|The opinions expressed and recommendations included in this article are those of the author and are not necessarily endorsed in whole or part by Equipped To Survive. Equipped To Survive presents this information as a public service, but has not verified any of the information contained herein.|
Richard L. Newman
6 November 1986
Revised 12 June 1994
Published in SAFE Journal 18: Number 1, Spring 1988, pp.
reprinted in SASI Forum 22: May 1989, pp. 1-19
CREW SYSTEMS CONSULTANTS
Post Office Box 963
San Marcos, Texas 78667
Cessna U-206F, N-1803Q, ditched in the Potomac River at 0718 EDT on 24 May 1985 during a flight from Springfield, Ohio to Patuxent River NAS, Maryland. The ditching occurred during daylight approximately 12 nm southeast of Patuxent River NAS in the mouth of the Potomac River approximately 3/4 mile from shore. The writer, the sole occupant of the airplane, was not injured. The airplane, undamaged during the landing, sank and was damaged beyond economic repair by immersion in salt water. This paper presents a historical review of US civil aircraft ditchings and discusses various aspects of ditching light aircraft. Several recommendations have been made as a result of this accident, including the need for videomaps of shorelines on ATC radar and the need for better ditching instructions in aircraft handbooks.
N-1803Q departed Springfield, Ohio, at 0432 EDT for a flight to Patuxent River NAS, Maryland. The flight was conducted under instrument flight rules at a cruising altitude of 15000 ft. No engine or systems discrepancies were noted throughout the flight. During the last half-hour of the flight, the airplane descended to 11000 ft to avoid moderate clear icing. The anti-icing system was used with no problems noted. While on radar vectors for a GCA to Patuxent River NAS, at about 3800-4000 ft in clouds, the engine seized. Fuel tanks were switched and an engine restart attempted. Power could not be regained. The cabin then began to fill with smoke from the lower right hand forward area. After securing the engine, air traffic control (ATC) was advised power had been lost with smoke and a possible fire. ATC provided a vector to the nearest airport and advised that it was eight miles away. Altitude at this point was 2500 feet, still in clouds. ATC then advised that the aircraft was over water and provided a radar steer toward the nearest land. A water landing was made with flaps retracted at minimum speed. The ditching occurred at 0718 EDT during daylight hours. The accident location was approximately 12 nm southeast of Patuxent River NAS in the mouth of the Potomac River at 38 deg 12.5 minutes North and 76 deg 36 minutes West, approximately 3/4 mile from shore.
The engine failure occurred while flying in clouds at about 4000 ft. The airplane was being vectored in the general direction of the shoreline as it descended. The first symptom of the failure was noticing that the propeller had stopped. Because the engine had seized, no power was available to the attitude and direction gyros. I used the turn coordinator the primary attitude reference while in clouds. ATC provided radar vectors towards shore. The airplane became clear of the clouds at 1000 ft. I requested helicopters several times. At about 500 ft, ATC said that radar contact had been lost. I asked for a wind check. The landing was made into the reported wind (which appeared to agree with wave action). No swells were observed. I removed my eyeglasses prior to ditching. I landed with flaps retracted at minimum speed. There were two light skips and the nose dove down. Subjectively, the forces were surprisingly light. When the nose dove low on impact, water broke through the windshield. The airplane came to rest upright, about 20-30 degrees nose low with water coming in over the cowling through the broken windshield. I unfastened the harness and attempted to exit via the front door. There was some difficulty with the parachute leg and chest straps. I couldn't open the main cabin door. (I had not unlatched the door prior to touchdown.) Egress was made by climbing over the pilot seat back to the cargo door, opening the cargo door, and jumping out. The top of the wing was about six inches above the water at the time I entered the water. I climbed on top of the aft fuselage and observed two boats about 3/4 mile away coming toward the airplane. The airplane sank in less than one minute after impact. While flotation gear was on board, the airplane sank before I could locate the life jacket from the rear of the aircraft. Two boats and several helicopters arrived after about ten minutes in the water. Shortly thereafter, a Navy helicopter hoisted me aboard and provided transportation to the Patuxent River NAS hospital.
