Stalls aren’t a ma­neu­ver, they’re an emer­gency


Flying - - CONTENTS - By John Zim­mer­man

Year af­ter year, the Na­tional Trans­porta­tion Safety Board and FAA nag pi­lots about ac­ci­dents caused by “loss of con­trol – in flight,” which usu­ally means a stall. The topic is well cov­ered in train­ing too. Dozens of ques­tions on the sub­ject ap­pear on the knowl­edge test, and stalls are per­formed on the prac­ti­cal test and are part of any de­cent flight re­view. And yet while ac­ci­dents caused by weather and con­trolled flight into ter­rain are de­clin­ing, stalls re­main one of the lead­ing causes of fa­tal ac­ci­dents in gen­eral avi­a­tion. Clearly, some­thing is not work­ing.

The AOPA Air Safety In­sti­tute tried to re­move the emo­tion from this sub­ject last year by div­ing more deeply into the data about stall ac­ci­dents. The re­sult is a well-re­searched study that reaches some sen­si­ble con­clu­sions. Most im­por­tant, it is a re­minder that there are no mir­a­cle cures for avi­a­tion safety.

The study should serve as a po­lite but firm re­but­tal to two com­mon ar­gu­ments in avi­a­tion: that safety prob­lems can be solved by adding new avion­ics or by go­ing back to “the way it used to be.” Tech­nol­ogy op­ti­mists, in­clud­ing the FAA, have sug­gested that an­gle-of-at­tack in­di­ca­tors are the so­lu­tion, and some reg­u­la­tions have been ad­justed to make them eas­ier to in­stall. On the other hand, the stick-and-rud­der crowd loudly pro­claims that a re­turn to spin train­ing (which hasn’t been re­quired for pri­vate pi­lots in more than 60 years) would help.

While nei­ther idea is nec­es­sar­ily bad, AOPA’s re­port doesn’t turn up much ev­i­dence that tech­nol­ogy or spin train­ing will re­duce stall ac­ci­dents. A pi­lot has to be look­ing at an AOA gauge for it to help, and in any case, few air­plane own­ers are shelling out the money to in­stall them. As far as spin or upset train­ing, most fa­tal stall ac­ci­dents hap­pen be­low 500 feet, where no amount of train­ing will lead to a suc­cess­ful out­come.

Part of the prob­lem is that “stall” doesn’t de­scribe the prob­lem very well. Many take­off stalls have more to do with per­for­mance plan­ning or weigh­tand-bal­ance mis­takes than poor stick-and-rud­der skills. If you’re tak­ing off over gross on a 95-de­gree day from a 2,000-foot strip, the en­su­ing stall is re­ally just the fi­nal blow, not some ran­dom fail­ure of air­man­ship. Like­wise, a sig­nif­i­cant pro­por­tion of stalls in home­built air­planes are caused ei­ther by de­sign is­sues (such as poor lat­eral sta­bil­ity) or ba­sic pro­fi­ciency is­sues (the pi­lot hasn’t flown in months or years as the air­plane was be­ing built). A spin train­ing ses­sion 10 years ago won’t help in ei­ther case.

Clearly, our cur­rent one-size-fits-all ap­proach to stall train­ing, one that is fo­cused on rigid pro­ce­dures and spe­cific per­for­mance stan­dards, is not do­ing a good job of pre­par­ing pi­lots for life out­side the prac­tice area. Far bet­ter to teach stalls the way many CFIs

are now teach­ing weather fly­ing — by build­ing it into re­al­is­tic sce­nar­ios. If a suc­cess­ful cross-coun­try flight be­gins with a proper weather brief­ing, then a safe (and stall-free) take­off be­gins with a good pre­flight plan. But how of­ten do flight in­struc­tors talk about stalls in the con­text of run­way per­for­mance?

