. I agree that his failure to recover properly was secondary to his failure to remove the controls if he was a current CFI or his failure to require the 5 year old to be in a rear seat.

    This was mast bumping and should not have occured even with the low g pushover.

  9. ahp Says:

    If you are going to post please be informed. The EC135 rotor system is such that mast bumping isn’t an issue.

  10. Bill Says:

    I am a military helo pilot who does not have civilian passengers in the front seat. From my 3,000 hour experience (even if I were not in a military aircraft), I WOULD NEVER allow 2 people to occupy the same seat in the cockpit where dual controls exist. My take on the NTSB final report was that proper cockpit discipline from the pilot (allowing the child to sit on the lap on a person in the left seat) was a contributing and possibly main factor. That is where the pilot was to blame for the accident. The NTSB does not say that the pilot suddenly and inadvertently manipulated the controls, which caused the rotor blade to contact the tail rotor drive shaft. Just like others have stated, the child could have inadvertently stepped on the collective and with the sudden drop in altitude the child or passenger, out of reaction, grabbed for the cyclic and pulled it aft. The pilot was unable to counter the quick control movements and the chain of event continued to unfold.
    I do not see a problem with riders occupying the left seat with dual controls. As Daniel stated, the pilot has to know his crew/passengers and ensure he/she guards the controls during every evolution at all times.

  11. John Says:

    I agree with earlier posts that the NTSB is stretching the limits of what they could actually determine. Their scenario is plausible but they should emphasize that nothing conclusive could be determined. That said I would say that the pilot was bowing to the wishes of the owner by letting the girl sit up front even though he knew it was against the regulations and against good safety practices. Flying for private owners can be very rewarding but you have to know how to gently assert yourself as PIC while at the same time allowing the owner to enjoy his aircraft. It is a very careful balancing act.

  12. Mike Stinnett` Says:

    Avi Weiss, under FAR Pt.91, there is no FAR prohibiting a non rated passenger from manipulating the controls even with a non-CFI as the PIC. It’s perfectly legal for a private pilot to allow a non-pilot to fly the aircraft. It doesn’t qualify as “illegal instruction”

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