I had landed with the flaps retracted in order to judge the flare better. However, the divers' report of the wreckage shows the flaps were at 5 or 6 degrees and the flap selector was positioned to 20 degrees. The landing had been made with the master switch on (to maintain communications) and it was only turned off after landing. There was some noise after landing which may have been the flaps extending. This noise stopped following turning the master switch off.
The photograph below of the wreckage (an underwater photograph of the cockpit) shows that the impact forces bent the throttle (first engine control on the left) to the right (my hand was on it) and probably caused my hand to strike the flap handle moving it to the 20 degree point.
The cargo door and the flaps interfere with each other. The cargo door cannot be opened if the flaps are down and the flaps are prevented from extending if the door is open. The 5 degree position that flaps ended up at is the lowest they can be extended and still allow the door to open.
A list of ditching accidents from 1979 through 1983 was obtained from NTSB computer files. A total of 214 accidents were found. These accidents are listed in the appendix. The numbers of accidents and the injury index are shown below in Table I.
The severity of the ditching accidents is difficult to assess from this computer listings. The most logical severity index for land accidents would be the percent of accidents in which the aircraft was destroyed. This index may not be suitable for ditchings since even no-damage landings can result in airplane write-offs when the airplane sinks. We shall use as our index of severity, the percent of water accidents that result in fatalities. We must be careful with this choice, since fatalities may result from impact injuries, from an inability to exit the airplane, drowning, or exposure. Impact injuries or egress difficulties may depend on aircraft characteristics, while drowning or exposure fatalities are probably more influenced by the amount of survival gear carried and the availability of rescue aid. Nevertheless, we shall use as our index, the percent of ditchings resulting in fatal accidents as our key, recognizing these limitations. Overall, the US civil fleet experienced 214 ditchings (CY 1979-1983) of which 34 were fatal. Thus 16 percent of all ditchings result in fatalities. The types of aircraft involved in these accidents and the percent of the "ditchings" that are fatal are shown below in Tables II and III.
|Light Single Engine||144||18||13|
|All Types of Airplanes|
|High Wing, Fixed Gear||79||8||10|
|Low Wing, Fixed Gear||38||6||16|
|High Wing, Retract Gear||33||7||21|
|Low Wing, Retract Gear||64||13||20|
|Total (All Types)||214||34||16|
|S/E Certified Airplanes Only|
|High Wing, Fixed Gear||77||8||10|
|Low Wing, Fixed Gear||25||5||20|
|High Wing, Retract Gear||19||4||21|
|Low Wing, Retract Gear||23||1||4|
|All High Wing||96||12||12|
|All Low Wing||48||6||12|
|All Fixed Gear||102||13||13|
|All Retract Gear||42||5||12|
|Total (S/E Certified only)||144||18||13|
Other than the greater percent of fatal ditchings experienced by transport category airplanes (X2=9.21, p<.01), no particular airplane configuration (high or low wing, fixed or retractable gear, single or multi-engine) or category (normal, restricted, experimental, or military surplus) appears to stand out as shown in Table III. No individual aircraft model has a statistically significant fatality percentage during ditchings. While low wing retractable gear airplanes appear to be high in terms of fatal ditchings, this is confounded by the presence of high performance airplanes having to this configuration. Night ditchings have a less favorable chance than day ditchings. Twenty five percent of night ditchings resulted in fatalities (48 out of 195). This may be a result of difficulties in landing or in water survival or rescue at night.
Ditchings are not confined to traditional overwater operations. Sixty three percent of all civil ditchings occur during non-overwater operations. Table IV below shows this clearly. We have labeled certain operations as marginal overwater. These include flights along the Florida Keys and similar locations where crewmembers and passengers are likely to be exposed to water landings in the event of an forced landing. We have also included intentional offshore commercial operations as overwater even if the 50-miles-from-land rule doesn't apply.
|Overwater or Not||Number
|Marginal Overwater (a)||11||1||9|
|(a) Operations along the Florida Keys, etc.|
(b) Includes intentional offshore banner towing, fish spotting, etc.
even if less than fifty miles off shore.