Typ­i­cally dur­ing train­ing, stalls are a box to check since they are ma­neu­vers re­quired for check rides. At 3,500 feet, with the wings level and the air­speed de­creas­ing by 1 knot per sec­ond, a stall can seem like a nor­mal, pre­dictable event. The ac­ci­dent re­ports sug­gest this is ter­ri­bly mis­lead­ing. A sur­pris­ing num­ber of fa­tal stall ac­ci­dents hap­pen on take­off or go-around — not the dreaded base-to-fi­nal turn — and are of­ten ac­com­pa­nied by a sharp pull-up or a steep turn.

Re­al­is­tic stall train­ing should in­clude th­ese same ele­ments, in­clud­ing in­creas­ing an­gle of bank and per­haps even in­tro­duc­ing some dis­trac­tion. For de­par­ture stalls, the air­plane should be slowed as much as prac­ti­cal to sim­u­late a real take­off and then per­haps be pulled back swiftly as if to make it over a loom­ing ob­sta­cle. Au­topi­lot us­age is an­other key area to train on: Stalls can eas­ily hap­pen dur­ing climb with the au­topi­lot en­gaged, or af­ter lev­el­ing off from a de­scent with­out adding power. The sur­prise of hear­ing the au­topi­lot kick off at a high an­gle of at­tack is usu­ally the start of a bad sce­nario.

An­other bad train­ing habit that needs to die is the “pull it on back and get it good and stalled” ma­neu­ver. In­struc­tors who teach this might be do­ing more harm than good be­cause the key les­son for pi­lots to learn is not what a deep stall feels like — it’s how to im­me­di­ately re­act to signs of stall by un­load­ing the wing. A some­what anal­o­gous pro­ce­dure in he­li­copters in­volves low ro­tor ro­ta­tions per minute, which can lead to ro­tor-blade stall. In­stead of in­ves­ti­gat­ing the edges of the low ro­tor rpm en­ve­lope, he­li­copter pi­lots are taught to im­me­di­ately lower the col­lec­tive and in­crease en­gine power when they hear the warn­ing horn. It has to be­come an in­stinct.

The same idea works for fixed-wing pi­lots. If you hear the stall horn, you need to push as an au­to­matic re­ac­tion. Only then can you take time to con­sider what the un­der­ly­ing is­sue is. Right now, some pi­lots might hear the horn and think they need to “pull it on back” be­cause that’s what they do on a flight les­son.

More than any­thing, stall train­ing can’t be done in iso­la­tion. Pre­vent­ing loss of con­trol is so fun­da­men­tal that it in­volves all parts of safe fly­ing, re­quir­ing both the main­te­nance of good habits and the ap­pli­ca­tion of thought­ful safety mar­gins. Repet­i­tive ma­neu­vers are only a small part of the so­lu­tion. Air­craft mastery is the ultimate goal — be­ing able to fly a pre­cise air­speed at all times, us­ing the au­to­ma­tion if needed, and keep­ing the air­plane go­ing ex­actly where you want it.

Both the FARs and per­sonal min­i­mums dic­tate hard lim­its to prevent fuel is­sues (my own is to al­ways land with one hour of fuel in the tanks). The same can be done for stalls: Avoid low passes, avoid banks over 30 de­grees in the pat­tern, do an hon­est weight-and-bal­ance cal­cu­la­tion, build in mar­gins for take­off per­for­mance, and fly Vref +10 and -0 on fi­nal. If you fol­low those rea­son­able rules, an in­ad­ver­tent stall is exceedingly un­likely in most air­planes.

Stalls aren’t a ma­neu­ver at which to be­come pro­fi­cient; they are a mis­take to avoid, like fly­ing VFR into IMC or run­ning out of fuel (you’ll no­tice we don’t prac­tice that dur­ing pri­mary train­ing). Bet­ter to learn how to rec­og­nize im­pend­ing doom and avoid it than to be able to min­i­mize al­ti­tude loss or main­tain head­ing within 5 de­grees af­ter it hap­pens.


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