Other Ditching Studies
The literature of aircraft ditchings is fairly sparse. (see the bibliography) Most general aviation ditching papers are anecdotal accounts of particular ditchings. Snyder and Gibbons (1) reviewed NTSB ditching statistics for the period 1964-1974. Their conclusions were that the fatality rate (based on numbers of fatalities, not numbers of accidents) was about 12.5 percent. This is quite similar to our findings. They further suggest that one-half of the fatalities are related to water survival, not impact injuries. They also observed that fixed gear airplanes are less successfully ditched than retractable gear airplanes and that multi-engine airplanes have a statistically significant higher fatality rate than single-engine airplanes.
Snyder (2) reviewed transport airplane ditching statistics. He also presents case histories of four ditchings (three unintentional) of jet transport airplanes. Among other conclusions, he estimates the deceleration forces during the intentional ditching (of a DC-9) as approaching the 9g design strength of the passenger seats.
Most general aviation airplanes have no ditching instructions in their flight manuals. The GAMA specification for Pilot Operating Handbooks (POHs) only requires water landing procedures for aircraft with extended overwater capability (3). Extended overwater operations are defined in FAR 1 as any flight involving a distance of more than fifty miles from land (4).
A review of several general aviation handbooks showed that only Cessna included ditching discussions in their emergency procedure section of the POHs for single engine airplanes. Other manufacturers do not present any procedures or discussions in their POHs. The following was taken from the Cessna handbook for N-1803-Q: (5) Section 3: Emergency Procedures FORCED LANDINGS
Other Cessna POHs for single engine airplanes have similar ditching procedures as N-1803Q. Later models have amplified procedures with additional discussion.
General Ditching Techniques
The ditching checklist for the Cessna N-1803Q (5) emphasizes the no-flare touchdown. Implicit in these instructions is the availability of power. For a single-engine airplane, such as for N-1803Q, it seems that the most likely cause of a water landing would be complete power failure with no choice for another landing site. Because of this, we will examine appropriate ditching techniques. Virtually all authorities discuss landing in conditions of heavy waves or swells. Oddly, at the same time, many seem overconcerned about the glassy water situation which would make judging height above the surface difficult. For example, Kershner says:
Don't try to second guess and flare when you think it's time. You may level off too high and drop in a nose-down attitude -- this will generally insure an unsuccessful ditching. Also if the tail is too low on impact, the result may be a pitching forward and digging in. It is very hard to judge altitude over water, particularly in a slick sea (6).
Discussions with flight test personnel regarding the need for a flare indicate that Cessna has chosen to emphasize Kershner's position regarding the difficulty of judging height above glassy water.
The Coast Guard reference states that a flare is necessary for a safe ditching.
If no power is available, a greater than normal approach speed should be used down to the flare. This speed margin will allow the glide to be broken early and more gradually, thereby giving the pilot time and distance to feel for the surface -- decreasing the possibility of stalling high or flying into the water (7).
The National Transportation Safety Board (NTSB) has commented on the need to fly as normal a touchdown as possible.
A well-executed water landing probably involves less deceleration violence than ... a touchdown on extremely rough terrain .... A fixed wing aircraft that is ditched at minimum speed and in a normal landing attitude will not sink like a rock upon touchdown (8).
While intended for pilots flying transport airplanes, one airline's general ditching principles emphasize the value of power and the need to maintain the proper landing attitude.
The value of power in ditching is so great that the pilot should always ditch before fuel is quite exhausted.... The two factors of utmost importance in the actual touchdown are picking the point of landing and maintaining the proper landing attitude .... Hold off touching down until all excess speed above stall has been dissipated. The aircraft should contact the water with the nose 5 - 10 deg high.(9)
It is worth observing that I obtained a seaplane rating approximately two years prior to the accident. During the oral examination for the rating, the question of how to conduct a forced landing on glassy water in a seaplane was raised. The examiner stated that it was quite impossible to make a successful power-off landing on glassy water and that the forced landing should be made on land.
The problem in drafting emergency procedure steps is to develop procedures that can handle all situation adequately even though some situations might not be handled optimally. The problem with Kershner's procedure is that it (in our opinion) emphasizes the glassy water case too much (a situation for which is probably not possible to develop safe procedures) and pays less attention to the power-off forced landing in water. The instructions in N-1803Q's handbook for ditching are really instructions for an intentional water landing, more in the category of a precautionary landing which happens to be in the water.
Two points are worth emphasizing during water landings. One is to achieve the slowest practical speed. The second is to have the nose up rather than in a normal glide. With power available, these can be achieved using the published procedures.
Most single engine airplane water landings occur because of complete engine failure, not because of intentional ditchings. Thus they fall more into the category of forced landings in water. This is borne out by the statistics from the review of NTSB ditching accidents. The NTSB has also published a special study which indicates that most air carrier "ditchings" are, similarly, unintentional water landings.(10) Table V below shows this quite well. In the absence of power, the flaps may have a tendency to (a) cause the airplane to fly at a lower nose attitude, (b) descend more steeply making it less likely for the pilot to reach the shoreline, and (c) make it more difficult to judge the flare. This is to be weighed against the slower stall speed achievable with flaps.
Ditching procedures should be divided in terms of power-on and power-off ditchings. The power-on discussion should be left essentially intact with the possible addition of some discussion about the extreme benefit of power and additional discussion on the need for a proper nose-high attitude with the power set for a minimum sink rate. The power-off ditching procedure should consider using a no-flap minimum sink speed glide (or perhaps slightly faster) with a two step flare. Further, both sets of procedures should mention the need to keep the wings level with the water if landing parallel to the swell.(7)
|All Types of Airplanes|
|Ditched: No Power||183||86||29||16|
|Ditched: With Power||20||9||2||10|
|Ditched: Single Eng||9||4||1||11|
|Total (All Types)||214||100||34||16|
|S/E Certified Airplanes Only|
|Ditched: No Power||145||93||16||11|
|Ditched: With Power||9||6||0||0|
|Total (S/E Only)||156||100||18||12|
High wing airplanes should attempt to land with no crosswind drift. The crab should be kicked out with rudder just prior to touchdown. This is more important with high wing aircraft, for they are laterally unstable on the water in a crosswind and may roll to the side in ditching."(7)
The position of wing flaps and landing gear should be modified by particular aircraft characteristics. Generally for most airplanes it is recommended that all ditchings be made gear up.
Recommended Ditching Procedures for S/E Airplanes
The following procedures are intended for a typical high-wing, fixed-gear, single-engine airplane. Normal approach speeds of 70-80 KIAS (flaps up) and 60-70 KIAS (flaps down) are assumed.
Section 3: Emergency Procedures
There was flotation gear (a life vest) aboard N-1803Q. However, it was stored at the rear of the airplane. It should be emphasized to pilots that flotation gear that is well hidden is not very useful. Further, most pilots do not feel that flotation devices are required for domestic flights. However, the accident statistics show that only 32% of ditching accidents occur during overwater operations. Also, most of these overwater operations did not require that any flotation gear be carried on board since they were "not for hire" operations. The lack of concern for the need for flotation gear among the pilot population should be addressed.
Furthermore, the types of equipment that is required under the category of "life rafts" and "life preservers" varies from rule to rule. In particular, it is not at all clear why life rafts for commuter airlines (FAR 135) need contain such specific items as police whistles while airline (FAR 121) rafts only specify "a survival kit." We feel that the extreme variation in types of equipment and in distances specified in the rules (i. e. beyond gliding distance, beyond 50 nm, and beyond 100 nm) is confusing and should be simplified. Since most ditchings are, in fact, unplanned forced landings, even for air carriers, the 50 and 100 nm rules may be obsolete.
Existing requirements for water survival gear is outlined below in Table VI.
|Distance From Land|
|For Hire||None||FG / SD||FG / SD||FG /SD|
|Air Taxi||None||FG / SD||LP/LR1/SD||LP/LR1/SD|
|Corporate||None||None||FG||LP / LR2|
|Airline||None||FG / SD||LP/LR2/SD||LP/LR2/SD|
The rationale for the fifty or one hundred miles from land dividing line is probably based on the desire to separate "casual overwater" operations (such as crossing rivers or small lakes) from over ocean crossings. In reality the choice should be based on the ability of the passengers and crew to self-rescue themselves (i. e. swim or wade to shore) and the time likely to pass between ditching and rescue.
Flights in the Bahamas and West Indies, for example, may never be more than 40 miles from land, yet rescue may take days or weeks. It does not seem reasonable to expose air carrier or private passengers to several days in the open sea hanging to a seat cushion albeit within 50 miles of the proverbial desert island. ICAO rules for water survival equipment call for life jackets beyond fifty miles and life rafts for all operations beyond 100, 200, or 400 miles from land, regardless of the presence or absence of passengers (11). The distance specified depends on the number of engines. ICAO does qualify the distance as being "from land suitable for making an emergency landing." ICAO also requires flotation gear when air carriers operate at airports where a mishap is likely to result in water contact.
It is also worth observing that many air carriers routinely operate beyond the 50 mile distance with no life rafts aboard. Waivers to the equipment rules are frequent for domestic US air carriers. (Some domestic routes, such as New York-Miami greatly exceed 50 miles from land.)
We recommend that the rules be changed and simplified. The air carrier and FAR 91D rules should be identical. The life raft specified for all "for hire" operations should be the same. We do feel that all passenger carrying flights should provide flotation gear for all occupants. Crew only flights should not be required to carry any equipment, similar to rules for parachutes. (This is based on a desire to minimize regulatory requirements, not that we feel crew members are expendable) In addition, the practice of granting waivers for air carriers should be discontinued. Table VII below summarizes our recommendations.
|Distance From Land|
|Passengers--Private||None||FG||LP / SD|
|Passengers--For Hire||None||FG / SD||LP / LR|
|Air Taxi||FG||FG / SD||LP/LR|
|Corporate||FG||LP / SD||LP / LR|
|Airline||FG||LP / SD||LP / LR|
There are two final points to make. We feel that while the 50 mile rule is too far, it is not likely to be changed. However, we would like to see the FAA adopt the ICAO stipulation that the "land" be suitable.
Recommended Survival Equipment
In spite of the recommendations that crew only operators under FAR 91 not be required to carry any survival equipment, I personally carry and recommend that all operators carry flotation devices for any cross-country flight. Pilots should remember that ditchings can occur anywhere, not just on overwater flights. We saw in Table IV that 68% of ditchings happen during non-overwater operations. It is ironic that after over 50 hours of overwater flying in 1984, I ditched crossing an eight mile wide river in 1985.
We recommend that all pilots carry flotation gear for all occupants on all crosscountry flights. Even a Coast Guard approved boat cushion is better than nothing (although not much better). Further, as we have seen, gear which is well stowed in the rear of the airplane is hardly better than no gear at all. Any water survival gear should be close at hand for seated occupants. Of course, life vests should be worn and life rafts carried during all open water flights.
All baggage should be well secured. We feel that the security of our baggage and equipment greatly eased escape from the airplane as it sank. While egress from crashes on land is usually less critical, adequate restraint of baggage will prevent the higher deceleration forces from producing loose missiles in the cockpit.
Passenger briefings on the fastening and unfastening of seat belts are required today. But pilots have a duty to ensure that the passengers really know how to get out of the airplane. This is particularly important where escape may require emergency exits that are not normally used. The passengers must be briefed on flotation gear and other emergency equipment on board the airplane. If pilots wear parachutes, it might be a good idea to unfasten the leg straps once you are below a safe bailout altitude. I understand that it used to be common for Navy pilots to do this prior to landing aboard the carrier.
Finally, pilots should remember that, with flotation gear, water landings may be easier on the body than land landings. A lake or a river might be an optimum site if a forced landing is imminent. Even the high-wing, fixed-gear airplane can be safely ditched. In fact, the type of airplane doesn't appear to be significant for non-transport airplanes.
Egress from U-206 Aircraft
The ditching checklist for the Cessna U-206F (5) includes a full-flap approach and landing. In the U-206, as opposed to the P-206, there is only one cabin door on the left side by the pilot seat. Additional access to and egress from the cabin is available through the cargo door located on the right side of the airplane. Because of mutual interference, the cargo door cannot be opened when the flaps are down. The flap circuit has an interlock to prevent flap motion when the cargo door is open.
If a flaps down landing is made, egress will be hindered by the inability to open the cargo door. There is a placard stating that one can open the cargo door enough to allow for escape. The procedure is somewhat complicated. I was not aware of the placard or the procedure prior to the accident. The airplane manual makes no mention of this possibility to open the rear cargo door while the flaps are down.
Because a U-206 may well require the cargo door for occupant egress, the implications of lowering the flaps on the ability to open the cargo door should be covered in the POH.
Videomaps of Shoreline
During the accident sequence, the airplane was in the clouds until shortly before ditching. During radar vectoring, it is not easy for pilots to remain aware of their position. During the power-off glide, the airplane was initially being steered toward the closest airport. When asked if the airplane was over water, the controller replied that it was. He then provided a radar steer toward the shore. Following the accident, we learned that the ATC radar at Patuxent River does not have a map of the shoreline available to the controllers. Thus, the ATC controller must rely on his personal knowledge of the area to determine the nearest land if the airplane happens to be over water.
We feel that in more critical circumstances, the availability of a videomap (or transparent overlay) showing the shoreline could allow an airplane to be steered toward shore more efficiently. This applies to all ATC radar installations near bodies of water, not only to Patuxent River NAS.
Communications with ATC
Pilots have all been reminded to advise ATC immediately when we have a problem. Nevertheless, it is often difficult for pilots to admit they need help. In this accident, while ATC was kept informed, I was still reluctant to state that the situation was critical. The first call to ATC when the engine failed described the problem as "an engine stoppage." On listening to the ATC tapes after the fact, it seems to be implied that I had intentionally secured one engine and would continue on the remaining engine(s). The term "stoppage" is a result of earlier engine icing test where the engine manufacturer insisted that induction ice did not cause an engine "failure."
Once the situation had become clear to ATC, the concern was if I would make land or not. Again, I was reluctant to say that the airplane would not make it to shore. Instead of saying so, I simply said "don't know if we can make it." when in fact I should have said "No way." In the 1970 DC-9 ditching, the pilots told the purser that "they might have to ditch" when, in fact, the ditching was inevitable (12). As pilots we must recognize this and try to avoid the "Chuck Yeager" syndrome of being too casual in our communications with ATC or passengers. We're not advocating crying wolf, but pilots tend to down play situations and others may not appreciate the severity of the situation.
N-1803Q had been used as the prototype for an ice protection system. During the flight tests, I had practiced egress through both doors in anticipation of possible bailout. In particular, the use of the cargo door had been practiced a number of times. It appears that this prior practice aided escape through the rear cargo door in spite of the difficulties encountered with the extreme nose down cabin attitude. This is a strong argument for egress practice.
In addition, all baggage and gear was well strapped down. This left the path to the rear door clear and prevented the baggage from creating a hazard during the impact. This definitely was a factor in the escape from the airplane. While flotation gear was carried, the airplane sank too quickly to retrieve it. Clearly, flotation gear must be stowed with regard to easy access to both crew and passengers.
The final lesson learned was that in an accident, things always go wrong. The door won't open; the airplane sinks faster than it should; etc. However, it does seem that with attention to other details, this doesn't matter. Emergency training, even on totally different equipment seems to have a way of carrying over.
The chief conclusion that can be drawn is that, with flotation gear aboard, ditching of light airplanes is a relatively safe procedure. Both personal experience and the accident statistics indicate that the survival rate is high even for the high-wing, fixed gear light airplane which heretofore has been thought to be especially risky to ditch.
The following recommendations are made:
Paul Alexander of the National Transportation Safety Board helped with obtaining the accident records of US civil ditchings. His help is greatly appreciated.
This paper was orginally published in 1988 (SAFE Journal, 18, pp. 6-15, Spring 1988). .
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